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The 7th Asian Silicon Symposium
Contents
Welcome 1
Committee 2
Program at a Glance 3
General Information 4
Abstract 8
Plenary Lecture 9
Keynote Lecture 13
Invited Lecture 21
Short Oral Presentation 46
Poster Presentation 57
The 7th Asian Silicon Symposium
WELCOME ǀ Page 1
Welcome On behalf of the organizing committee, it is our pleasure to welcome you to the 7th ASIAN
SILICON SYMPOSIUM (ASiS-7), which is held in Nanyang Technological University,
Singapore from 28th July to 31st July 2019.
The Asian Silicon Symposium (ASiS) takes place in Asia biennially and has been hosted in
turn by the silicon research communities of Japan, Korea, and China. Previous ASiS meetings
were successfully held at Miyagi (Japan) in 2007, Jeju (Korea) in 2008, Hangzhou (China) in
2010, Tsukuba (Japan) in 2012, Jeju (Korea) in 2015, Jinan (China) in 2017. This is the first
ASiS meeting to be hosted in Singapore.
Following the success of previous ASiS meetings, ASiS-7 aims at providing an engaging
platform to bring together leading researchers, scientists and students in the field of silicon
chemistry to present their perspective in research, exchange their scientific findings, cultivate
mutual understanding, and foster possible collaborations. ASiS-7 is not only open to the Asian
silicon community, but also the world’s silicon community.
The major themes of ASiS-7 cover synthesis, structure, catalysis and materials. There will be
four plenary lectures, eight keynote lectures, twenty five invited lectures, ten oral presentation
and thirty one poster presentation from various research units participating in the event.
We are looking forward to giving you a warm welcome to you at the ASiS-7. We hope that
you will find the symposium both enjoyable and valuable, whereby you can discuss, interact
and collaborate with silicon chemists from different areas to make a great development in
silicon chemistry.
Cheuk-Wai So
Chairman, ASiS-7
Associate Professor
Division of Chemistry and Biological Chemistry
School of Physical and Mathematical Sciences
Nanyang Technological University
Nanyang Technological University
WELCOME ǀ Page 2
Committee ASiS International Advisory Board
Stephen Clarke University of South Australia, Australia
Geun-Mook Choi KCC Corporation, Korea
Shengyu Feng Shangdong University, China
Jianxiong Jiang Hangzhou Normal University, China
Mitsuhiro Takarada Shin-Etsu Chemical Co., Ltd, Tokyo, Japan
Soichiro Kyushin Gunma University, Japan
Ching-Wen Chiu National Taiwan University, Taiwan
Akira Sekiguchi University of Tsukuba, Japan
Hiromi Tobita Tohoku University, Japan
Norihiro Tokitoh Kyoto University, Japan
Caihong Xu Chinese Academy of Science, China
Bok Ryul Yoo Korea Institute of Science and Technology, Korea
Honorary ASiS International Advisory Board
Mitsuo Kira Tohoku University, Japan
Myong Euy Lee Yonsei University, Korea
Local Organizing Committee
Chairman
Cheuk-Wai So
Member
Rei Kinjo, Felipe Garcia
Secretaries
Chia Cher Chiek, Leong Bi-Xiang, Fan Jun, Meldon Wee Yi Shuo, Ong Xin Yi Melissa, Lee
Jiawen
Nanyang Technological University
GENERAL INFORMATION ǀ Page 4
General Information Location
The 7th Asian Silicon Symposium is held at the School of Physical and Mathematical Sciences
(SPMS), Nanyang Technological University (NTU), Singapore.
(https://spms.ntu.edu.sg/ContactUs/Pages/Plan-Your-Visit.aspx). Plenary, keynote and invited
lectures, as well as short oral presentations are held at SPMS-LT1, SPMS-LT2 and SPMS-LT3.
Poster presentation is held at the MAS Atrium.
Access to the School of Physical and Mathematical Sciences, NTU
By Symposium Shuttle Bus
There is a complementary shuttle bus from the Hotel Jen, Tanglin at 8:00 am to the symposium
venue
The 7th Asian Silicon Symposium
GENERAL INFORMATION ǀ Page 5
By Taxi (Travel time: city centre → NTU: 30 mins; Fare: around $30)
All taxis in Singapore use a fare meter and fares are fixed so bargaining is not required.
Payment is usually by cash although a few taxis do accept credit cards. You may enquire about
surcharges when in doubt and request a receipt. https://www.cdgtaxi.com.sg/
By MRT (subway) and Bus (Travel time: city centre → NTU: > 1.5h)
To access public transport in Singapore, it is highly recommended to purchase the Singapore
Tourist Pass (S$ 10) for unlimited rides. The Pass can be purchased at the Airport (Changi
Airport) https://www.ezlink.com.sg/home-tourist.
Take the MRT East-West (Green) line and alight at Pioneer (EW 28) MRT Station (Exit A).
Thereafter, take Singapore Bus Service (SBS) bus service no. 179 at the bus stop located just
next to the MRT station. Alight from the bus at the bus stop B11 WEE KIM WEE Sch of
Comm & Info (27231). Then, walk 10 minutes to the School of Physical and Mathematical
Sciences.
Nanyang Technological University
GENERAL INFORMATION ǀ Page 6
Secretariat
The secretarial office is located at the MAS Atrium on the 3rd floor of the School of Physical
and Mathematical Sciences.
Registration
The registration is conducted in the Welcome Reception on 28th July at 6:00 pm in the Hotel
Jen, Tanglin. It can also be achieved at the Registration Booth in the MAS Atrium on the 3rd
floor of the School of Physical and Mathematical Sciences.
Lecture and Oral Presentation
The official language of ASiS-7 is English. The time allocation for presentation is as follows:
Plenary Lecture : 40 mins + 10-min Q&A
Keynote Lecture : 30 mins + 10-min Q&A
Invited Lecture : 25 mins + 5-min Q&A
Oral Presentation : 15 mins + 5 min Q&A
Presentation should be executed using an appropriate software tool such as Keynote or
PowerPoint. Speakers can use either their own laptops or a desktop provided in each lecture
theatre for presentation. It is necessary to bring a suitable port adapter for Macintosh laptops
and Microsoft Surface. Presentation slides should be set-up at the latest during the break
preceding the presentation and they should be ready before the start of the session.
Poster Presentation
The size of a poster is 594 x 841 mm (Width x Height). Poster presentation is held on 30th July
at 6:00 pm in the MAS Atrium. Posters should be mounted on the poster boards in the MAS
Atrium on 29th July 2019 in accordance with the poster abstract number.
Outstanding poster presentation will be awarded by the Best Poster Award.
Meal
Lunch and coffee break are available in the MAS Atrium on the 3rd floor of the School of
Physical and Mathematical Sciences. Dinner is provided during the poster presentation session.
The 7th Asian Silicon Symposium
GENERAL INFORMATION ǀ Page 7
Social Events
➢ Welcome Reception
Date: 28th July 2019, 6:00 – 8:00 pm
Location: Hotel Jen, Tanglin
➢ Excursion
Date: 31st July 2019, 3:00 – 6:00 pm
Location: Flower Dome and Cloud Forest at The Gardens by the Bay
(https://www.gardensbythebay.com.sg/en.html).
Tour bus is provided in front of the School of Physical and Mathematical Sciences
➢ Banquet
Date: 31st July 2019, 7:00 pm – 9:00 pm
Location: Hotel Jen, Tanglin
➢ Accompanying Person Program
Date: 30th July 2019
Location: NTU registration booth (9:00 am)
Tour: China Town → Merlion → Masjid Sultan → Kampong Glam → Lunch at NTU →
Cooking Class at Tanjong Hall in NTU → Dinner at NTU
Date: 31st July 2019
Location: NTU registration booth (9:00 am)
Tour: Singapore Discovery Centre → Lunch at NTU → Gardens by the Bay
Nanyang Technological University
PLENARY LECTURE ǀ Page 8
Abstract
Plenary Lecture
Keynote Lecture
Invited Lecture
Short Oral Presentation
The 7th Asian Silicon Symposium
PLENARY LECTURE ǀ Page 9
Recent progress in silicon chemistry and its valence isoelectronic
neighbors
Herbert W. Roesky
Institute of Inorganic Chemistry, University of Göttingen, Germany
This year the chemical community celebrates the 150th year of the periodic system and therefore it a
chance for the chemists to report new results on silicon and aluminum, the ubiquitous elements in the
earth`s crust. BF an isoelectronic molecule to SiO was prepared from BF3 and boron at 2000 °C and 1
mm pressure by P. L. Timms in 1967.
BF is only stable at high temperatures and condenses at liquid nitrogen temperature (-196 °C) to a
green polymer, which has not been characterized.
BF3 + 2 B → 3 BF
BF is an interesting molecule because it is isoelectronic to CO and N2. The latter compounds are
forming well known metal complexes.
We stabilized BF during the reduction with cAAC (cyclic alkylamino carbene) according to the
following reaction
This adduct was characterized by single crystal X-ray structural analysis and is stable at room
temperature for several months. The CV of the BF adduct exhibits one electron reversible oxidation.
The formation, isolation and characterization of the cation will be discussed. It is well known that B-Si
compounds have found a brought application in organic chemistry. The corresponding preparation of
Al-Si compounds is so far hardly reported. We used successfully interconnected bissilylen RSi(:)Si(:)R
( R= adamantyl) and AlH3·NR3 for the preparation of Al-Si molecules.
In recent years we were able to stabilize small silicon compounds with cAAC (cyclic alkylamino
carbene) such as SiH2 and various R2SiCl and RSiCl2 radicals.
Moreover, we successfully isolated silanylidene and germanylidene anions, valence isoelectronic
species to phosphinidene. The cAACPLi·(thf)2 dimer reacts with fluorinated carbon compounds as well
as with SiCl4 and GeCl4 under elimination of LiF and LiCl, respectively, to the corresponding
phosphinidene derivatives.
PL – 01
Nanyang Technological University
PLENARY LECTURE ǀ Page 10
Nanostructuring of Bridged Silsesquioxanes and applications
Michel Wong Chi Man,a*
aInstitut Charles Gerhardt Montpellier, ENSCM, 8 rue de l’école normale, 34296 Montpellier (France)
Bridged Silsesquioxanes (BS)1 represent a family of hybrid silica which has emerged as an important
class of materials in the early 1990s. Since then a large number of such hybrid materials have been used
in several fields of applications. A decade later PMO (Periodic Mesoporous Organosilicas) have been
produced from simple precursors via the surfactant-mediated structuring and, nearly at the same time,
nano-structured BS were obtained by a self-structuring process (Figure 1).
Figure 1. Structuring of Bridged Silsesquioxanes
BS are obtained by hydrolysis-condensation of poly(trialkoxy)organosilanes, (RO)3Si-X-Si(OR)3
(X=organic bridging unit). The organic units are regularly retained throughout the hybrid network
thanks to the strong covalent Si-C bonds. The combination of the organic fragments and of the silica
network allows the structuring as well as the fine-tuning of targeted properties of these materials. My
talk will be focused on the following:
- Synthesis and self-structuring of BS,2,3
- Synthesis of Nano-PMO,4
- Applications in catalysis,5
- Application of mechanized nano-PMO in nanomedicine field.6-8
References
1. Corriu R. J. P., Moreau J. J. E., Thépot P. Wong Chi Man M. Chem. Mater. 1992, 114, 1217-1224.
2. Moreau J. J. E., Vellutini L., Bied C., Wong Chi Man M., J. Am. Chem. Soc. 2001, 123, 6700-6710.
3. Arrachart G., Creff G., Wadepohl H., Blanc C., Bonhomme C., Babonneau F., Alonso B., Bantignies J-L., Carcel C.,
Moreau J. J. E., Dieudonné P, Sauvajol J-L, Massiot D., Wong Chi Man M. Chem. Eur. J. 2009, 15, 5002-5005.
4. Croissant J., Cattoën X., Wong Chi Man M., Dieudonné P., Charnay C., Raehm L., Durand J-O. Adv.Mater., 2015, 27,
145 -149.
5. Monge-Marcet A., Pleixats R., Cattoën X., Wong Chi Man M. J. Mol. Catal. A, Chemical 2012, 357, 59-66.
6. Théron C., Gallud A., Carcel C., Gary-Bobo M., Maynadier M., Garcia M., Lu J., Tamanoi F., Zink J. I., Wong Chi Man
M. Chem. Eur. J., 2014, 20 (30), 9372-9380.
7. Croissant J., Maynadier M., Mongin O., Hugues V., Blanchard-Desce M., Chaix A., Cattoën X., Wong Chi Man M.,
Gallud A., Gary-Bobo M., Garcia M., Raehm L., Durand J-O. Small, 2015, 11, 295-299.
8. Noureddine A., Gary-Bobo M., Lichon L., Garcia M., Zink J. I., Wong Chi Man M., Cattoën X., Chem. Eur. J., 2016, 22,
9624-9630.
PL – 02
The 7th Asian Silicon Symposium
PLENARY LECTURE ǀ Page 11
A Systematic Study on Metallabenzenyl Anions
Substituted by a Heavier Group 14 Element
Norihiro Tokitoh,a,b,* Shiori Fujimori,a Shingo Tsuji,a Yoshiyuki Mizuhataa,b
aInstitute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan b Integrated Research Consortium on Chemical Sciences, Uji, Kyoto 611-0011, Japan
We have recently reported the synthesis and isolation of 2-tert-butylgermabenzenylpotassium (K+.2-),
the first example of heavy phenyl anion, i.e., a Ge analogue of phenylpotassium, by the reaction of 1-
Tbt-2-tert-butylgermabenzene 1 with KC8.1 Spectroscopic and X-ray crystallographic analysis together
with theoretical calculations revealed that K+.2- exhibits not only aromatic character due to the C5Ge
-system but also germylene character due to the delocalization of negative charge on the five ring
carbon atoms.1-3 Stannabenzenylpotassium (K+.4-), the Sn analogue of K+.2-, was also synthesized and
isolated by the treatment of an equilibrated mixture of the corresponding stannabenzene 34 and its dimer
with KC8.5
Next, we attempted the synthesis of the corresponding silabenzenyl anion. However, the treatment of
1-Tbt-2-t-Bu-silabenzene 4 with KC8 or LiNpah resulted in the formation of dianion 52- as yellow
crystals as shown in Scheme 1.6 The formation of dianions (2K+.52- and 2Li+.52-) was evidenced by
their X-ray crystallographic analysis and the trapping with D2O giving the deuterated product 6.
The structures, properties, and formation mechanisms of metallabenzenyl anions (K+.2- and K+.4)
and dianions (2K+.52- and 2Li+.52-) will be discussed in detail.
References
1. Mizuhata, Y.; Fujimori, S.; Sasamori, T.; Tokitoh, N. Angew. Chem. Int. Ed. 2017, 56, 4588-4592.
2. Fujimori, S.; Mizuhata, Y.; Tokitoh, N. Chem. Commun. 2018, 54, 8044-8047.
3. Fujimori, S.; Mizuhata, Y.; Tokitoh, N. Chem. Lett. 2018, 37, 708–710.
4. Mizuhata, Y.; Fujimori, S.; Noda, N.; Kanesato, S.; Tokitoh, N. Dalton Trans. 2018, 47, 14436-14444.
5. Fujimori, S.; Mizuhata, Y.; Tokitoh, N. Chem. Eur. J. 2018, 24, 17039-170
6. Tsuji, S.: Mizuhata, Y.; Tokitoh, N. 99th CSJ Annual Meeting, 3PC-20, Kobe, 2019, March 18.
PL – 03
Nanyang Technological University
PLENARY LECTURE ǀ Page 12
Challenge: Mimicking transition metals using Si
Tsuyoshi KATO
a Université de Toulouse, UPS, LHFA, 118 route de Narbonne, F-31062 Toulouse, France, and CNRS, LHFA
UMR 5069, F-31062 Toulouse, France.
Silylenes are neutral silicon species featuring a divalent silicon atom with only six valence electrons
and they are in general highly reactive transient species with a short life time. Since the discovery of
first stable silylenes, several methods to stabilize such species have been developed. Among them, the
use of a donating ligand, which thermodynamically stabilizes silylenes by elecron donation but also
increases the steric protections, have been recognized to be an efficient methodology to synthesize
various types of silylenes.
Since several years, we are developing the chemistry of silylenes complexed with a phosphine ligand
I. Of particular interest, they retains the silylene reactivity in spite of their high stability and presents
somewhat transition metal like behavior.1 Here we will show their chemistry and some interesting
perspectives.
References
1. a) R. Rodriguez, D. Gau, T. Kato, N. Saffon-Merceron, A. De Cózar, F. P. Cossío, A. Baceiredo, Angew. Chem. Int. Ed.
2011, 50, 10414; b) R. Rodriguez, Y. Contie, D. Gau, N. Saffon-Merceron, K. Miqueu, J.-M. Sotiropoulos, A. Baceiredo,
T. Kato, Angew. Chem. Int. Ed. 2013, 52, 8437; c) R. Rodriguez, Y. Contie, Y. Mao, N. Saffon-Merceron, A. Baceiredo,
V. Branchadell, T. Kato, Angew. Chem. Int. Ed. 2015, 54, 15276; d) R. Rodriguez, Y. Contie, R. Nougué, A. Baceiredo,
N. Saffon-Merceron, J.-M. Sotiropoulos, T. Kato, Angew. Chem. Int. Ed. 2016, 55, 14355.
PL – 04
The 7th Asian Silicon Symposium
KEYNOTE LECTURE ǀ Page 13
Heavier Unsaturated Group 14 Species: Beyond the Carbon Copy
David Scheschkewitz*
Chair in General and Inorganic Chemistry, Saarland University, 66123 Saarbrücken, GERMANY
Heavier double bonds attracted enormous interest since more than a century. Early attempts to
synthesize stable species with such double bonds exclusively resulted in oligo-or polymeric materials
despite occasional claims to the contrary. As a consequence, the classical "double bond rule" surmised
that double bonds between two elements beyond the 2nd row of the periodic table would be unstable.
The search for exceptions to this rule and thus for parallels to carbon chemistry was on and finally
successful with the isolation of stable compounds with formal Ge=Ge, Sn=Sn, Si=Si, and P=P units in
the late 1970s and early 1980s. The first 20 years of research in this area focussed on the structural
peculiarities and the reactivity of the heavier alkene analogues and to this day enormous efforts are
devoted to mimic the hallmarks of C=C bonds in organic chemistry such as conjugation and functional
group tolerance.1
As a deeper understanding of the theoretical foundations of the peculiar bonding in heavier main
group elements develops, an additional focus has been directed to the differences rather than the
similarities between the first two rows and the rest of the periodic table. In unsaturated systems in
particular, a strong preference for cluster-like arrangements has become obvious, increasingly so as the
number of cluster vertices and the degree of unsaturation rises.2 The unique structure and electronic
properties of unsaturated clusters of the heavier main group elements reflect those of the corresponding
nanomaterials and bulk surfaces, which potentially opens a wide field of application, e.g. in
photovoltaics, microprocessors or data storage.
References
1. For examples of reviews see: (a) Fischer, R. C.; Power, P. P Chem. Rev. 2010, 110, 3877. (b) Präsang, C.; Scheschkewitz,
D. Chem. Soc. Rev. 2016, 45, 900.
2. Recent review: Heider, Y., Scheschkewitz, D. Dalton Trans. 2018, 47, 7104.
KL – 01
Nanyang Technological University
KEYNOTE LECTURE ǀ Page 14
Siloles as Precursors for Unusual Silicon Compounds
Zhaowen Dong, Crispin Reinhold, Thomas Müller*
Institute of Chemistry, Carl von Ossietzky University Oldenburg
Carl von Ossietzky-Str. 9-11, D-26129 Oldenburg, Federal Republic of Germany, European Union
Siloles are of great interest, in particular in materials chemistry, due to their favorable photophysical
properties.1 We started our experimental work on siloles with an attempt to stabilize silyl radicals 1 and
we found during this endeavour an easy synthetic access to silole dianions 2.2 These silole dianions 2
have been the starting point for the synthesis of an intriguing set of unusual silicon compounds including
silacalicenes 3, isomers of disilabenzene 4 and unusual silylenes 5 that are stabilizes by
homoconjugation with a remote C=C double bond.3,4 In this presentation, we will summarize parts of
our exciting journey through silole chemistry and point out future directions.
Figure 1. Unusual silicon compounds derived from siloles.
References
1. Yamaguchi, S.; Tamao, K. J. Chem. Soc., Dalton Trans. 1998, 3693 - 3704.
2. Dong, Z.; Reinhold, C. R. W.; Schmidtmann, M.; Müller, T. Organometallics 2018, 37, 4736 - 4734.
3. Reinhold, C. R. W.; Dong, Z.; Winkler, J. M.; Steinert, H.; Schmidtmann, M.; Müller, T. Chem. Eur. J. 2018, 24, 848-
854.
4. Dong, Z.; Reinhold, C. R. W.; Schmidtmann, M.; Müller, T. J. Am. Chem. Soc. 2017, 139, 7117-7123.
KL – 02
The 7th Asian Silicon Symposium
KEYNOTE LECTURE ǀ Page 15
A New Form of Silicon: Metal-Atom Encapsulating Silicon Cage
Compounds
Atsushi Nakajima
Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi,
Kohoku-ku, Yokohama 223-8522, Japan
Since well-established function miniaturization of silicon (Si) devices with photolithography has
almost reached its technological limit, it is urgent to explore new Si based low-dimensional functional
nanomaterials (e.g. Si nanodots, nanowires, nanosheets) with bottom-up technologies utilizing
physicochemical synthetic methods in the gas and liquid phases. Furthermore, silicene, a counter part
of graphene, is a two-dimensional (2D) Si nanomaterial, exhibiting high in-plane electric conductivity.
Since the Si atom, unlike the C atom, generally prefers to sp3 hybridization, sp2-like Si-Si bonds should
be formed to make the 2D flat silicene. However, the 2D silicene on a metal surface is non-flat due to
the structural deviation from the sp2 conformation. Alternatively, one can assume that a rounded silicene
will have a caged surface consisting of sp2-Si by analogy with C60 fullerene. Although a lot of
experimental and theoretical researches have been conducted, a “zero dimensional (0D)” caged Si
compound, including Si60, has not been identified.
A suggestive clue for the 0D Si cage was shown to be metal-encapsulation inside a Si cage, M@Sin,
by mass spectrometry for mixed vapors of metal and Si in 1987.1 Although some other experimental
and theoretical researches have been reported, the caged Si compounds have never been realized as a
new Si form. On the other hand, a physical concept of “superatoms” has been introduced, where new
atomic-like orbitals (super atomic orbital; SAO) are constructed by valence electrons delocalized over
nanoclusters comprised of several to hundreds of atoms.
We have found a periodic family of M@Si16 superatoms based on mass spectrometry, where halogen-
like (Sc@Si16–), rare gas-like (Ti@Si16
(0)), and alkali-like (V@Si16+, Ta@Si16
+) SAs have been
demonstrated by the group-3, -4, and -5 atom encapsulations, respectively. They complete their SAO
closure for the same number of valence electrons (68e), where 64 and 4 electrons come from the 16 Si
atoms and the central M atom including charged states. Beyond the surface
immobilization of the M@Si16 superatoms,2,3,4 we have developed a large-
scale synthesis method for M@Si16 (M = Ti and Ta) by scaling up the clean
dry-process with a highpower impulse magnetron sputtering (nanojima®)
and by a direct liquid embedded trapping (DiLET) method5. The
spectroscopic results reveal that the structures of isolated M@Si16
superatoms are the metalencapsulating tetrahedral Si-cage (METS)
consisting of sp2-Si atoms.6
References:
1. S.M. Beck, J. Chem. Phys. 1989, 90, 6306.
2. M. Nakaya, T. Iwasa, H. Tsunoyama, T. Eguchi, A. Nakajima, Nanoscale 2014, 6, 14702.
3. M. Shibuta, T. Ohta, M. Nakaya, H. Tsunoyama, T. Eguchi, A. Nakajima, J. Am. Chem. Soc. 2015, 137, 14015.
4. M. Shibuta, T. Kamoshida, T. Ohta, H. Tsunoyama, A. Nakajima, Comm. Chem. 2018, 1, 50.
5. H. Tsunoyama, H. Akatsuka, M. Shibuta, T. Iwasa, Y. Mizuhata, N. Tokitoh, A. Nakajima, J. Phys. Chem. C 2017, 121,
20507.
6. H. Tsunoyama, M. Shibuta, M. Nakaya, T. Eguchi, A. Nakajima, Acc. Chem. Res. 2018, 51, 1735.
KL – 03
Nanyang Technological University
KEYNOTE LECTURE ǀ Page 16
Preparation of Functional Silicone Materials via Thiol-ene Click
Reaction
Shengyu Feng
Key Laboratory of Special Functional Aggregated Materials & Key Laboratory of Colloid and Interface
Chemistry (Shandong University), Ministry of Education; School of Chemistry and Chemical Engineering,
Shandong University, Jinan 250100, P. R. China
Silicone materials possess many unique properties such as non-toxicity, physiological inertness,
flame retardancy, high- and low- temperature resistance, weather resistance, and electrical insulation,
and functional silicone materials have more special applications. 1, 2 Among them, silicone materials
have great potential in wastewater treatment. The thiol-ene reaction is one of the click reactions.3 The
application of thiol-ene click reaction to the synthesis of sewage treatment functional silicone materials
is of great significance for increasing the productivity.
The lecture intends to introduce a few functionalized silicone materials including functional
polysiloxanes, silicone gels, and silicone sponges prepared by the thiol-ene click reaction (Scheme 1).
The polyether modified polysiloxanes were used to detect Hg2+ and Fe3+ in water, and detection limits
were wide. The silicone gels and silicone sponges were used for fast oil water separation, and they both
had high separation efficiency. The super-amphiphilic silicone sponge was used for the efficient
adsorption and filtration of dye and metal ion, and the filtrate can reach drinkable levels. 4, 5 This lecture
will also enlarge the applications of silicone materials.
Scheme 1. Preparation of functional silicone materials via thiol-ene click reaction
References
1. Feng S, Zhang J, Li M, and Zhu Q. Organosilicon Polymers and Application. Beijing: Chemical Industry Press, 2010; pp
1-20.
2. Yilgör E and Yilgör I. Prog. Polym. Sci. 2014, 39, 1165-1195.
3. Lowe AB. Polym. Chem. 2014, 5, 4820-4870.
4. Cao J, Wang D, An P, Zhang J, and Feng S. J. Mater. Chem. A 2018, 6, 18025-18030.
5. Zuo Y, Cao J and Feng S. Adv. Funct. Mater. 2015, 25, 2754-2762.
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The 7th Asian Silicon Symposium
KEYNOTE LECTURE ǀ Page 17
Low-Valent Silicon Chemistry from an Industrial Perspective
Elke Fritz-Langhalsa, Richard Weidnera,*
aWacker Chemie AG, Consortium für Elektrochemische Industrie,
Zielstattstraße 20, D-81379 Munich, Germany
Silyliumylidene cations RSi:+ are of increasing interest in chemistry. Two vacant orbitals and a lone
pair of electrons combine the characters of both strongly electrophilic silylium cations R3Si+ and
nucleophilic silylenes R2Si:. 1 Whereas the reactivity of silylenes R2Si: and silylium cations has been
investigated in detail within the past 20 years, the reactivity of silyliumylidene cations RSi:+, however,
is still in its infancy. Jutzi’s Cp*Si:+ B(C6F5)4- (1, Cp* = pentamethylcyclopentadienyl),2 however, repre-
sents a unique cationic silyliumylidene structure, because the cationic silicon center is only stabilized
on one side by a Cp* residue and therefore has free coordination sites. The catalytic potential of this
extraordinary structure, however, was unknown.
We found that Cp*Si:+ efficiently catalyzes reactions which are of technical relevance in industrial
organosilicon chemistry. For example, it is a very efficient nonmetallic catalyst for the hydro-silylation
of alkenes3 (eq. 1) at low catalyst amounts of < 0.01 mole %, and for the Piers-Rubinsztajn reaction (eq.
2) which is a versatile tool to make controlled silicone architectures.
References
1. (a) Ahmad, S.U.; Szilvasi, T.; Inoue, S. Chem. Commun. 2014, 50, 12619. (b) Lee, V.Y; Sekiguchi, A. Organometallic
Compounds of Low-Coordinate Si, Ge, Sn and Pb; Wiley: Chichester, 2010. 2Jutzi, P.; Mix, A.; Rummel, B.; Schoeller,
W.W.; Neumann, B., Stammler, H.-G. Science 2004, 305, 849. 3Fritz-Langhals, E.; Jutzi, P.; Weidner, R. WACKER
Chemie AG, Precious metal-free hydrosilylation of unsaturated compounds catalyzed by cationic Si(II) complexes,
WO2017/174290 (12.10.2017).
KL – 05
Nanyang Technological University
KEYNOTE LECTURE ǀ Page 18
Synthesis and Reactivity of Acyclic Silylenes
Shigeyoshi Inoue
Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research Center, Technische
Universität München, Lichtenbergstraße 4, 85748 Garching bei München, Germany
Silylenes have recently shown fascinating reactivity patterns, which are normally observed almost
exclusively for transition metal complexes. In particular, very reactive representatives are considered
as promising candidates, which may become powerful and economical alternatives for catalytic
applications in the future. Acyclic silylenes are considered as very reactive species, due to their
proposed small HOMO-LUMO gaps. Recently, we found that imidazoline-2-iminato ligand supported
acyclic silylenes show unique reactivity and are capable to activate - and π- bonds of small molecules
under very mild reaction conditions.1-5 In this presentation, synthesis of selected acyclic silylenes and
their unique reactivity towards various small molecules will be described.
References
1. Ochiai, T.; Franz, D.; Inoue, S. Chem. Soc. Rev. 2016, 45, 6327.
2. Inoue, S.; Leszszyńska, K. Angew. Chem., Int. Ed. 2012, 51, 6167.
3. Wendel, D.; Reiter, D.; Porzelt, A.; Altmann, P.J.; Inoue, S.; Rieger, B. J. Am. Chem. Soc. 2017, 139, 17193.
4. Wendel, D.; Porzelt, A.; Herz. F. A.; Sarkar, D.; Jandl, C.; Inoue, S.; Rieger, B. J. Am. Chem. Soc. 2017, 139, 8134.
5. Reiter, D.; Holzner, R.; Porzelt, A.; Altmann, P.J.; Frisch, P.; Inoue, S. submitted.
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Synthesis and Reactions of a Cyclic Dialkylsilylene Containing a
Robust Carbon-Based Substituent
Ryo Kobayashi,a Shintaro Ishida,a Takeaki Iwamotoa
a Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
Silylenes have received much attention as important and reactive low-coordinate species in silicon
chemistry. Since the pioneering works on stable silylenes,1 various cyclic and acyclic silylenes that are
stabilized kinetically and electronically have been synthesized as isolable species and their structures
and reactivity have been extensively investigated. Previously, we have synthesized stable cyclic
dialkylsilylenes 1 that have a five-membered ring with four trialkylsilyl groups at 2,5-positions.2 These
silylene exhibit spectroscopic properties and reactivity that resemble those of transient dialkylsilylenes
with an intrinsic nature of silylene. Nevertheless, these cyclic dialkylsilylenes are not thermally very
stable; 1a and 1b undergo facile 1,2-silyl migration providing the corresponding cyclic silenes, while
1c provides unidentified insoluble materials upon heating. Very recently, we designed a more robust
substituent that contains bulky carbon-based protecting groups with a diminished migratory propensity
relative to that of the trialkylsilyl group. In this presentation, we would like to talk about synthesis and
reactions of new two-coordinate cyclic dialkylsilylene 2.3
Figure 1. Stable Two-coordinate Cyclic Dialkylsilylenes.
References
1. Jutzi, P.; Kanne, D.; Krüger, C. Angew. Chem. Int. Ed. Engl. 1986, 25, 164; Karsch, H. H.; Keller, U.; Gamper, S.; Müller,
G. Angew. Chem. Int. Ed. 1990, 29, 295; Denk, M.; Lennon, R.; Hayashi, R.; West, R.; Belyakov, A. V.; Verne, H. P.;
Haaland, A.; Wagner, M.; Metzler, N. J. Am. Chem. Soc. 1994, 116, 2691.
2. Kira, M.; Ishida, S.; Iwamoto, T.; Kabuto, C. J. Am. Chem. Soc. 1999, 121, 9722; Abe, T.; Tanaka, R.; Ishida, S.; Kira,
M.; Iwamoto, T. J. Am. Chem. Soc. 2012, 134, 20029; Ishida, S.; Abe, T.; Hirakawa, F.; Kosai, T.; Sato, K.; Kira, M.;
Iwamoto, T. Chem. Eur. J. 2015, 21, 15100.
3. Kobayashi, R.; Ishida, S.; Iwamoto, T. Angew. Chem. Int. Ed., (DOI: 10.1002/anie.201905198).
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KEYNOTE LECTURE ǀ Page 20
IRON, COBALT AND NICKEL COMPLEXES WITH SILYLENE
LIGANDS
Chunming Cui,* Yunping Bai
State Key Laboratory of Elemento-Organic Chemistry and College of Chemistry, Nankai University, Tianjin
300071, China
Silylenes, the carbene analogues of silicon, have emerged as a class of powerful ligands in
coordination chemistry and catalysis since the first N-heterocyclic silylene was reported in 1994 by
West. Recent advances in this field have shown that silylenes with different coordination numbers could
be available, and thus provided more chemical space for the tuning their electronic properties. However,
the employments of silylenes in organic catalysis remained largely unexplored. In this presentation, we
report the synthesis of iron and cobalt complexes with multiple dentate silylene ligands and their unique
chemical transformations.
We found these silylene-supported transition metal compounds enabled catalytic transformations of
C-H functionalization, alkyne trimerization and dinitrogen fixation. The mechanism and structural
analysis disclosed the silylenes both act as excellent σ-donors and π-acceptors in different coordination
spheres. These preliminary results demonstrated that the potentials of silylene ligands in coordination
chemistry and homogeneous catalysis can be widely explored.
Figure 1. Representative Silylene Complexes.
Acknowledgment.
We thank the National Natural Science Foundation of China for the support of this work.
References
1. Raoufmoghaddam, S.; Zhou, Y.; Wang, Y.; Driess. M. J. Organomet. Chem. 2017, 829, 2.
2. Ren, H.; Zhou, Y.; Bai, Y.; Cui, C.; Driess, M. Chem. Eur. J. 2017, 23, 5663.
3. Bai, Y.; Zhang, J.; Cui, C. Chem. Commun. 2018, 54, 8124.
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Molecular Silicon Clusters with Six and Seven Unsubstituted
Vertices via a Two‐step Reaction from Elemental Silicon
Thomas Fässler
Prof. Dr. Thomas Fässler, Technische Universität München, Department of Chemistry & WACKER Institute of
Silicon Chemistry, 85748 Garching, Germany,
Unsaturated silicon clusters with partial substitution and thus “naked” Si atoms are well studied
species as they are proposed intermediates in gas‐phase deposition processes. Although a remarkable
number of stable molecular clusters have been reported, they are typically obtained by multistep
syntheses. Herein we report on the application of a newly developed synthetic approach and the
formations of protonated [H2Si9]2−, and functionalized siliconoids [{Si(TMS)3}3Si9]−,
[{Si(TMS)3}2Si9]2− , [{Si(tBu)2H}3Si9]−, [{Si(iPr)3}2Si9]2−, [{Sn(Cy)3}2Si9]2−, and [{Sn(Cy)3}3Si9]−
through a one‐step synthesis from the binary alloy K12Si17 which is obtained by simply fusing the
elements K and Si.
The protonated [H2Si9]2− reveal a rather unexpected 1H‐NMR shift at ‐0.7 ppm and coupling with all
nine Si atoms indicating dynamic processes.1,2 The molecular functionalized anions display a
remarkable 29Si‐NMR shift range for example of +18 to ‐359 ppm for [{Si(tBu)2H}3Si9]−. The anions
are further characterized by ESI mass spectrometry and 13C as well as 119Sn NMR spectroscopy. Various
clusters are isolated as their (K‐222crypt)+ salts and structurally characterized by single crystal X‐ray
structure determination.3 For the first time also Raman spectra are reported and vibrations originating
from Si–Si inter‐cluster bonds as well as Si‐C exo‐bonds are assigned by comparison to calculated
(DFTPBE0) spectra.
References 1. Charged Si9 Clusters in Neat Solids and Solution – A Combined NMR, Raman, Mass Spectrometric, and Quantum
Chemical Investigation.
L. J. Schiegerl, A. J. Karttunen, J. Tillmann, S. Geier, G. Raudaschl-Sieber, M. Waibel, T. F. Fässler,
Angew. Chem. Int. Ed. 57 (2018) 12950 –12955.
2. Silicon Containing Nine Atom Clusters from Liquid Ammonia Solution: Crystal Structures of the First Protonated Clusters
[HSi9]3– and [H2{Si/Ge}9]2–
T. Henneberger, W. Klein, T. F. Fässler
Z. Anorg. Allg. Chem. 644 (2018) 1018-1027
3. Anionic Siliconoids from Zintl Phases: R3Si9- with Six and R2Si9
2− with Seven Unsubstituted Exposed Silicon Cluster Atoms
(R = Si(tBu)2H)
L. J. Schiegerl, A. J. Karttunen, W. Klein, T. F. Fässler
Chem. Eur. J. 24 (2018) 19171–19174
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Comparison of Reactivity towards Acyl Chlorides among an Isolable Dialkylsilylene and Its Germanium and Tin Congeners
Huaiyuan Zhu, Xupeng Liu, Chenting Yan, Qiong Lu, Ningka, Wei, Xu-Qiong Xiao, Zhifang Li, and Mitsuo Kira
Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Hangzhou
Normal University, Hangzhou 311121, P. R. China
mitsuo.kira.e2@ tohoku.ac.jp
Though insertion reactions of tetrylenes into various C-Cl bonds offer a useful technique for
derivatization of the tetrylenes, generally, the reaction mechanisms are not simple or straightforward.
We have recently reported that when isolable dialkyltetrylenes 1a -1c are treated with an equimolar
amount of (4-substituted)benzoyl chlorides 2 in hexane or THF at room temperature, the corresponding
benzoyl(chloro)tetrylenes 3 are obtained in high yields, indicating that the C–Cl bond is much more
reactive than the carbonyl group (Eq. (1)).1-3
In contrast, the reactivity towards simple alkanoyl chlorides is very dependent on the tetrylenes.3 As
shown in Scheme 1, typically, the reaction of germylene 1b with acetyl chloride gives a mixture of the
corresponding acetyl(chloro)germane, diacetylgermane, and dichlorogermane, while related reactions
with silylene 1a and stannylene 1c give a complex mixture and dichlorostannane, respectively. While
remarkable difference of the reactivity among tetrylenes 1a-1c is suggestive of the radical nature of the
reactions, the reaction mechanisms remain open.
Scheme 1. Diverse Reactions of Tetrylenes 1a-1c with Simple Alkanoyl Chlorides.
Interestingly, diakanoylgermanes 5 show two separated n(O)→ π*(C=O) bands at 350 and 400 nm
in the UV/Vis spectra. The origin will also be discussed.
References
1. Xiao, X.-Q.; Liu, X.; Lu, Q.; Li, Z.; Lai, G.; Kira, M. Molecules 2016, 21, 1376.
2. Lu, Q.; Yan, C.; Xiao, X.-Q.; Li, Z.; Wei, N.; Lai, G.; Kira, M. Organometallics 2017, 36, 3633.
3. Zhu, H.; Wei, N.; Li, Z.; Yang, Q.; Xiao, X.-Q.; Lai, G.; Kira, M. Organometallics 2019, 38, 1955.
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Silicon Bond: Interaction to Form Micelles in a LC Phase
Soichiro Kyushin,a,* Kenji Nanba,a Kimio Yoshimura,b Yue Zhao,b Yasunari Maekawab
aGraduate School of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan bTakasaki Advanced Radiation Research Institute, National Institutes for Quantum and Radiological Science
and Technology, Takasaki, Gunma 370-1207, Japan
Liquid crystal molecules consist of rigid central cores and flexible side chains. Recenty, we have
reported that a silyl group bearing two hydrogen atoms and a long alkyl group works as a flexible side
chain.1 For example, 4-hexyloxy-4’’-pentylsilyl-p-terphenyl (1: R1 = R2 = H) shows a SmA phase, in
which rod-like molecules are arranged in a parallel mannar.
When the two hydrogen atoms of the silyl group are replaced by methyl groups, the liquid crystalline
phase is dramatically changed to an unusual phase. The liquid crystalline phase observed with a
polarizing microscope does not show a usual liquid crystalline texture but a dark field. Reflections were
observed only by small-angle X-ray scattering. These results and other data show that the liquid
crystalline phase is isotropic cubic phase, in which molecules are arranged in a head-to-head manner to
form micelles. Theoretical calculations indicate that driving force to form this phase is intermolecular
electrostatic interaction between the negatively charged methyl groups and the positively charged
silicon atoms. This interaction resembles the hydrogen bond and can be regarded as the silicon bond.
This bond is cleaved by further replacement of the methyl groups by ethyl, propyl, and pentyl groups
to lead a SmB phase, in which molecules are arranged in a head-to-tail manner.
Figure 1. Molecular arrangement in the liquid crystalline phases of 4-hexyloxy-4’’-silyl-p-terphenyls.
Reference
1. Otsuka, K.; Ishida, S.; Kyushin, S. Chem. Lett. 2012, 41, 307–309.
R1 = R2 = H R1 = H, R2 = Me
R1 = R2 = Me
R1 = R2 = Et (25 C) R1 = R2 = PeR1 = R2 = Et (55 C)
R1 = R2 = Pr (25 C)
liquid
1
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Improved synthesis and reactivity of the
tris(pentafluoroethyl)silanide ion
Natalia Tiessen, Nico Schwarze, Berthold Hoge*
Bielefeld University, Center for Molecular Materials, 33615 Bielefeld, Germany,
The literature-known synthesis of tris(pentafluoroethyl)silanide salts1 proceeds via the deprotonation
of Si(C2F5)3H, which is synthesized via four steps:2
The reaction of commercially available SiCl3H with in situ generated LiC2F5 3 allows an access of
Si(C2F5)3H within one step. The subsequent treatment of the resulting Et2O solution with neutral
phosphazene bases R3P=NtBu (R = -N=P(NEt2)3 and -NC(NMe2)2) leads to a two-step synthesis of the
corresponding [R3PN(H)tBu]+[Si(C2F5)3]- salts.
The [Si(C2F5)3]- ion exhibits Lewis amphoteric character and adds carbonyl derivatives side-on. An
intermediary addition of CO2 leads to a liberation of CO and a dimerization of the resulting silanolate
ions.
References
1. N. Schwarze, S. Steinhauer, B. Neumann, H.-G. Stammler, B. Hoge, Angew. Chem. 2016, 128, 16390-16394. N. Schwarze,
S. Steinhauer, B. Neumann, H.-G. Stammler, B. Hoge, Angew. Chem., 2016, 128, 16395-16398.
2. S. Steinhauer, J. Bader, H.-G. Stammler, N. Ignat'ev, B. Hoge, Angew. Chem., 2014, 126, 5307- 5310
3. M. Heinrich, A. Marhold, A. Kolomeitsev, A. Kadyrov, G.-V. Röschenthaler, J. Barten (Bayer AG), DE 10128703A 1,
2001; M. H. Königsmann, Dissertation, Universität Bremen, 2005; A. A. Kolomeitsev, A. A. Kadyrov, J. Szczepkowska-
Sztolcman, H. Milewska, G. Bissky, J. A. Barten, G.-V. Röschenthaler, Tetrahedron Lett. 2003, 44, 8273–8277
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Power of Silyl-substituents: From Cyclobutadiene Dianion to
Cyclobutadienes, Tetrahedranes, and Pyramidanes
Akira Sekiguchia,b,*
aDepartment of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba,
Ibaraki 305-8571, Japan
bInterdisciplinary Research Center for Catalytic Chemistry, National Institute of Advanced Industrial Science
and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
[email protected]; [email protected]
The chemistry of the cyclobutadiene (CBD) and tetrahedrane (THD) was long a fascinating target for
both synthetic and computational chemists. In this symposium, the chemistry of the silyl-substituted
cyclobutadienes, tetrahedranes, and the related compounds such as pyramidanes, derived from the
cyclobutadiene dianion will be reported.
The dilithium salt of tetrakis(trimethylsilyl)cyclobutadiene dianion [(Me3Si)4C4]2–•2Li+ (1)
underwent two electron oxidation, giving the tetrakis(trimethylsilyl)cyclobutadiene [(Me3Si)4CBD] (2),
which was then converted to the tetrakis(trimethylsilyl)tetrahedrane (Me3Si)4THD (3), in which the four
trimethylsilyl groups sterically and electronically stabilize the skeleton of 3. Furthermore,
functionalization of 3 through the desilylation–metalation allowed for the preparation of the
tris(trimethylsilyl)tetrahedranyllithium (Me3Si)3THD-Li (4), which opened the way to new members of
tetrahedrane family. We have also extended the palladium-catalyzed cross-coupling reaction of 4 with
aryl halides, forming various aryl-substituted tetrahedrane derivatives (5), which were photochemically
isomerized to the corresponding cyclobutadiene derivatives Ar(Me3Si)3CBD (6). Moreover, a new class
of polyhedral compounds, pyramidanes (7), with C4-bases and Ge or Sn atoms at the apex of the square-
pyramid, was recently prepared by the reaction of 1 with ECl2 (E = Ge, Sn). The peculiar structural and
bonding features of these compounds were verified by combined experimental and computational
studies.
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Formation of 1,2- and 1,4-Disilabenzenes
Takahiro Sasamori,a,* Tomohiro Sugahara,b Norihiro Tokitoh,b Jing-Dong Guo,a,b Shigeru Nagase,c and Daisule Hashizumed
a Graduate School of Natural Sciences, Nagoya City University, Yamanohata 1, Mizuho-cho, Mizuho-ku,
Nagoya, Aichi 467-8501, JAPAN. b Institute for Chemical Research, Kyoto Univ., Gokasho, Uji, Kyoto 611-0011, JAPAN.
c Fukui Institute for Fundamental Chemistry, Kyoto Univ., Sakyo-ku, Kyoto 606-8103, JAPAN. d RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama 351-0198, JAPAN.
In contrast to the wealth of physical functionality of benzene, chemically it is generally inert due to
considerable aromatic stabilization energy. However, replacing a C-H moiety of benzene with a heavier
main-group moiety significantly affects the physical and chemical properties of the cyclic-π- conjugated
systems.1 Therefore, we are interested in the replacement of C–H moieties with moieties that contain
heavier group 14 elements (E–R; E = Si, Ge, Sn, or Pb; R = organic substituent) in order to control the
physical and chemical properties. Since Sekiguchi et al. have reported the synthesis of the first stable
1,2-disilabenzenes by the reaction of the stable disilyne, the chemistry of 1,2-dimetallabenzenes have
been developed.2 Recently, we have reported the synthesis of the stable 1,2- and 1,4-digermabenzenes
by the analogous reactions, i.e., the reaction of the diaryldigermyne with alkynes. However, a 1,4-
disilabenzene is still hitherto unknown even though several efforts of attempted syntheses. Herein, we
report the synthesis of stable 1,2- and 1,4-disilabenzenes by the reactions of the stable diaryldisilyne,
TbbSi ≡ SiTbb (Tbb = 2,6-[CH(SiMe3)2]2-4-t-Bu-C6H2), with terminal- and internal-alkynes.3 The
reaction formation mechanism of the 1,2- and 1,4-disilabenzenes will also be discussed.
Scheme 1. Reactions of the diaryldisilyne with alkynes to give 1,2- or 1,4-disilabenzenes.
References
1. Tokitoh, N. Acc. Chem. Res. 2004, 37, 86–94; Nagase, S. Bull. Chem. Soc. Jpn. 2014, 87, 167–195.
2. Sugahara, T.; Guo, J.-D.; Sasamori, T.; Karatsu, Y.; Furukawa, Y.; Espinosa Ferao, A.; Nagase, S.; Tokitoh, N., Bull.
Chem. Soc. Jpn. 2016, 89, 1375-1384; Sasamori, T.; Sugahara, T.; Agou, T.; Guo, J.-D.; Nagase, S.; Streubel, R.; Tokitoh,
N., Organometallics 2015, 34, 2106-2109; Sugahara, T.; Guo, J.-D.; Hashizume, D.; Sasamori, T.; Tokitoh, N., J. Am.
Chem. Soc. 2019, 141, 2263-2267.
3. Sugahara, T.; Guo, J.-D.; Hashizume, D.; Sasamori, T.; Nagase, S.; Tokitoh, N. Dalton Trans. 2018, 47, 13318-13322;
Sugahara, T.; Sasamori, Tokitoh, N. Dalton Trans., in press [doi: 10.1039/C9DT01322A].
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Recent Development of Janus Siloxanes
Masafumi Unno,*,a.b Yujia Liu,b Naoki Oguri,a Chika Kobuna,a Mana Kigure,a,b Taishi Uchida,a Ryoji Tanaka,a Kazunori Asami,a Thanawat Chaiprasert,a Yasunobu
Egawa,a Nobuhiro Takedaa
a Department of Chemistry and Chemical Biology, Faculty of Science and Technology, Gunma University, Kiryu
376-8515, Gunma, Japan b Gunma University Initiative for Advanced Research (GIAR) - International Open Laboratory with Montpellier
France – Institute Charles Gerhardt (CNRS/ENSCM/UM)
In the field of materials science, well-defined silsesquiixanes have recently attracted significant
attention. Among them, cage octasilsesquioxane or T8 is nano-scale organic/inorganic hybrid molecules,
with an inorganic core and eight organic substitutions in a single molecule. In 2016, we reported the
synthesis and structure determination of Janus cube that is a cage octasilsesquioxane possessing two
different substituents on the opposite face.1 Following this Janus Cube (1st gen.), we then extended the
investigation on Janus cube with reactive substituents (2nd gen.), and those with larger framework (3rd
gen.).2 In all cases we successfully determined the structures by X-ray crystallography, and revealed
their properties.
In addition, we also succeeded in the synthesis of small Janus cage silsesquioxesanes with T6
framework. We named it Janus prism. Introduction of disilane moiety to this Janus prism drastically
alters their electronic properties.
In this presentation, we also report Janus ring, that was first introduced by Bassindale and Taylor
group,3 and show their reaction to afford laddersiloxanes.4
Scheme 1. Janus cubes, prisms, rings, and Lantern cage
References
1. Oguri, N.; Egawa, Y.; Takeda, N.; Unno, M. Angew. Chem., Int. Ed. 2016, 55, 9336−9339.
2. Uchida, T.; Egawa, Y.; Adachi, T.; Oguri, N.; Kobayashi, M.; Kudo, T.; Takeda, N.; Unno, M.; Tanaka, R. Chem. Eur. J.
2019, 25, 1683-1686.
3. Panisch, R.; Bassindale, A. R.; Korlyukov, A. A.; Pitak, M. B.; Coles, S. J.; Taylor, P.G. Organometallics, 2013, 32, 1732–
1742
4. Presented in the poster session in this symposium by Thanawat Chaiprasert et al.
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Transision Metal-Catalyzed Precise Synthesis of Organosilicon
Compounds Starting from Halosilanes
Yumiko Nakajima, Yuki Naganawa, Kazuhiko Matsumoto, Teruo Beppu, Kazuhiko Sato, Shigeru Shimada
Interdisciplinary Research Center for Catalytic Chemistry
National Institute of Advanced Industrial Science and Technology (AIST)
Tsukuba, Ibaraki 305-8565, Japan
Chlorosilanes are cheap and readily available silicon feedstocks produced by Müller–Rochow
“Direct Process”. Various useful organosilicon compounds are commonly prepared from chlorosilanes
via introduction of organic substituents on the silicon atom using stoichiometric organometallic species
such as organolithium or Grignard reagents. Meanwhile, transition metal-catalyzed cross coupling
approaches via Si–X bond activation of halosilanes have drawn increasing attention for the purpose of
new Si–C bond formations.1 Especially, catalytic transformation of a Si–Cl bond is still challenging due
to higher bond strength (Si–Cl: 98 kcal/mol) compared to those of other halosilanes (Si−Br: 76 kcal/mol,
Si−I: 57 kcal/mol).
In this study, we have demonstrated the first example of direct silyl-Heck reaction of chlorosilanes
using the Ni catalyst with an electron donating PCy3 ligand (Scheme 1).2 Interestingly, highly selective
mono-alkenylation of di- or trichlorosilanes were achieved.
Scheme 1. Ni-catalyzed Alkenylation of Me2SiCl2
Hydrogenolysis of various halosilanes was also examined. By using iridium amido complexes as
catalysts, hydrogenolysis of various halosilanes were achieved to produce the corresponding
hydrosilanes.3 Interestingly, selective monohydrogenolysis of di- and trichlorosilanes similarly
proceeded, resulting in the formation of chlorohydrosilanes (R2SiHCl or RSiHCl2) as synthetically
important building blocks for various functionalized silicones.
Scheme 2. Ir-catalyzed Hydrogenolysis of Halosilanes
References
1. B. Vulovic, D. A. Watson Eur. J. Org. Chem. 2017, 4996.; A. P. Cinderella, B. Vulovic, D. A. Watson, J. Am. Chem. Soc.
2017, 139, 7741.; B. Vulovic, A. P. Cinderella, D. A. Watson, ACS Catal. 2017, 7, 8113.
2. K. Matsumoto, J. Huang, Y. Naganawa, H. Guo, T. Beppu, K. Sato, S. Shimada, Y. Nakajima, Org. Lett., 2018, 20, 2481.;
Y. Naganawa, H. Guo, K. Sakamoto, Y. Nakajima, ChemCatChem. In press.
3. T. Beppu, K. Sakamoto, Y. Nakajima, K. Matsumoto, K. Sato, S. Shimada, J. Organomet. Chem. 2018, 869, 75.
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Silsesquioxanes-Based Multifunctional Porous Polymers
Hongzhi Liu
School of Chemistry and Chemical Engineering, Shandong University, China
Research on porous materials has developed explosively, as indicated by extensive increases in the
number of publications. Recently, more attention has been devoted to hybrid porous polymer
considering their exhibiting some unique properties by combination with the advantages of inorganic
and organic components. Cage silsesquioxanes have proven to be an ideal building block to prepare
hybrid nanoporous polymers with enhanced thermal and mechanical properties in view of their rigidity
and multifunctionality.1,2
Very recently, octavinylsilsesquioxane (OVS) has been successfully used to prepare silsesquioxanes-
based porous materials via Friedel-crafts reaction and Heck reaction, cationic polymerization by us.3-5
These silssesquioxanes-based porous polymers exhibited high surface area and thermal stability, even
excellent luminescence, which make them multifunctional and potentially apply in gas storage, water
treatment, energy storage and sensors etc.
References:
1. Furgal, J. C.; Jae Hwan, J.; Theodore, G.; Laine, R. M. Analyzing Structure-Photophysical Property Relationships for
Isolated T8, T10, and T12 Stilbenevinylsilsesquioxanes. J. Am. Chem. Soc. 2013, 135, 12259-12269.
2. Watcharop, C.; Masaru, K.; Takahiko, M.; Ayae, S. N.; Atsushi, S.; Tatsuya, O. Porous Siloxane-Organic Hybrid with
Ultrahigh Surface Area Through Simultaneous Polymerization-Destruction of Functionalized Cubic Siloxane Cages. J.
Am. Chem. Soc. 2011, 133, 13832-13835.
3. Yang, X.; Liu, H. Ferrocene-Functionalized Silsesquioxane-Based Porous Polymer for Efficient Removal of Dyes and
Heavy Metal Ions. Chem. Eur. J. 2018, 24, 13504-13511.
4. Ge, M.; Liu, H. A Silsesquioxane-Based Thiophene-Bridged Hybrid Nanoporous Network as A Highly Efficient
Adsorbent for Wastewater Treatment. J. Mater. Chem. A. 2016, 4, 16714-16722.
5. Y. Du, M. Ge, H. Liu, Porous Polymers Derived from Octavinylsilsesquioxane by Cationic Polymerization. Macromol.
Chem. Phys. 2019, 220, 1800536-1800543.
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Cobalt-Catalyzed Selective Hydrosilylation of Unsaturated
Hydrocarbons
Shaozhong Ge*
Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore
Organosilanes are valuable reagents in organic synthesis due to their high stability and low toxicity.
The research in my group at National University of Singapore (NUS) focuses on the development of
base metals (Fe, Co, Ni, and Cu) catalyzed hydrofunctionalization of unsaturated hydrocarbons to
access these synthetically versatile oragnoboron compounds1-7 and organosilanes.8-12 In this
presentation, I will discuss a series of regio-, stereo-, or enantioselective cobalt-catalyzed
hydrosilylation of alkenes, alkynes, allenes, enynes, and conjugated dienes (Figure 1). The cobalt
catalysts are generated in situ from bench stable cobalt precursors and bisphosphine ligands. The scope
and mechanism of these reactions will be discussed.
Figure 1. Cobalt-Catalyzed Hydrosilylation of Unsaturated Hydrocarbons to Prepare Organosilanes
References
1. Wang, C.; Wu, C.; Ge, S. ACS Catal. 2016, 6, 7585–7589.
2. Yu, S.; Wu, C.; Ge, S. J. Am. Chem. Soc. 2017, 139, 6526–6529.
3. Teo, W. J.; Ge, S. Angew. Chem., Int. Ed. 2018, 57, 1654–1658.
4. Sang, H. L.; Yu, S.; Ge, S. Org. Chem. Front. 2018, 5, 1284–1287.
5. Teo, W. J.; Ge, S. Angew. Chem., Int. Ed. 2018 57, 12939–12939.
6. Wang, C.; Ge, S. J. Am. Chem. Soc. 2018, 140, 10687–10690.
7. Wu, C.; Liao, J.; Ge, S. Angew. Chem., Int. Ed. 2019 58, doi:10.1002/anie.201903377.
8. Wu, C.; Teo, W. J.; Ge, S. ACS Catal. 2018, 8, 5896–5900.
9. Sang, H. L.; Yu, S.; Ge, S. Chem. Sci. 2018, 9, 973–978.
10. Wang, C.; Teo, W. J.; Ge, S. Nat. Commun. 2017, 8, 2258.
11. Teo, W. J.; Wang, C.; Tan, Y. W.; Ge, S. Angew. Chem., Int. Ed. 2017, 56, 4328–4332.
12. Wang, C.; Teo, W. J.; Ge, S. ACS Catal. 2017, 7, 855–863.
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Bridged Polysilsesquioxane Membranes for Water Desalination
Joji Ohshita
Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University
Higashi-Hiroshima 739-8527, JAPAN
Bridged polysilsesquioxane (PSQ) membranes prepared by the sol-gel process of organically bridged
trialkoxysilanes, [(R’O)3SiRSi(OR’)3], have been reported as promising precursors of robust separation
membranes. They usually show high permeability compared to silica or non-bridged PSQ membranes,
because the organic bridges expand the siloxane network as a “spacer” to enhance porosity. Previously,
we reported that PSQs prepared from bis(triethoxysilyl)ethane (BTESE1 in Chart 1) could be used for
robust RO membranes because of their high chlorine tolerance and thermal stability of up to 90 °C.1
However, the liquid permeability is much lower than that of commercially available polyamide
membranes. In our efforts to improve the water permeability, we found that the introduction of
ethenylene and ethynylene units in place of the ethylene bridge increased the water permeability by
increasing the rigidity and polarity of the bridges (BTESE2 and BTESE3).2
Preparation of bridged PSQ RO membranes from other bridged silica precursors in Chart 1 will be
also described.
Chart 1. Chemical structures of bridged alkoxysilanes precursors for water desalination membranes
References
1. Ibrahim, S. M.; Xu, R.; Nagasawa, H.; Naka, A.; Ohshita, J.; Yoshioka, T.; Kanezashi, M.; Tsuru, T. RSC Adv. 2014, 4,
23759–23769.
9. Xu, R.; Kanezashi, M.; Yoshioka, T; Okuda, T; Ohshita, J; Tsuru, T ACS Appl. Mater. Interfaces 2013, 5, 6147–6154; Xu,
R.; Ibrahim, S. M.; Kanezashi, M.; Yoshioka, T.; Ito, K.; Ohshita, J.; Tsuru, T. ACS Appl. Mater. Interfaces 2014, 6, 9357–
9364.
10. Yamamoto, K.; Ohshita, J.; Mizumo, T.; Kanezashi, M.; Tsuru, T. Sep. Purif. Technol. 2015, 156, 396-402
11. Zheng, F.-T.; Yamamoto, K.; Kanezashi, M.; Tsuru, T.; Ohshita, J. J. Membr. Sci. 2018, 546, 173-178.
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Boron Cation Catalyzed Hydrosilylation and Cyanosilylation
Hsi-Ching Tseng, Yen-Tzu Huang, Ching-Wen Chiu*
Department of Chemistry, National Taiwan University, Taipei, Taiwan 10617
Hydrosilylation and cyanosilylation are important synthetic strategies for organosilicon derivatives.
In addition to transition metal-based catalysts, recent studies have showed that such catalytic
transformation could be performed with Lewis acid p-block compounds as well. Given the fact that
tricoordinate boron derivatives are prototypical Lewis acidic catalyst for versatile organic synthesis,
halogenated boranes have been examined for catalytic silylation reactions. As the library of neutral
boron catalyst continues to expand, boron cation catalysis has also emerged in the past few years.
Besides the well-established oxazaborolidine-type catalysts, carbene and pyridine stabilized
tricoordinate borenium cations are effective catalysts for hydrogenation of imine, hydrosilylation of
carbonyl compounds, and hydroboration of alkene.1 However, catalytic activity of other types of boron
cations is less explored. During our study of Cp*-subsituted boron cations, we came to discovered that
the central hypercoordinate boron atom remains highly acidic.2 [Cp*B-R]+ cation can be viewed as a
masked potent Lewis acid that serves as an efficient catalyst for hydrosilylation and cyanosilylation of
carbonyl compounds. The steric and electronic stabilization effects of Cp* were found to be critical in
realizing robust boron cation catalyst. In this presentation, experimental details and mechanistic studies
of the [Cp*B-R]+ catalyzed hydrosilylation and cyanosilylation will be discussed.
Figure 1. Proposed reaction mechanism for [Cp*B-Mes]+ catalyaed hydrosilylation/hydrodeoxygenation of ketone.
References
1. Einsenberger, P.; Crudden, C. M. Dalton Trans. 2017, 46, 4874.
12. Tseng, H.-C.; Shen, C.-T.; Matsumoto, K.; Liu, Y.-H.; Peng, S.-M.; Yamaguchi, S.; Chiu, C.-W. to be submitted.
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Soluble Silicon Materials for 193 nm Lithography and Capacitor
Fabrication
Hyeon Mo Cho
University College, Yonsei University, Incheon 21983, South Korea
(past: Samsung SDI, Suwon, Gyeonggi, 16698, South Korea)
The progress of semiconductor fabrication technology to create more integrated circuits and
nanosized patterns provides us innovative electrical and electronic devices. Since the fabrication is a
multiple-step sequence of photolithographic and chemical processing steps, a variety of chemicals and
new materials are demanded. In semiconductor manufacturing, there are essential silicon materials,
such as silicon substrates, silicon oxide and silicon nitride. Lithography, which specifically includes
light exposure, etching, and developing processes, requires silicon materials that are photosensitive to
light sources and have etch selectivity for plasmas. For example, the spin-on hardmask (SOH) process
requires a silicon material with specific optical and etch properties. Silicon material of SOH process
plays a dual role: as an anti-reflective layer for proper photoresist patterning in the exposure step, which
requires specific optical properties and as a hardmask layer for pattern transfer to a layer below during
the etch step, which is ensured by the high etch resistance to oxygen plasma. The advantage of spin
coating is its ability to quickly and easily produce very uniform films with good planarity and fill
trenches with a high aspect ratio. In order to apply to the spin coating process, the material must be in
a liquid state or well dissolved in a solvent.
In this presentation, the synthesis and application of soluble silicon materials absorbing 193 nm light
for nanosized patterning (Figure 1) and a developable silicon material for capacitor manufacturing will
be discussed.
Figure 1. Preparation of silicon thin films from a new class of soluble polycyclosilane-polysiloxane hybrid materials.
IL – 13
Nanyang Technological University
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Synthesis of trialkylsilylboranes through Rh-catalyzed borylation
of trialkylsilanes and generation of a broad range of trialkysilyl
nucleophiles
Hajime Ito,a,b* Ryosuke Shishido,b Minami Uesugi, b Koji Kubota a,b
aGraduate School of Engineering, Hokkaido University, Sapporo, 060-8628, Japan bWPI-ICReDD, Hokkaido University, Sapporo, 001-0021, Japan
Silyl anion is a fundamental species in silicon chemistry and was focused by many researchers for a
long time. The generation of silyl anion highly depends on the reduction of chlorosilanes and disilanes.
However, this method requires at least one aromatic substituent on the silicon atom to enable the
formation of the silyl anion. Other methods through transmetallation from silyl mercury and silyl tin
compounds are also known but were not widely used due to the high toxicity of the precursors. In
general, generation of trialkyl silyl anion with the practically applicable method is still an unsolved
issue in silicon chemistry. In 2001, Kawauchi and Tamao first reported the generation of silyl
nucleophiles from non-toxic silylborane compounds in the reaction with nucleophiles such as MeLi,
KOtBu.1 We also reported the first silylboration of styrene compounds with silylborane/KOtBu in
2012.2,3 This is a promising method for generation of silyl anions, but the synthesis of silylboranes is
still limited: many silylboranes are synthesized from silyl anions. In 2008, Hartwig reported an Ir-
catalyzed synthesis of trialkylsilylboranes.4 Et3SiB(pin) was synthesized from Et3SiH and B2(pin)2
without generation of elaborating trialkylsilyl anion. The combination of borylation of trialkylsilanes
and nucleophile-catalyzed activation of silylboranes can be an excellent complemental method of
conventional production of silyl anions, but the narrow scope of the Hartwig method limits this
procedure.
In this work, we developed a rhodium-catalyzed Si–H borylation of hydrosilanes for the
synthesis of silylborane compounds. This new method can synthesize silylboranes that could not be
obtained by previous means. Various hydrosilanes, including bulky hydrosilanes, underwent the
borylations effectively to give the corresponding silylboranes in good yield. Furthermore, the synthesis
of oligosilanes using the Si-Si coupling reactions of various silylboranes with silyl electrophiles was
achieved.
Figure 1. Rh-catalyzed Borylation of Hydrosilane and MeLi-mediated Si-Si bond Formation.
References
1. Kawachi, T. Minamimoto, K. Tamao, Chem. Lett. 2001, 30, 1216-1217.
2. H. Ito, Y. Horita, E. Yamamoto, Chem. Commun. 2012, 48, 8006-8008
3. (a) E. Yamamoto, K. Izumi, Y. Horita, H. Ito, J. Am. Chem. Soc. 2012, 134, 19997-20000; (b) E. Yamamoto, S. Ukigai,
H. Ito, Chem. Sci. 2015, 6, 2943-2951; (c) R. Uematsu, E. Yamamoto, S. Maeda, H. Ito, T. Taketsugu, J. Am. Chem. Soc.
2015, 137, 4090-4099; (d) E. Yamamoto, K. Izumi, R. Shishido, T. Seki, N. Tokodai, H. Ito, Chem. Eur. J. 2016, 22,
17547-17551. (e) C. Kleeberg, C. Borner, Eur. J. Inorg. Chem. 2013, 2799-2806; (f) B. Cui, S. Jia, E. Tokunaga, N.
Shibata, Nat. Commun. 2018, 9, 4393-4400; (g) X.-W. Liu, C. Zarate, R. Martin, Angew. Chem. Int. Ed. 2019, 58, 2064-
2068; (h) K. Kojima, Y. Nagashima, C. Wang, M. Uchiyama, ChemPlusChem 2019, 84, 277-280.
4. T. A. Boebel, J. F. Hartwig, Organometallics 2008, 27, 6013-6019.
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Fabrication and Application of Hollow Multi-Au@SiO2
Nanosystems, and Nanohybrids with Coordination Polymer
Framework Derivatives
Hyojong Yoo
Department of Chemistry, Hallym University, Chuncheon, Gangwon-do, 24252, Republic of Korea
Advanced hybrid nanomaterials tailored with unique morphologies and multiple functions can be
fabricated by the rational combination of two or more well-designed components. We report facile
synthetic strategies for metallic nanostructures/silica/polymeric framework nanohybrids. The material
properties (i.e., surface area, size, and shape) of the resultant nanohybrids can be readily controlled by
simply varying reaction kinetics and the relative amount of precursors used. The as-synthesized
nanohybrids can act as sacrificial templates for the preparation of unique inorganic nanomaterials via
chemically- and thermally-induced approaches, which can be applied for a variety of area.1
Spherical nanoparticles (multi-Au@SiO2 NPs) and nanowires (multi-Au@SiO2 NWs) with a core
comprising multiple Au nanodots and silica shell are fabricated in high yields through reverse (water-
in-oil) microemulsion-based methods. By simple treatments, york-shell multi-Au@SiO2 NPs and
peapod-like one-dimensional Au nanoparticles array within hollow silica nanotubes (pp multi-
Au@SiO2 NTs) can be successfully synthesized.2 These hollow multi-Au@SiO2 nanosystems can be
used as efficient nanoreactors for fabrication of hybrid nanoparticles assembly and catalysis.
Gold multipod nanoparticle (GMN) core–zeolitic imidazolate framework (ZIF-67) shell
(GMN@ZIF-67) nanohybrids can be successfully synthesized.3 The as-prepared GMN@ZIF-67
nanohybrids can be the precursors for the preparation of GMN core–cobalt sulfide shell (GMN@CoxSy)
nanostructures, with unique cage-like morphology.4 The examination of electrocatalytic oxygen
evolution reaction (OER) of the prepared nanohybrids reveals that a type of GMN@CoxSy nanohybrids
shows a substantially lower overpotential value compared with those of GMNs and CoxSy nanomaterials.
We also report a shape-controllable synthetic protocol for zinc-based coordination polymer nanocubes
(Zn-CPNs).5 2,6-bis[(4-carboxyanilino)carbonyl] pyridine ([N3]) ligand is employed as an efficient
shape-directing modulator to control the size and shape of Zn-CPNs. More importantly, the [N3] ligand
provides metal binding sites suitable for the decoration of other functional metals such as copper ions.
The copper-modified Zn-CPNs (Cu_Zn-CPNs) show good activities in a heterogeneous catalytic
reaction.
Mesoporous silica nanoparticles, which have high surface areas and an abundance of pores, can be
used to synthesize mesoporous silica core–metal shell nanostructures with catalytically active sites.
Highly fluorescent multiple Fe3O4 nanoparticles core-silica shell nanoparticles (FL multi-Fe3O4@SiO2
NPs) are successfully synthesized and fully characterized.6 In addition, dendritic fibrous nanosilica
(DFNS) with a high surface area is successfully employed as a template to synthesize DFNS/MOF,
DFNS/Au, and DFNS/Au/MOF hybrid nanomaterials.7
References
1. Mai, H. D.; Rapiq, K.; Yoo, H. Chem. Eur. J. 2017, 23, 5631.
2. Byoun, W.; Yoo, H. ChemistrySelect. Eur. J. 2017, 2, 2414.
3. Mai, H. D.; Le, V. C. T.; Thi, M. T. P.; Yoo, H. ChemNanoMat 2017, 3, 857.
4. Mai, H. D.; Le, V. C. T.; Yoo, H. ACS Appl. Nano Mater 2019, 2, 678.
5. Ngoc, T. M.; Mai, H. D.; Yoo, H. Nano Research 2018, 11, 5890.
6. Byoun, W.; M. G. Jang.; Yoo, H. J. Nanopart. Res. 2019, 21, 1.
7. Byoun, W.; Jung, S.; Ngoc, T. M.; Yoo, H. ChemistryOpen 2018, 7, 349.
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Silicon-Mediated Organic Synthesis (SiMOS): Silicon-Substitution
Effect (SiSE) in Asymmetric Catalysis
Li-Wen Xu
Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, and Key
Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, P. R.
China
In the past decades, organosilicon compounds are finding important and new applications in organic
synthesis, such as the effective application of organosilicon compounds in the transition metal-catalyzed
cross-coupling reactions, the syntheses and application of silicon-stereogenic organosilicon compounds,
the silicon-containing organocatalysts or chiral ligands, silicon-based Lewis acids in catalytic organic
transformation, and the use of silanes and its functional materials as stoichiometric reductants in a range
of chemo-, stereo-, and enatioselective catalytic reductions. Undoubtedly, the unabated growth of
applications of organosilicon compounds and related materials in the resolution of synthetic problems
has continued.
Figure 1. SiMOS: From Organosilicon-Enhanced Asymmetric Catalysis to the Synthesis of Silicon-Stereogenic Molecules
Herein, we would like to present our effort in the exploring of organosilicon compounds and related
silicon-based functional organic materials as reagents, catalysts, and supporter for various organic
transformations in asymmetric catalysis.1-11 Our exploration could be expected to lead to continuing
research on wide exploration of organosilicon compounds and related materials for the establishment
of highly efficient and stereoselective transformations, aiming to develop new approach and strategy
for the facile preparation of synthetically useful molecules with environmentally benign and practical
procedure.
References
1. Xu, L.-W.; Li, L.; Lai, G.-Q.; Jiang, J.-X. Chem. Soc. Rev. 2011, 40, 1777-1790.
2. Xu, L.-W. Angew. Chem. Int. Ed. 2012, 51, 12932-12934.
3. Ye, F.; Zheng, Z. J.; Li, L.; Yang,K. F.; Xia, C. G.; Xu, L.-W. Chem. Eur. J. 2013, 19, 15452-15457.
4. Bai, X.-F.; Deng, W.-H.; Xu, Z.; Li, F.-W.; Deng, Y.; Xia, C.-G.; Xu, L.-W. Chem. Asian. J. 2014, 9, 1108-1115.
5. Song, T.; Li, L.; Zhou, W.; Zheng, Z.-J.; Deng, Y.; Xu, Z.; Xu, L.-W. Chem. Eur. J. 2015, 21, 554-558.
6. Xu, L.-W.; Chen, Y.; Lu, Y. Angew. Chem. Int. Ed., 2015, 54, 9456–9466.
7. Lin, Y.; Jiang, K.-Z.; Cao, J.; Zheng, Z.-J.; Xu, Z.; Cui, Y.-M.; Xu, L.-W. Adv. Synth. Catal. 2017, 359, 2247-2252.
8. Cramm, N. T. U.S. Patent 7,005,423, Sep 13, 2005.
9. Mu, Q.-C.; Wang, X.-B.; Ye, F.; Sun, Y.-L.; Bai, X.-F.; Chen, J.; Xia, C.-G.; Xu, L.-W. Chem. Commun., 2018, 54, 12994-
12997.
10. Long, P.-W.; Bai, X.-F.; Ye, F.; Li, L.; Xu, Z.; Yang, K.-F.; Cui, Y.-M.; Zheng, Z.-J.; Xu, L.-W. Adv. Synth. Catal. 2018,
360, 2825-2830.
11. Cao, J.; Chen, L.; Sun, F.-N.; Sun, Y.-L.; Jiang, K.-Z.; Yang, K.-F.; Xu, Z.; Xu, L.-W. Angew. Chem. Int. Ed. 2019, 58,
897 –901.
SiMOSSi-Reagent
Si-Additive Si-Catalyst
Sakurai Reaction
Silicon-stereogenic Silanes
Allylation/etherification
Huisgen and Oxidative HuisgenOxidative Esterification
Allylic Etherification of SilanolsReductive etherification
Silicon-involved Reactions
Reductive DecarbonylationHydrogenation/isomerization
Lithiation/Silylation/Condensation
Organocatalytic multicomponent reaction
Si-H/Si-C/Si-O Functional Group
Organosilicon Chemistry
Asymmetric Catalysis
Si-Ligand
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Si-N Unit-containing Polymers: Synthesis and Application
Liqing Aia,b, Yongming Luoa, Zongbo Zhanga, Yongming Lia, Caihong Xua,b*
aInstitute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China bUniversity of Chinese Academy of Sciences, Beijing, 100049, P. R. China
A series of new polymers containing Si-N bonds, including polysiloxazane, polysilazanes,
phenylene-silazane-acetylene polymers, and polyborosilazanes were synthesized. The cross-coupling
reactions between acetylene terminated silicon-containing monomers and diiodoarylenes produced
silarylene-siloxane-acetylene polymers and phenylene-silazane-acetylene polymers. Various
polysilazanes were prepared by coammonolysis reaction of chlorosilane derivatives or their mixtures.
The application of the new silicon-containing polymers in the fields of adhesive, coating, and porous
materials were investigated.
References
1. Liu Wei; Luo Yongming; Xu Caihong, High Perform. Polym., 2013, 25, 543-550.
2. Lin Xiankai; Zhang Zongbo; Chen Limin; Zeng Fan; Luo Yongming; Xu Caihong, J. Organometa. Chem. 2014, 749, 251-
254
3. Zhang Zongbo; Wang Dan; Xiao Fengyan; Liang Qianying; Luo Yongming; Xu Caihong, RSC Adv., 2018, 8, 16746-
16752
4. Guo Xiang; Wang Dan; Guo Zhen; Zhang Zongbo; Cui Mengzhong; Xu Caihong, Surface& Coatings Tech., 2018,
350,101-109
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Catalytic Construction of Silacarbocycles Using Borylsilanes as
Synthetic Equivalents of Silylene
Toshimichi Ohmura*
Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto
University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
Recently silicon-containing organic groups have received increasing attention as new bioisosteres in
the drug discovery field.1 A particular interest in the screening of silicon-based bioisosteres is silicon-
containing cyclic skeletons. However, the skeletons that can be constructed by conventional synthetic
methods have been limited to date. Development of efficient methods to construct new silicon-
containing cyclic skeletons is highly attractive and could accelerate the developmet of silicon-
containing drugs.
We have reported that borylsilanes bearing a dialkylamino group on the silicon atoms react as
synthetic equivalents of silylene (:SiR2) in the presence of a palladium catalyst. Based on this process,
we established alkyne-alkyne-silylene [2+2+1] cycloaddition to afford 1-silacyclopenta-2,4-dienes2 and
1,3-diene-silylene [4+1] cycloaddition to give 1-silacyclopent-3-enes.3 Here, we describe new catalyst
system using borylsilanes bearing an alkoxy group on the silicon atoms. We found that 1,6-enynes 1
underwent alkene-alkyne-silylene [2+2+1] cycloaddition in the presence of rhodium catalyst, affording
1-silacyclopent-2-enes 2.4 It was suggested that formation of rhodium silylenoid is a key for proceeding
of the catalytic cycle. We applied the rhodium silylenoid-based catalytic system to construction of
seven-membered silacarbocycles. Thus, the rhodium-catalyzed reaction of deca-1,3-dien-8-ynes 3 with
borylsilane afforded 1-silacyclohepta-2,5-dienes 4 through [4+2+1] cycloaddition.
Scheme 1. Catalytic Construction of Silacarbocycles Using Borylsilanes as Synthetic Equivalents of Silylene
References
1. (a) Franz, A. K.; Wilson, S. O. J. Med. Chem. 2013, 56, 388–405. (b) Ramesh, R.; Reddy, D. S. J. Med. Chem. 2018, 61,
3779–3798.
2. Ohmura, T.; Masuda, K.; Suginome, M. J. Am. Chem. Soc. 2008, 130, 1526–1527.
3. Ohmura, T.; Masuda, K.; Takase, I.; Suginome, M. J. Am. Chem. Soc. 2009, 131, 16624–16625.
4. Ohmura, T.; Sasaki, I.; Suginome, M. Org. Lett. 2019, 21, 1649–1653.
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Fluorescent Silica Nanocages
Vuthichai Ervithayasuporn
Department of Chemistry, Center for Inorganic and Materials Chemistry, and Center of Excellence for
Innovation in Chemistry, Faculty of Science, Mahidol University, Rama VI Rd, Bangkok 10400, Thailand
Silica is one of the most naturally abundant compounds on the Earth. It is used in building materials,
electronic devices, in environmental remediation, and in chemical industry. Silica gel is a commonly
used laboratory sorbent for chromatographic separations, the binding properties of which can be tailored
through surface functionalization. For example, amine groups appended to the silica surface allow for
chemical adsorption of CO2, which generates a chelating group allowing sequestration of metal ions.
Interestingly, the mode of adsorption for organic molecules by silica is still controversial. While a
mechanism has been postulated and the outstanding capacity and absorptivity properties of silica are
well-known, very few studies have been devoted to determine the actual role of silica in the adsorption
of organic species. This may relate to the poor solubility of these sorbents in water or organic solvents,
hindering investigations using solution phase techniques (fluorescent emission, UV-vis absorption or
nuclear magnetic resonance). Meanwhile, polyhedral oligomeric silsesquioxane or silsesquioxane cages
can be considered as representative molecules for silica due to their closely related empirical formulae
(RSiO1.5). These systems consist of a rigid cage-like silica framework with organic groups attached to
the periphery, where it is possible to choose the desired size (from 0.5 nm). Herein, octasilsesquioxane
nanocubes or the smallest silica cages functionalized with organic fluorescent dye were presented, while
their anion recognition ability was probed through monitoring of fluorescence emission and UV-vis
absorption changes.1,2
References
1. Chanmungkalakul, S.; Ervithayasuporn, V. et al., Chem. Commun. 2017, 53, 12108.
2. Chanmungkalakul, S.; Ervithayasuporn, V. et al., Chem. Sci. 2018, 9, 7753.
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Direct Amidation of Carboxylic Acids Using Alkoxysilanes
Paul D. Lickiss,a* D. Christopher Braddock,a Ben C. Rowley,a David Pugh,a Teresa Purnomo,a Gajan Santhakumara and Steven J. Fussell,b
a Chemistry Department, Imperial College London, Molecular Sciences Research Hub, White City Campus,
Wood Lane, W12 0BZ, UK b Pfizer Limited, Ramsgate Road, Sandwich, Kent, CT13 9NJ, UK
The amide group is present in about 25% of all pharmaceuticals on the market and the need for a
convenient and inexpensive synthesis of amides was highlighted as the top priority by the ACS GCI
Pharmaceutical Roundtable in 2007.1 Since that time, the need for green, non-toxic, cost effective
organic functional group transformations, including direct amide bond formation, has become of
increasing interest to the chemical industry. The desire for inexpensive and convenient amidation
reagents together with some literature precedent for the use of silicas2 for amide formation prompted us
initially to investigate molecular silanols such as Ph3SiOH as direct amidation catalysts. We found that
several molecular silanols do indeed act as amidation catalysts, but the yields are low and catalyst
condensation reactions to give siloxanes can be a problem. More recently we turned our attention to
tetraalkoxysilanes (see Scheme 1, R = Me or Et) and find that (MeO)4Si is a particularly effective direct
amidation reagent.
Scheme 1. Use of alkoxysilanes to effect direct amidation
We have found3 that both (MeO)4Si and (EtO)4Si may be used as reagents to effect direct amidation
with (MeO)4Si being the more effective reagent.4 Thus, (MeO)4Si is a convenient and high yielding
reagent for direct amidation of a range of aliphatic and aromatic carboxylic acids with primary, cyclic
and acyclic secondary aromatic amines, and anilines. The method can even be applied successfully to
the direct amidation of an aromatic carboxylic acid with an aniline, a particularly difficult
transformation. The amide products can be isolated easily and in high yield without the need for
chromatographic purification as excess alkoxysilane can be removed by hydrolysis, and any remaining
amine or carboxylic acid is removed by an acid or base wash. The simple work-up procedure leads to
very low Process Mass Intensities compared to more conventional synthetic routes. In addition, we have
scaled up the method to one mole scale to give amides in near quantitative yield.
References
1. Constable, D. J. C.; Dunn, P. J.; Hayler, J. D.; Humphrey, G. R; Leazer Jr., J. L.; Linderman, R. J.; Lorentz, K.; Manley,
B. A.; Wells A.; Zaks, A.; Zhang, T. Y.; Green Chemistry 2007 9, 411-420.
2. For a recent example see, Zakharova, M. V.; Kleitz, F.; Fontaine, F.-G.; Dalton Trans., 2017 46, 3864-3876.
3. Braddock, D. C.; Lickiss, P. D.; Rowley, B. C.; Pugh, D.; Purnomo, T.; Santhakumar, G.; Fussell, S. J.; Organic Letters,
2018, 20, 950-953.
4. Previous work by Mukaiyama on less accessible reagents such as tetrakis(pyridine-2-yloxy)silane and tetrakis(1,1,1,3,3,3-
hexafluoro-2-propoxy)silane has also shown that (RO)4Si work well for direct amidation, see for example, Tozawa, T.;
Yamane, Y.; Mukaiyama, T.; Chem. Lett, 2005, 34, 1586-1587.
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INVITED LECTURE ǀ Page 41
Heavy Cyclobutadienes
Tsukasa Matsuo
Department of Applied Chemistry, Faculty of Science and Engineering,
Kindai University, 3-4-1, Kowakae, Higashi-Osaka, Osaka 577-8502, JAPAN
We have studied a variety of low-coordinate compounds of heavier group 14 elements by using the
bulky Rind (1,1,3,3,5,5,7,7-octa-R-substituted s-hydrindacen-4-yl) groups.1,2 Previously, we reported
the synthesis of the cyclobutadiene (CBD) silicon analogue, tetrasilacyclobutadiene, Si4(EMind)4 (1a),
bearing the bulky EMind groups (EMind = 1,1,7,7-tetraethyl-3,3,5,5-tetramethyl-s-hydrindacen-4-yl).3
The Si4 ring shows a planar rhombic charge-separated structure originating from the polar Jahn-Teller
(J-T) distortion to counteract the antiaromaticity with a cyclic 4π-electron system. This result is in sharp
contrast to the fact that the carbon CBDs are mostly stabilized by the covalent J-T distortion, thus
leading to the formation of a rectangular-shaped C4 ring with two isolated C=C bonds.
We now present the synthesis of some new heavy CBDs, Si4(Eind)4 (1b), Ge4(EMind)4 (2a),4 and
Ge4(Eind)4 (2b) (Eind = 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl), which can be obtained as room-
temperature stable crystalline compounds. We are now investigating the reactivity of the heavy CBDs.
Figure 1. Rind Groups and Heavy CBDs
References
1. T. Matsuo, N. Hayakawa, Science and Technology of Advanced Materials (STAM) 2018, 19, 108–129.
2. T. Matsuo, K. Tamao, Bull. Chem. Soc. Jpn. 2015, 88, 1201–1220 (Inside Cover).
3. K. Suzuki, T. Matsuo, D. Hashizume, H. Fueno, K. Tanaka, K. Tamao, Science 2011, 331, 1306–1309.
4. K. Suzuki, Y. Numata, N. Fujita, N. Hayakawa, T. Tanikawa, D. Hashizume, K. Tamao, H. Fueno, K. Tanaka, T. Matsuo,
Chem. Commum. 2018, 54, 2200–2203 (Front Cover).
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Nanyang Technological University
INVITED LECTURE ǀ Page 42
Controlled Synthesis of Oligosiloxanes
Kazuhiro Matsumoto, Yasushi Satoh, Masayasu Igarashi, Kazuhiko Sato, Shigeru Shimada
National Institute of Advanced Industrial Science and Technology (AIST)
1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
Oligo- and polysiloxanes (silicones) are used as irreplaceable materials in a wide range of fields
owing to their excellent properties including high thermal stability, light stability and transparency, high
gas permeability, electrical insulation property, and constancy of properties over a wide temperature
range. For the further development of high performance siloxane materials, precise structural control of
oligo- and polysiloxanes is indispensable. However, synthetic methods for siloxane compounds are
surprisingly unexplored, and it is difficult to synthesize siloxane materials with well-defined structures
by the conventional methods, hydrolytic condensation reaction of chlorosilanes or alkoxysilanes and
base- or acid-catalyzed ring-opening polymerization of cyclic oligosiloxanes. Although some new
synthetic methods for siloxane compounds have recently been developed, accessible structures are still
very limited.
We have recently succeeded in developing several methods that achieve controlled syntheses of
oligosiloxanes.1 One is a highly efficient one-pot synthesis of sequence-controlled oligosiloxanes. By
repeating two reactions, 1) B(C6F5)3-catalyzed selective dehydrocarbonative coupling of a
dihydrosilane and an alkoxysilane and 2) B(C6F5)3-catalyzed hydrosilylation of a monohydrosiloxane
and a ketone (Scheme 1), various sequence-controlled oligosiloxanes (up to undecasiloxane) were
synthesized in high yields in one-pot manner. Other new procedures for controlled/selective synthesis
of oligosiloxanes are also presented.
Scheme 1. Example of one-pot iterative synthesis of sequence-controlled oligosiloxanes
This work was supported by the "Development of Innovative Catalytic Processes for Organosilicon
Functional Materials" project (PL: K. Sato) from the New Energy and Industrial Technology
Development Organization (NEDO).
References
1. Igarashi, M.; Kubo, K.; Matsumoto, T.; Sato, K.; Ando W.; Shimada, S. RSC Adv., 2014, 4, 19099-19102; Satoh, Y.;
Igarashi, M.; Sato, K.; Shimada, S. ACS Catal. 2017, 7, 1836-1840; Matsumoto, K.; Sajna, K. V.; Satoh, Y.; Sato, K.;
Shimada, S. Angew. Chem. Int. Ed. 2017, 56, 3168-3171. Igarashi, M.; Matsumoto, T.; Yagihashi, F.; Yamashita, H.;
Ohhara, T.; Hanashima, T.; Nakao, A.; Moyoshi, T.; Sato, K.; Shimada, S. Nat. Commun. 2017, 8, 140. Matsumoto, K.;
Ohba, Y.; Nakajima. Y.; Shimada, S.; Sato, K. Angew. Chem. Int. Ed. 2018, 57, 4637-4641; Matsumoto, K.; Shimada, S.;
Sato, K. Chem. Eur. J. 2019, 25, 920-928.
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The 7th Asian Silicon Symposium
INVITED LECTURE ǀ Page 43
The curious case of silylene in transition metal chemistry
Shabana Khan
Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune,
Dr. Homi Bhaba Road, Pune-411008, India
The interaction of transition metals, especially the coinage metals (Cu, Ag, Au) with arenes is of high
importance as they serve as the key intermediates in various catalytic reactions e.g. cycloaddition, cross
coupling, cycloisomerization, C-H functionalization and also display multifarious coordination
chemistry. However, the isolation of these complexes is a challenging task due to weaker interactions
between them. We have explored the utility of silylene, [PhC(NtBu)2SiN(SiMe3)2], as a ligand to
prepare the Cu(I) and Au(I)-arene cationic complexes.1 An appealing facet of [PhC(NtBu)2SiN(SiMe3)2]
is that it accepts electron density from the metal as evidenced in its coinage metal complexes.2 This
potential has been duly realized through the isolation and characterization of an unprecedented [Cu(η6-
C6H6)]+ and [Au(η1-C6H6)]+ complexes.3,4 For a direct systematic comparison, we have carried out the
same reactions with N-heterocyclic carbene which reveals, unlike silylene, there is no M→CNHC back-
bonding. These complexes are further used for their reactivity study and catalytic application.
Chart 1. Selected Si(II) supported Cu(I) and Au(I)-arene complexes.
References
1. (a) S. Khan, S. K. Ahirwar, S. Pal, N. Parvin, N. Kathewad, Organometallics, 2015 , 34, 5401–5406. (b) S. Khan, S. Pal,
N. Kathewad, P. Parameswaran, S. De, I. Purushothaman, Chem. Commun., 2016, 52, 3880–3882. (c) N. Parvin,
R.Dasgupta, S. Pal, S. S. Sen, S. Khan, Dalton Trans., 2017, 46, 6528-6532.
2. N. Parvin, S. Pal, S. Khan, S. Das, S. K. Pati, H. W. Roesky, Inorg. Chem., 2017, 56, 1706–1712.
3. N. Parvin, S. Pal, J. Echeverría, S. Alvarez, S. Khan, Chem. Sci., 2018, 9, 4333-4337.
4. N. Parvin, S. Khan (unpublished result).
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Nanyang Technological University
INVITED LECTURE ǀ Page 44
Exhaustively Trichlorosilylated Tetrelides: Synthesis and
Reactivity
Matthias Wagner,a,* Chantal Kunkel,a Isabelle Georg,a Julian Teichmanna
aGoethe-Universität Frankfurt, Campus Riedberg, 60438 Frankfurt/Main, Germany
Treatment of Si2Cl6 with [R4N]Cl in CH2Cl2 generates the transient silanide intermediate [SiCl3]‒,
which can react further with Si2Cl6 to furnish linear, cyclic, or cage-type oligosilanes (“silafulleranes”).1
If [SiCl3]‒ is liberated in the presence of CCl4 or GeCl4, the methanide 1C2 or germanide 1Ge3 is
formed in essentially quantitative yields. The corresponding silanide 1Si1,4 is best prepared from
Si(SiCl3)4 through chloride-induced heterolytic cleavage of one of its Si‒Si bonds.1,3 1Si has been
advertised as weakly coordinating anion.4 Herein we disclose series of adducts 2C-2Ge of various
Lewis acids (LA) with 1C-1Ge.3 A special case is the Lewis acid AlCl3, which abstracts a chloride ion
from 1C (likely) to generate an intermediate silene, which can subsequently add various
organochlorides to afford corresponding organosilanes 3.5 AlCl3 also induces the skeletal rearrangement
of 1Ge to give the mixed oligo(germane-silane) 4.3
While 1C (and its higher carbon homologues, which we have also prepared) is a versatile building
block for functionalized silicone precursors,2 compounds of type 2 and 4 are relevant for the
semiconductor industry.3
Figure 1. Tris(trichlorosilyl)tetrelides 1 and some of their reaction products 2-4; LA = Lewis acid.
References
1. Review: Teichmann, J.; Wagner, M. Chem. Commun. 2018, 54, 1397-1412.
2. Georg, I.; Teichmann, J.; Bursch, M.; Tillmann, J.; Endeward, B.; Bolte, M.; Lerner, H.-W.; Grimme, S.; Wagner, M. J.
Am. Chem. Soc. 2018, 140, 9696-9708.
3. Teichmann, J.; Kunkel, C.; Georg, I.; Moxter, M.; Santowski, T.; Bolte, M.; Lerner, H.-W.; Bade, S.; Wagner, M. Chem.
Eur. J. 2019, 25, 2740-2744.
4. Olaru, M.; Hesse, M. F.; Rychagova, E.; Ketkov, S.; Mebs, S.; Beckmann, J. Angew. Chem. Int. Ed. 2017, 56, 16490-
16494.
5. Kunkel, C.; Teichmann, J.; Lerner, H.-W.; Wagner, M. DE 102019104543.6 (priority date: 22. 02. 2019).
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INVITED LECTURE ǀ Page 45
Low-coordinate Silicon Chemistry Enabled by Anionic N-
Heterocyclic Olefins
Eric Rivard,a,* Matthew M. D. Roy,a Samuel R. Baird,a Alvaro Omana,a Linkun Miao,a Yuqiao Zhou,a Michael J. Fergusona
aDepartment of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton, Alberta, CANADA
In this presentation, a series of sterically hindered N-heterocyclic olefin (NHO) ligands and their
anionic counterparts will be discussed.1 Focus will be given to the preparation of a stable acyclic, two-
coordinate vinyl- and divinylsilylenes featuring anionic NHO ligands,2 and their ability to activate small
molecules. Time permitting, the bulkiest NHC to date will be described,3 as well as the use of
intramolecular Frustrated Lewis Pair ligands to coordinate reactive main group hydrides (EH2; E =
group 14 element).
References
1. For review articles, see: a) Rivard, E. Chem. Soc. Rev. 2016, 45, 989-1003. b) Roy, M. M. D.; Rivard, E. Acc. Chem. Res.
2017, 50, 2017-2025.
2. Hering-Junghans, C.; Andreiuk, P.; Ferguson, M. J.; McDonald, R.; Rivard, E. Angew. Chem. Int. Ed. 2017, 56, 6272-
6275.
3. Roy, M. M. D.; Ferguson, M. J.; McDonald, R.; Rivard, E. Chem. Commun. 2018, 54, 483-486.
IL – 25
Nanyang Technological University
SHORT ORAL PRESENTATION ǀ Page 46
Reactions of a W-Si Triple Bonded Complex with Aldehydes:
Metathesis-Like Fragmentation of the Four-Membered Products
Hisako Hashimoto,a,* Takashi Yoshimoto,a Nozomi Takagi,b Shigeyoshi Sakaki,b,c
Naoki Hayakawa,d Tsukasa Matsuo,d Hiromi Tobitaa,*
aDepartment of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan bElements Strategy Initiative for Catalysts and Batteries, Kyoto University, Nishikyo-ku, Kyoto 615-8245, Japan
cFukui Institute for Fundamental Chemistry, Kyoto University, Sakyo-ku, Kyoto 606-8103, Japan dFaculty of Science and Engineering, Kindai University, Kowakae, Higashi-Osaka, 577-8502, Japan
Metathesis of unsaturated organic compounds catalyzed by transition metal complexes having a
metal-carbon multiple bond, i.e. carbene and carbyne complexes, is one of the most important chemical
transformation reactions and widely applied to organic syntheses.1 On the contrary, metathesis reactions
mediated by the heavier Group 14 analogues have never been reported.2 In the metathesis reactions, it
is proposed that four-membered metallacycles are key intermediates and their formation via [2+2]
cycloaddition and subsequent fragmentation of them into two unsaturated organic species via retro-
[2+2] cycloaddition are both essential processes.
Our group recently succeeded in synthesizing silylyne complexes of tungsten by developing a
new synthetic strategy.3,4 The one bearing a bulky aryl group (Eind) on silicon, 1, which takes a dimeric
from in the solid state but is in rapid dissociation equilibrium with its monomer in solution, reacted with
several unsaturated organic compounds via [2+2] cycloaddition.4 When aldehydes were employed as
substrates, four-membered metallacycles 2 were formed through formation of [2+2] cycloaddition
intermediates A followed by addition of the second aldehyde to A. Upon heating, the metallacycles 2
underwent metathesis-like fragmentation into W≡C and Si=O species, the latter of which was isolated
as a dimeric form, 1,3-cyclodisiloxane B (Scheme 1).5 This is the first metathesis-like fragmentation of
silametallacycles. Here we will present these reactions with aldehydes as well as detailed theoretical
calculations on the reaction mechanism.
Scheme 1. Reactions of silylyne complex 1 with aldehydes.
References
1. a) Chauvin, Y. Angew. Chem. Int. Ed. 2006, 45, 3741-3747; b) Schrock, R. R. Angew. Chem. Int. Ed. 2006, 45, 3748-
3759; c) Grubbs, R. H. Angew. Chem. Int. Ed. 2006, 45, 3760-3765; d) Fürstner, A. Angew. Chem. Int. Ed. 2013, 52, 2794-
2819; e) Engel, P. F.; Pfeffer, M. Chem. Rev. 1995, 95, 2281-2309.
2. Hashimoto, H.; Tobita, H. Coord. Chem. Rev. 2018, 355, 362-379.
3. Fukuda, T.; Yoshimoto, T.; Hashimoto, H.; Tobita, H. Organometallics 2016, 35, 921-924.
4. Yoshimoto, T.; Hashimoto, H.; Hayakawa, N.; Matsuo, T.; Tobita, H. Organometallics 2016, 35, 3444-3447.
5. Yoshimoto, T.; Hashimoto, H.; Takagi, N.; Sakaki, S.; Hayakawa, N.; Matsuo, T.; Tobita, H. Chem. Eur. J. 2019, 25,
3795-3798.
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SHORT ORAL PRESENTATION ǀ Page 47
Synthesis of Hexahydrosilaphenalene by Two Different methods:
Trianion Route and Triple Metathesis Route
Kenkichi Sakamoto,* Takumi Sugino, Shohei Oka, Junghun Lee, Ayaka Furusawa, Shunya Nagata, Satoshi Ozaki, Haruka Takagi
Department of Chemistry, Faculty of Science, Shizuoka University
836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
Phenalenyl is an odd alternant
hydrocarbon having a non-bonding
orbital and its derivatives are investigated
from various points of view. However,
only a few compounds of heteroatom
substituted phenalenyls and phenalenes
are known so far. We wish to report
herein two different synthetic methods of
hexahydrosilaphenalene 1 as a candidate of silaphenalene’s precursor. The compound consists of a
bowl shaped tricyclic moiety and a stem made of Si-R bond; thus we call it “cocktail glass compound”.
Because the bowl inversion does not occur unless the Si-R bond cleavage takes place, the compounds
are obtained as a racemic mixture of C3-symmmetic enantiomers.
(1) Trianion route. Recently, we have found that trilithiocyclododecatriene 3 is obtained by the
reaction of tribromide 2 with tert-BuLi quantitatively. Compound 3 is stable for several hours at rt in
THF and allowed to react with trichlorosilanes to give 1 in low to moderate yields (R = H, Me, Ph, 4-
Ph-C6H4, and Mes) as shown in eq. 1.
(2) Triple Metathesis Route. A short-cut synthesis of 1 is achieved by intramolecular triple
metathesis of tri(1-cyclobutenyl)silane 4 using Grubbs' catalysts as shown in eq. 2. Although the
Grubbs metathesis of alkenylsilanes sometimes give poor results due to the steric hindrance, the
isomerization of 4 in the presence of second-generation Grubbs' catalyst proceeds to give 1 in moderate
yield (R = Me, Ph, and 2-Me-C6H4). Releasing of the high ring strain energy of cyclobutenyl moieties
should be a driving force of the isomerization; the estimated stabilization energy from 4 to 1 is 72.9
kcal/mol (R = Me) by DFT calculations at the M06, 6-31G* level.
(1)
(2)
OP – 02
Nanyang Technological University
SHORT ORAL PRESENTATION ǀ Page 48
Highly Compression-Tolerant and Durably Hydrophobic
Macroporous Silicone Sponges Synthesized by One-Pot Click
Reaction for Rapid Oil/Water Separation
Jinfeng Cao, Shengyu Feng*
Key Laboratory of Special Functional Aggregated Materials & Key Laboratory of Colloid and Interface
Chemistry (Shandong University), Ministry of Education; School of Chemistry and Chemical Engineering,
Shandong University, Jinan 250100, P. R. China
We first report a novel and simple method for the synthesis of macroporous silicone sponges via one-
pot thiol-ene click reaction at -10oC.1,2 The successful synthesis was confirmed by scanning electron
microscopy, fourier transform infrared spectroscopy and elemental analysis. The sponge has high
porosity, low density, durably and high hydrophobicity, super-oleophilicity, good thermal insulation,
and excellent compressibility (11.01 MPa at 93% strain, superior to all the previously reported silicone
sponges) in addition to conventional advantages of silicone such as non-flammability, excellent stability,
and non-toxicity. The morphology, pore size, density, and compression properties of the sponge are also
controllable by adjusting the synthesis conditions. Furthermore, the sponge could be used for rapid
oil/water separation with good absorption ability, excellent reusability and separation efficiency
(>99%).3, 4
Scheme 1. Schematic illustration of the preparation of the silicone sponge.
References
1. Cao J, Wang D, An P, Zhang J, and Feng S. Journal of Materials Chemistry A 2018;6(37):18025-18030.
2. Cao J, Zuo Y, Lu H, Yang Y, Feng S, Journal of Photochemistry and Photobiology A: Chemistry, 2018; 350: 152-163.
3. Lowe AB. Polym. Chem 2014(5):4820-4870.
4. Feng S, Zhang J, Li M, and Zhu Q. Organosilicon polymers and application. Beijing: Chemical Industry Press, 2010, 1-
20.
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The 7th Asian Silicon Symposium
SHORT ORAL PRESENTATION ǀ Page 49
Hydroboration of Nitriles Catalyzed by a Ruthenium-Bis(silyl)
Chelate Complex and Subsequent Deborylative N-Arylation
Takeo Kitano, Takashi Komuro, Hiromi Tobita*
Department of Chemistry, Graduate School of Science, Tohoku University,
6-3, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578, JAPAN
Selective conversion of nitriles to organic imines and amines under mild conditions is a useful
chemical transformation in organic synthesis. One possible route for this conversion is hydroboration
of nitriles and subsequent deborylative N-arylation of the resulting N-borylated products. In the last
several years, catalytic hydroboration of nitriles has been investigated by several groups, which mostly
resulted in double hydroboration of C–N triple bonds to give N,N-bis(boryl)amines. However, catalysts
that are active for both double and single hydroboration reactions have not been reported.
We have previously demonstrated that 16-electron ruthenium complexes Ru[3(Si,O,Si)-
xantsil](PR3)(CO) (1, R = alkyl, amino) with a bis(silyl) chelate ligand xantsil [(9,9-dimethylxanthene-
4,5-diyl)bis(dimethylsilyl)] catalyze the reactions of arylalkynes with hydrosilanes to give unusual
products via silylation of the aryl group1 or double silylation of the aryl group and the C–C triple bond.2
These findings prompted us to investigate hydroboration of nitriles catalyzed by complexes 1, and we
found that complex 1a [R = cyclopentyl (Cyp)] became an active catalyst for both double and single
hydroboration reactions of nitriles using pinacolborane (HBpin) for the former reaction and 9-
borabicyclo[3.3.1]nonane (9-BBN) for the latter reaction under mild conditions.3 Furthermore, we
applied Buchwald’s method for conversion of arylbromides to arylamines4 to deborylative N-arylation
of the hydroboration products, i.e. bis(boryl)amines 2 and N-borylimines 3, and succeeded in opening
novel one-pot synthetic routes from nitriles to N,N-diarylamines 4 and N-arylaldimines 5.3
Possible mechanisms for the double and single hydroboration reactions will also be discussed.
References
1. Komuro, T.; Kitano, T.; Yamahira, N.; Ohta, K.; Okawara, S.; Mager, N.; Okazaki, M.; Tobita, H. Organometallics 2016,
35, 1209-1217.
2. Kitano, T.; Komuro, T.; Ono, R.; Tobita, H. Organometallics 2017, 36, 2710-2713.
3. Kitano, T.; Komuro, T.; Tobita, H. Organometallics 2019, 38, 1417-1420.
4. Guram, A. S.; Rennels, R. A.; Buchwald, S. L. Angew. Chem. Int. Ed. Engl. 1995, 34, 1348-1350.
OP – 04
Nanyang Technological University
SHORT ORAL PRESENTATION ǀ Page 50
Flame-retardant Polymer Foam Composites Via Coating Silicone Resin
Lianbin Wu*, Qian Wu, Jin Cheng, Yongbing Pei
Key Laboratory of Organosilicon and Materials Technology Ministry of Education, Hangzhou Normal
University, Hangzhou, 311121, P. R. China
In this study, highly flame retardant polymer foam composites were fabricated via coating silicone
resin (SiR) polymer through the dip-coating method. After coating SiR on polymer foam surface, the
mechanical property and thermal stability of SiR-coated polymer foam (PSiR) composites were greatly
enhanced.The minimum oxygen concentration to support the combustion of foam materials is greatly
increased, i.e. from LOI 14.6% for pure foam to LOI 26-29% for the PSiR composites studied.
Especially, adjusting pendant group to Si-O-Si group ratio (R/Si ratio) of SiRs produces highly flame
retardant PSiR composites with low smoke toxicity. Cone calorimetry results demonstrate that 44-68%
reduction in the peak heat release rate for the PSiR composites containing different R/Si ratios over
pure foam is achieved by the presence of appropriate SiR coating. Digital and SEM images of post-burn
chars indicate that the SiR polymer coating can be transformed into silica self-extinguishing porous
layer as effective inorganic barrier effect. This research provided a universal method to produce flame
retardant polymer foam composites with enhanced mechanical and thermal properties.
Figure 1. (a) Formation of silica self-extinguishing layer
transferred from Silicone resin coating during the combustion
process; (b) FTIR spectra and (c) EDS results of PSiR
composites after combustion
Figure 2. Combustion process of (upper) pure PU
foam and (lower) PSiR composite recorded at different
time.
References
1. Q. Wu, Q. Zhang, L. Zhao, S.N. Li, L.B. Wu, J.X. Jiang, L.C. Tang, Journal of Hazardous Materials 2017,336, 222-231.
2. Q. Wu, L.-X. Gong, Y. Li, C.-F. Cao, L.-C. Tang, L. Wu, L. Zhao, G.-D. Zhang, S.-N. Li, J. Gao, Y. Li, Y.-W. Mai, ACS
nano 2018, 12, 416-424.
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The 7th Asian Silicon Symposium
SHORT ORAL PRESENTATION ǀ Page 51
Aerobic [M]-/Organo-Catalyzed Oxidation of Siloxanes – Perspective Way to the Functionalized Siloxanes
Irina K. Goncharova, Ashot V. Arzumanyan, Aziz M. Muzafarov
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilova Street,
Moscow 119991, Russian Federation
Synthesis of organosilicon products with a “polar” functional group within organic substituents is
one of the most fundamentally and practically important challenges in today’s chemistry of silicones.
Incorporation of a “polar” function into organosilicon compounds opens quite unique opportunities for
their subsequent modification and preparation of new copolymers, MOFs, HOFs and other hybrid
materials. In addition, modification by incorporation of functional groups would also allow other
problems to be solved, namely, the low mechanical strength and “incompatibility” of silicones with
organic polymers.
To solve these problems obtaining of functionalized (–OH, –C6H4C(O)OH) siloxanes via the aerobic
oxidation of hydride or p-tolyl-siloxanes was suggested (Scheme 1). This approach is based on “green”,
commercially available, simple, and inexpensive reagents and employs mild reaction conditions:
Cu(OAc)2 or Co(OAc)2 / NHPI or NHSI – catalytic system, O2 as the oxidant, process temperature from
30 to 60 °C, atmospheric pressure.
Scheme 1
It was shown that it is principally possible to perform the gram-scale aerobic [M]-/organo-catalyzed
oxidation of a Si−H group to a Si−OH group with retention of the organosiloxane core. This method
allows various monomeric, oligomeric and polymeric siloxanols of linear, branched and cyclic structure
to be synthesized.1
This approach was later extended to p-carboxyphenyl-siloxanes synthesis.2 The reaction is general
and allows to synthesize both mono- and di-, tri-, and poly(p-carboxyphenyl)siloxanes. Furthermore, it
was shown that the suggested method is applicable for the oxidation of organic alkylarene derivatives
(Ar−CH3, Ar−CH2−R) to the corresponding acids and ketones0 (Ar−C(O)OH and Ar−C(O)−R).
All the organosilicon products were obtained and isolated in gram amounts (up to 5 g) and
characterized using complex of physico-chemical methods (1D- and 2D-NMR, IR, ESI-HRMS, GPC,
X-ray). Molecular structure of bis(trimethylsiloxy)methylsilanol that is liquid at room temperature was
confirmed using in situ crystallization. X-ray data also confirmed that para-carboxyphenylsiloxanes in
crystalline state tend to form hydrogen-bonded polymers (HOF-like structures).
References
1. Arzumanyan, A. V.*; Goncharova, I. K.; Novikov, R. A.; Milenin, S. A.; Boldyrev, K. L.; Solyev, P. N.; Volodin, A.D.,
Smol’yakov, A. F.; Korlyukov, A. A.; Muzafarov, A. M.* Green Chem. 2018, 20 (7), 1467−1471.
2. Goncharova, I. K.; Silaeva, K.P.; Arzumanyan, A.V.*; Anisimov, A.A.; Milenin, S.A.; Novikov, R.A.; Solyev, P.N.;
Tkachev, Ya.V.; Volodin, A.D.; Korlyukov, A.A.; Muzafarov A.M. J. Am. Chem. Soc. 2019, 141, 5, 2143-2151
This work was supported by the Grant of the Government of the Russian Federation No. 14.W03.31.0018.
OP – 06
Nanyang Technological University
SHORT ORAL PRESENTATION ǀ Page 52
Fluorescent Polysiloxane-based Materials for Bioimaging
Yujing Zuo,a and Shengyu Fengb,*
a Institute of Fluorescent Probes for Biological Imaging, School of Chemistry and Chemical Engineering,
School of Materials Science and Engineering, University of Jinan, Jinan 250100, P. R. China b Key Laboratory of Special Functional Aggregated Materials (Shandong University), Ministry of Education;
School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, P. R. China
Fluorescent materials have been applied in luminescent imaging techniques due to its unique
advantages, including low photodamage to the samples, weak background fluorescence, and high
spatial resolution. To the best of our knowledge, polysiloxane-based fluorescent materials applied in
bioimaging have not been well discussed to date. This lecture intends to introduce a series of
polysiloxane-based materials with superior fluorescent property. The lecture involves three parts: 1).
Two photon luminescence of elastomers was detected. More interestingly, the fluorescence intensity of
elastomers exhibited thermally responsive properties, which could be observed by the naked eye.1 2).
Polysiloxane has been found as a powerful tool for detecting the ClO-/GSH cycle in situ both in lived
cells and in zebrafishs. 3). We presented a facile, and cost-less Stöber method to fabricate robust silica
nanoparticles (SiO2 UCNPs), which could discriminate live and apoptosis cells by taking advantage of
the unique surface property of SiO2 UCNPs for the first time. These works demonstrated that the
potential of polysiloxane based fluorescent probes for versatile in vivo or in vitro applications in future.
Scheme 1. Illustration of the thermal responsive process and the application of the elastomers
References
1. Yujing Zuo, et al., Chemical Science, 2018, 9, 2774–2781.
2. Yujing Zuo, et. al., Anal. Chem., 2019, 91, 1719−1723.
3. Yujing Zuo, et. al., Anal. Chem., 2018, 90, 14602−14609.
4. Yujing Zuo, et. al., Sensor and Actuator B, 2019, 291, 235-242.
OP – 07
The 7th Asian Silicon Symposium
SHORT ORAL PRESENTATION ǀ Page 53
Trinuclear Pt Complexes with Si-ligands and their Catalysis
Kohtaro Osakada
Laboratory for Chemistry and Life Science, Tokyo Institute of Technology.
4259 Nagatsuta, Yokohama 226-8503, Japan.
Hydrosilylation of carbonyl compounds using Pt catalysis is much less common than the reaction
using other transition metals such as Fe, Ni, Cu, and Rh. Triplatinum(0) complexes with bridging
diarylsilylene ligands, formulated as [{Pt(PMe3)}3(μ-SiPh2)3] catalyzes hydrosilyation of benzaldehyde
with H2SiPh2 to produce diphenyl(benzyloxy)silane along with concurrent hydrosilyation and
dehydrosilyation of phenyl(methyl)ketone (eq 1).1 Dehydrogenative coupling of H2SiPh2 and phenol
is also catalyzed to yield
diphenyl(4-methylphenoxy)silane.
Kinetic studies of the reactions
using various aromatic aldehydes
and using deuterated labelled
diphenylsilane suggested that the
catalyst keeps the triangular
trinuclear structure throughout the
reaction and that the reaction
mechanism is totally different from
those catalyzed by Pt(PPh3)3.2
The reaction involves addition of H2SiPh2 to the Pt3Si3
complex to produce a Pt3Si4 complex, [{Pt(PMe3)}3(H)2(-
SiPh2)4] and further insertion of carbonyl group into the Pt-
Si bond. The intermediate formed by addition of H2SiPh2
was isolated and characterized by X-ray crystallography
(Figure 1) and NMR spectroscopy. Thermodynamic
parameters of the process are determined to be G° = –8.0
kJ mol-1, H° = –51.7 kJ mol-1, and S° = –146 J mol-1K-1.
The stoichiometric and catalytic reactions using
[{Pt(PMe3)}3(-SiPh2)3]3 will be also mentioned.
Figure 1 Structure of [{Pt(PMe3)}3(H)2(-SiPh2)4]
References
1. Tanabe, M.; Kamono, M.; Tanaka, K. Osakada, K. Organometallics 2017, 36, 1929-1935.
2. Tsuchido, Y.; Kamono, M.; Tanaka, K.; Osakada, K. Bull. Chem. Soc. Jpn. 2018, 91, 858-864.
3. Tanabe, M.; Tanaka, K.; Omine, S.; Osakada, K. Chem. Commun. 2014, 50, 6839-6842.
OP – 08
Nanyang Technological University
SHORT ORAL PRESENTATION ǀ Page 54
Hybrid of POSS-Based Porous Polymers with Polysiloxanes
Ruixue Sun,a,b Shengyu Feng,a,b Dengxu Wang,a,b* Hongzhi Liua,b
a National Engineering Research Center for Colloidal Materials, b Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, School of Chemistry and
Chemical Engineering, Shandong University, Jinan 250100, P. R. China
Porous organic polymers have been widely applied in gas storage, separation, catalysis, sensing, etc.
However, most of these materials cannot be processed due to their highly crosslinked and stiff networks,
thus limiting their application extension.1 Herein, we report a facile approach to realize their
processibility by the hybrid of them with polysiloxane, affording novel composite materials. One typical
example is physically blending them into a thiol-containing polysiloxane matrix (PMMS) followed by
an efficient thiol-ene crosslinking reaction, resulting in novel silicone elastomers (Figure 1).2 The
applied porous materials are polyhedral oligomeric silsesquioxane-based hybrid porous polymers
(HPPs), which were prepared by the Heck reactions of octavinylsilsesquioxane with 4,4’-
dibrombiphenyl and/or 1,3,6,8-tetrabromopyrene. They exhibit tunable fluorescence with a continuous
color change from blue to red by altering the molar ratio of biphenyl and pyrene units. This remarkable
fluorescence modulation endows the elastomers incorporated with HPP materials similar multicolor
emissions from blue to red depending on the added HPP. It was observed that HPP materials were well
dispersed in the polymeric matrix when the amount of HPPs was below 20 mg per gram of PMMS.
Furthermore, multicolored UV-LEDs based on these silicone elastomers were constructed by an in-situ
crosslinking method; the devices show color-transformable property by controlling the light switches
(Figure 1). These results reveal that blending insoluble porous materials with polymer matrix is an
effective strategy to realize their processibility and result in novel functional composites. This simple
strategy could be certainly expanded to other insoluble porous materials.
Figure 1. Hybrid of POSS-based fluorescent porous polymers with polysiloxane matrix for silicone elastomers and
multicolored UV-LEDs
References
1. Das, S.; Heasman, P.; Ben, T.; Qiu, S. L. Chem. Rev. 2017, 117, 1515-1563.
2. Sun, R.; Feng, S.; Wang, D.; Liu, H. Chem. Mater. 2018, 30, 6370-6376.
OP – 09
The 7th Asian Silicon Symposium
SHORT ORAL PRESENTATION ǀ Page 55
A Dimeric Cobaltosilylene Complex for Catalytic C-C Bond
Formation
Cheuk-Wai So*
a Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang
Technological University
Treatment of the amidinato silicon(I) dimer [PhC(NtBu)2Si:]2 (1) with CoBr2 in toluene for 10 days
afforded the dimeric amidinato cobaltosilylene [(LSi)μ-{CoBr(LSiBr)}]2 (2). It is capable of catalysing
C–H bond functionalization, whereby a combination of 2, phosphine and MeMgI can regio- and
stereoselectively promote the addition of the ortho-C-H bond in arylpyridines with the CC triple bonds
in alkynes. Other transition-metal and main-group element complexes supported by the amidinato
silicon(I) dimer will also presented
Scheme 1. The addition of the ortho-C-H bond in arylpyridines with the C-C triple bonds in alkynes
References
1. Khoo, S.; Cao, J.; Yang, M.-C.; Shan, Y.-L.; Su, M.-D.; So, C.-W. Chem. - Eur. J. 2018, 24, 14329-143.
OP – 10
Nanyang Technological University
POSTER PRESENTATION ǀ Page 56
Plenary Lecture
Keynote Lecture
Invited Lecture
Short Oral Presentation
Abstract
Poster Presentation
The 7th Asian Silicon Symposium
POSTER PRESENTATION ǀ Page 57
Platinum-Catalyzed Reactions of 3,4-Bis(dimethylsilyl)- and
2,3,4,5-Tetrakis(dimethylsilyl)thiophene with Alkynes and Alkenes
Akinobu Naka*, Takashi Mihara
Department of Life Science, Kurashiki University of Science and the Arts, Nishinoura, Tsurajima-cho,
Kurashiki, Okayama 712-8505, Japan
We have reported that the platinum-catalyzed reactions of 2,3-bis(diethylsilyl)thiophene with alkynes
such as diphenylacetylene, 3-hexyne, phenylacetylene, trimethylsilylacetylene, afforded the respective
[1,4]disilino[2,3-b]thiophenes.1 We also demonstrated that the reactions of 2,3-
bis(diisopropylsilyl)thiophene with alkynes having the bulky substituents, such as
trimethylsilylacetylene and mesitylacetylene gave the products arising from sp-hybridized C-H bond
activation of the alkynes.2 In this paper we report the platinum–catalyzed reactions of 3,4-
bis(dimethylsilyl)thiophene (1) and 2,3,4,5-tetrakis(dimethlsilyl)thiophene with mono- and di-
substituted alkynes, and with mono-substituted alkenes.
Treatment of compound 1 with diphenylacetylene in the presence of a catalytic amount of Pt(PPh3)4
in refluxing benzene for 2 h gave 1,1,4,4-tetramethyl-2,3-diphenyl-1,4-dihydro-[1,4]disilino[2,3-
c]thiophene (2) in quantitative yield (Scheme 1). Similar reactions of 1 with 3-hexyne and
phenyltrimethylsilylacetylene afforded 2,3-diethyl-1,1,4,4-tetramethyl-1,4-dihydro-[1,4]disilino[2,3-
c]thiophene (3) and 1,1,4,4-tetramethyl-2-phenyl-3-(trimethylsilyl)-1,4-dihydro[1,4]disilino[2,3-
c]thiophene (4) in 62% and 98% yields, respectively.
Scheme 1. Reactions of 1 with diphenylacetylene, 3-hexyne and phenyltrimethylsilylacetylene.
We also report the reaction of 1 with alkenes in the presence of a platinum catalyst in refluxing
benzene, and the reaction of 2,3,4,5-tetrakis(dimethylsilyl)thiophene (5) with diphenylacetylene and
styrene.
Scheme 2. Reactions of 5 with diphenylacetylene.
References 1. Naka, A.; Mihara, T.; Kobayashi, H.; Ishikawa, M. J. Organomet. Chem. 2016, 822, 221-227.
2. Naka, A.; Mihara, T.; Kobayashi, H.; Ishikawa, M. ACS omega 2017, 2, 8517-8525.
P – 01
Nanyang Technological University
POSTER PRESENTATION ǀ Page 58
Synthesis and Reactions of Hexahydrosilaphenalenes Using
Trilithiocyclododecatriene
Ayaka Furusawa, Haruka Takagi, Shohei Oka, Takumi Sugino, Kenkichi Sakamoto*
Department of Chemistry, Faculty of Science, Shizuoka University
836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
Recently, we have synthesized hexahydrosilaphenalenes 3a-e (R = H, Me, Ph, Mes, 4-PhC6H4) in
low to moderate yields by the reactions of the corresponding trichlorosilanes with 1,5,9-
trilithiocyclododeca-1,5,9-triene (2), prepared by triple-lithiation of tribromide 1 with 6 equiv of tert-
butyllithium in THF (Scheme 1).
Scheme 1. Preparation of hexahydrosilaphenalenes by the reaction of trilithiocyclododecatriene with trichlorosilane.
We wish to report herein halogen- and alkoxy-substituted hexahydrosilaphenalenes 4 as shown in
Scheme 2. Compound 4 should be a useful building brock of the tricyclic compounds, e.g. reactions of
4 with LiAlH4 and n-butyllithium give 3a and 3f in high yields, respectively.
Scheme 2. Preparation and reactions of halogen and alkoxy substituted hexahydrosilaphenalenes
As shown in Figure 1,
compound 3 is obtained as a
racemic mixture of optical
isomers P and M1 having a chiral
C3 symmetric bowl shape
structure. Optical resolution of 3
is now in progress.
References
1. Petruhina, M. A.; Andreini, K. W.; Scott, L. T. Angew. Chem, Int. Ed. 2004, 43, 5477-5481.
3a (R = H, 20 %), 3b (R = Me, 40 %), 3c (R = Ph, 30 %), 3d (R = Mes, 12 %), 3e (R = 4-PhC6H4, 13 %)
Figure 1. Enantiomers of 3 and their schematic drawings.
P – 02
The 7th Asian Silicon Symposium
POSTER PRESENTATION ǀ Page 59
A Novel Bis-NHI-Stabilized Silyliumylidene and its Reactivity
towards Transition Metals
Franziska Hanusch and Shigeyoshi Inoue*
Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research Center, Technische
Universität München, Lichtenbergstraße 4, 85748 Garching bei München, Germany
In the family of low-coordinate silicon compounds, two of the youngest family members are
silyliumylidenes and silylones. Sterically shielding and electron donating ligands are a game changer,
when it comes to stabilizing those highly reactive species. Bis-N-heterocyclic imines (bis-NHIs) are
particularly strong σ- and π-donors that create highly electron rich and therefore nucleophilic metal
centers without showing π-acceptor abilities - like NHCs do. While the number of silyliumylidenes and
silylones has grown over the last years, their reactivity towards transition metals and in terms of
catalysis is still in its infancy.1, 2
Figure 1. Reactivity of bis-NHI-stabilized silyliumylidene 1 towards transition metal reagents.
Herein, we present our latest results regarding the reactivity of bis-NHI-stabilized silyliumylidene 1
towards transitions metals for coordination chemistry and beyond.
References
1. P. Jutzi, A. Mix, B. Rummel, W. W. Schoeller, B. Neumann and H.-G. Stammler, Science, 2004, 305, 849. (b) K.
Leszczyńska, A. Mix, R. J. F. Berger, B. Rummel, B. Neumann, H.-G. Stammler and P. Jutzi, Angew. Chem. Int. Ed. 2011,
50, 6843. (c) K. C. Mondal, H. W. Roesky, M. C. Schwarzer, G. Frenking, B. Niepötter, H. Wolf, R. Herbst-Irmer and D.
Stalke, Angew. Chem. Int. Ed., 2013, 52, 2963.
2. Reviews: (a) S. Yao, Y. Xiong and M. Driess, Acc. Chem. Res., 2017, 50, 2026. (b) P. K. Majhi, T. Sasamori, Chem. Eur.
J. 2018, 24, 9441. (c) S. L. Powley, S. Inoue, Chem. Rec. 2019, doi:10.1002/tcr.201800188. (d) T. Ochiai, D. Franz, S.
Inoue, Chem. Soc. Rev. 2016, 45, 6327
P – 03
Nanyang Technological University
POSTER PRESENTATION ǀ Page 60
Synthesis of new laddersiloxanes with reactive functional groups
for applications in supported catalysis
Yujia Liu, Kazuki Onodera, Peiyao Zhang, Nobuhiro Takeda, Armelle Ouali, Masafumi Unno
Gunma University Initiative for Advanced Research (GIAR) - International Open Laboratory with Montpellier
France – Institute Charles Gerhardt (CNRS/ENSCM/UM),
Department of Chemistry and Chemical Biology, Faculty of Science and Technology,
Gunma University, Kiryu 376-8515, Gunma, Japan
In recent years, increasing demands have been observed on the development of materials with high
function like thermal stability, low-k value, or high refractive index. Among the possible candidates of
these materials, silsesquioxanes (RSiO3/2 where R can be hydrogen, alkyl or aryl groups) with well-
defined structures is one of the most promising compounds. Especially, the cubic polyhedral
oligosilsesquioxanes (T8) have been the most studied for various applications.1 In the past decade, the
synthesis, structure determination, and thermal properties of ladder oligosilsesquioxanes with defined
ladder structures (named “laddersiloxane”) have been reported as well.2 By introducing reactive
substituents, the resulting laddersiloxanes can potentially be used as nanometer-scale precursors and
building blocks in electronic materials, medicinal chemistry and catalysis. Our work is focusing on the
synthesis of high-ordered nano-sized laddersiloxanes as building blocks for new supported catalysts
and exploitation of their catalytic activities. We succeeded in preparing new laddersiloxanes bearing
divinyl, tetravinyl and allyl functional groups and carrying out hydrosilylation reactions of these
synthesized laddersiloxanes as well.
References
1. D. B. Cordes, P. D. Lickiss, F. Rataboul, Chem. Rev. 2010, 110, 2081-2173.
2. (a) M. Unno, A. Suto, T. Matsumoto, Russ. Chem. Rev. 2013, 82, 289-302; (b) H. Endo, N. Takeda, M. Unno,
Organometallics 2014, 33, 4148-4151.
P – 04
The 7th Asian Silicon Symposium
POSTER PRESENTATION ǀ Page 61
Bisboryloxysilylene: Synthesis and Reactivity
Lu Ying, Simon Aldridge*
Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Park Road,
Oxford OX1 3QR
Silicon is the second most abundant element in the Earth’s crust after oxygen, consisting of ca. 28%
by mass, making it a sustainable and easily obtainable element on which to base new main group bond
activation processes. One type of low valent silicon species, silylenes (R2Si:), have attracted much
attention in recent decades, starting with a landmark report of an N-heterocyclic silylene in 1994.1 The
acyclic subspecies, however, had not been reported until 2012.2 Although challenging to synthesize,
two-coordinate acyclic silylenes have shown interesting reactivity towards small molecules due to the
relatively narrow HOMO-LUMO gap typically encountered.2a
Herein, an acyclic silylene bearing bulky ancillary boryloxyl ligands has been synthesized (1, Fig
1),3 and its reactivity studied. This system represents the first example of a two-coordinate acyclic
silylene with two oxygen-based ligands, and readily activates carbon dioxide and water to give the
Si(IV) products (2 and 3, Fig 1) respectively. Upon reacting with triphenylphosphine oxide, the silylene
abstracts the oxygen atom from the phosphine oxide, forming the corresponding silanone as its
phosphine oxide adduct (4, Fig 1).
Scheme 1. Reactivity of bisboryloxysilylene 1
References:
1. M. Denk, R. Lennon, R. Hayashi, R. West, A. V. Belyakov, H. P. Verne, A. Haaland, M. Wagner, N. Metzler, J. Am.
Chem. Soc. 1994, 116, 2691-2692.
2. (a) A. V. Protchenko, K. H. Birjkumar, D. Dange, A. D. Schwarz, D. Vidovic, C. Jones, N. Kaltsoyannis, P. Mountford,
S. Aldridge, J. Am. Chem. Soc. 2012, 134, 6500-6503; b) B. D. Rekken, T. M. Brown, J. C. Fettinger, H. M. Tuononen, P.
P. Power, J. Am. Chem. Soc. 2012, 134, 6504-6507.
3. Y. K. Loh†, L. Ying†, M. Á. Fuentes, D. C. H. Do, S. Aldridge, Angew. Chem. Int. Ed. 2019, 58, 4847-4851. (†Equal
contribution)
N
B
N
O
Dipp
Dipp
SiO B
N
N
Dipp
Dipp
bisboryloxysilylene, 1
2 CO2, -CO
hexane, rt
N
B
N
O
Dipp
Dipp
SiO B
N
N
Dipp
Dipp
H OH
N
B
N
O
Dipp
Dipp
SiO B
N
N
Dipp
Dipp
OO
O
2 PPh3=O, -PPh3
benzene, rt
carbonate, 2
O–H activation, 3
H2Ohexane, rt
silanone, 4
N
B
N
O
Dipp
Dipp
SiO B
N
N
Dipp
Dipp
O
OPPh3
P – 05
Nanyang Technological University
POSTER PRESENTATION ǀ Page 62
Approach to ViPh-Janus cube and
synthesis of tetrafunctional Double-Decker siloxanes
Mana Kigure, Yujia Liu, Armelle Ouali, Nobuhiro Takeda, Masafumi Unno
Department of Chemistry and Chemical Biology, Faculty of Science and Technology,
Gunma University, and Gunma University Initiative for Advanced Research (GIAR),
Kiryu 376-8515, Japan
Cage octasilsesquioxanes (T8) are the most studied among all of silsesquioxanes due to their
high degree of symmetry with functional groups in each octant, their nanometer size, and numbers of
preparation methods. In particular, “Janus cube” octasilsesquioxane,1 which is a nanometer-scale Janus
particle with two kinds of substituents, was synthesized by the cross-coupling reaction of a “half-cube”
cyclic silanolate salt with another half-cube cyclic fluorosiloxane in our laboratory1. However, Janus
cubes with reactive substituents have been scarcely synthesized yet.
Therefore, we tried to synthesize Janus cube with vinyl groups. Vinyl group can be used for
hydrosilylation and addition reaction, thus they are useful industrial application. We tried to synthesize
the target compound by cross-coupling reaction (Figure. 2).
On the other hand, we were also trying to use silsesquioxanes for building blocks for complex
inorganic-organic hybrid materials. We succeeded in the synthesis of tetravinyl- and tetraallyl-
substituted closed Double-Decker siloxanes (Figure 3, Figure 4) and they could successfully undergo
hydrosilylation quantitatively.2
Figure 1. Janus cube Figure 2. Approach to ViPh-Janus cube
Figure 3. DDSQ-Vinyl4 Figure 4. DDSQ-Allyl4
References
1. N. Oguri, Y. Egawa, N. Takeda, and M. Unno, Angew. Chem. Int. Ed., 55, 9336 (2016).
2. Y. Liu, N. Takeda, A. Ouali, and M. Unno, Inorg. Chem., 58, 4093-4098 (2019).
P – 06
The 7th Asian Silicon Symposium
POSTER PRESENTATION ǀ Page 63
Construction of Novel Group-14 Species
Aming Tautomerizable Heavy Carbonyl Compounds
Mariko Yukimoto, Min Woo Jo, Norihiro Tokitoh
Institute for Chemical Research, Kyoto University,
Gokasho, Uji, Kyoto 611-0011, Japan
Kinetic stabilization afforded by bulky substituents has been successfully applied to the synthesis and
isolation of highly reactive species such as doubly and triply bonded heavier main group element
compounds.1 Although keto-enol tautomerization reaction is one of the most important concepts in
organic chemistry,2 tautomerization has never been explored for the so-called heavy ketones and heavy
amides (double-bond compounds between heavier group 14 and 16 elements) due to the difficulty in
the synthesis and steric protection of the reactive heavy carbonyl bonds having an alpha-hydrogen.
In this research, we first examined the synthesis of overcrowded aminosilanes as a precursor for
tautomerizable heavy amides, and aminosilane 1 was obtained by the reaction of BbtSiH3 with t-
BuNHLi. We are now investigating the transformation of aminosilane 1 into the expected heavy amides
and related low-coordinated silicon compounds. In relation to the chemistry of heavy amides, we
examined the synthesis of heavy ketones having an alpha-hydrogen. Thus, the reaction of methylene-
substituted germylene 2 with elemental selenium gave the corresponding germaneselone 3. The
syntheses, structures and reactions of 2 and 3 as well as those of aminosilane 1 will be discussed.
References
1. Tokitoh, N., Okazaki, R. In The Chemistry of Organic Silicon Compounds, Vol. 2; Rappoport, Z., Apeloig, Y., Eds.; John
Wiley & Sons: Chichester, 1998; pp 1063–1103; Weidenbruch, M. In The Chemistry of Organic Silicon Compounds, Vol.
3; Rappoport, Z., Apeloig, Y., Eds.; John Wiley & Sons: Chichester, 2001; pp 391–428.
2. In Tautomerism: Methods and Theories; Antonov, L. Ed.; Wiley-VCH Verlag GmbH & Co.: Weinheim, 2014; pp 1–20.
P – 07
Nanyang Technological University
POSTER PRESENTATION ǀ Page 64
Reactivity of an Iminodisilene
Richard Holzner and Shigeyoshi Inoue*
Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research Center, Technische
Universität München, Lichtenbergstraße 4, 85748 Garching bei München, Germany
E-Mail: [email protected]
The synthesis of Mes2Si=SiMes2, the first compound containing a Si=Si double bond by West and
coworkers in 1981 was a milestone in modern main group chemistry.1 This disilene readily reacts with
white phosphorus in a selective fashion, resulting in the two central Si-atoms bridged by two P-atoms.2
In recent years, our group presented an iminodisilene,3 bearing strongly π-donating N-heterocyclic
imino (NHI) substituents4 and sterically demanding Si(TMS)3 groups. Although interesting reactivities
towards oxidation reagents were observed,5 the investigation of this disilene is limited by its thermal
instability, especially in solution. Therefore, we modified the silyl substituents to SitBu2Me and obtained
the stable iminodisilene 1.
Scheme 1: Synthesis and characterization of compounds 2 and 3.
Here, we present the one-electron oxidation of iminodisilene 1 furnishing the cationic radical 2
(Scheme 1). Furthermore, the reaction product of 1 with white phosphorus 3 will be shown. Compound
3 exhibits an unprecedented structure. The two former sp2 Si-atoms are bridged by a P4 tetrahedron. In
addition, further reactivity of iminodisilene 1 will be presented and discussed.
References
1. R. West, M. J. Fink, J. Michl, Science 1981, 214, 1343.
2. M. Driess, A. D. Fanta, D. R. Powell, R. West, Angew. Chem. Int. Ed. Engl. 1989, 28, 1038-1040; Angew. Chem. 1989,
101, 1087-1088.
3. D. Wendel, T. Szilvási, C. Jandl, S. Inoue, B. Rieger, J. Am. Chem. Soc. 2017, 139, 9156-9159.
4. T. Ochiai, D. Franz, S. Inoue, Chem. Soc. Rev. 2016, 45, 6327-6344.
5. D. Wendel, T. Szilvási, D. Henschel, P. J. Altmann, C. Jandl, S. Inoue, B. Rieger, Angew. Chem. Int. Ed. 2018, 57, 14575-
14579; Angew. Chem. 2018, 130, 14783-14787.
P – 08
The 7th Asian Silicon Symposium
POSTER PRESENTATION ǀ Page 65
Reduction of 1,2-Dibromodisilene Bearing the Bulky Eind Groups
Ryoma Ohno,a Alfredo Rosas-Sanchez,b Daisuke Hashizume,b Tsukasa Matsuoa,*
aDepartment of Applied Chemistry, Faculty of Science and Engineering, Kindai University,
3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502, JAPAN bRIKEN Center for Emergent Matter Science (CEMS),
2-1 Hirosawa, Wako, Saitama 351-0198, JAPAN
[email protected], [email protected]
We have focused on exploring the chemistry of unsaturated compounds of the heavier group 14
elements employing the bulky aryl groups based on a rigid fused-ring 1,1,3,3,5,5,7,7-octa-R-substituted
s-hydrindacen skeleton, called “Rind” groups.1,2
Here we present the reduction reaction of 1,2-dibromodisilene supported bythe bulky Eind groups,
(Eind)BrSi=SiBr(Eind) (Eind = 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl).3A halogen-substituted
three-membered-ring unsaturated silicon compound, cyclotrisilene, Si3Br(Eind)3, has been obtained as
pale yellow crystals by the reaction of the 1,2-dibromodisilene with 1 equiv of lithium metal. The
molecular structure of the cyclotrisilene has been determined by X-ray crystallography. A new
tetrasilacyclobutadiene, Si4(Eind)4, has also been synthesized by a similar reaction using 2 equiv of
lithium metal.The Eind-substituted tetrasilacyclobutadiene is found to be more thermally stable than
the less bulky EMind-substituted tetrasilacyclobutadiene, Si4(EMind)4.4We are now investigating the
reactivities of the unsaturated cyclic siliconcompounds.
References
1. T. Matsuo, N. Hayakawa, Science and Technology of Advanced Materials (STAM) 2018, 19, 108–129.
2. T. Matsuo, K. Tamao, Bull. Chem. Soc. Jpn. 2015, 88, 1201–1220 (Inside Cover).
3. K. Suzuki, T. Matsuo, D. Hashizume, K. Tamao, J. Am. Chem. Soc. 2011, 133, 19710–19713.
4. K. Suzuki, T. Matsuo, D. Hashizume, H. Fueno, K. Tanaka, K. Tamao, Science 2011, 331, 1306–1309.
P – 09
Nanyang Technological University
POSTER PRESENTATION ǀ Page 66
Synthesis of Hexahydroboraphenalene by Silicon-Boron
Exchange
Satoshi Ozaki, Shohei Oka, Takumi Sugino, Kenkichi Sakamoto*
Department of Chemistry, Faculty of Science, Shizuoka University
836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
Boraphenalene 1 is receiving theoretical attention because the
compound is an isoelectronic molecule of phenalenyl cation
having aromatic character.1 However, synthetic studies aimed at
formation of boraphenalene structures have not been reported so
far, except for synthesis of a saturated tricyclic compound 3 by H.
C. Brown.2
In this work, we have synthesized hexahydroboraphenalene 2 as a starting material of 1 by triple
silicon-boron exchange. The Si-B metathesis is known to be a powerful method for the synthesis of
organoboron compounds and some interesting molecules are obtained by this reaction.4 Thus, as a
direct precursor of 2, we have employed tris(trimethylsilyl)cyclododecatriene (6), that is obtained by
the reaction of tribromide 4 with tBuLi followed by the addition of Me3SiCl in a quantitative yield.
The reaction of 6 with
tribromoborane to give 2 was carried
out in CDCl3 at rt and monitored by 1H
NMR as shown Figure 1. The 1H
NMR peaks of 6 are disappeared
within 4 hours and new peaks are
found at 6.63, 2.39, 2.32, and 0.59.
The new peaks are successfully
identified as protons of 2 and
trimethyl-bromosilane by comparing
the observed values with calculated
ones. The yield of 2 is 70%
determined by 1H NMR.
References
1. For example: Aihara, J. Bull. Chem. Soc.
Jpn., 2008, 81, 241-247.
2. Brown, H. C., Negishi, E. J. Am. Chem. Soc., 1967, 89, 5478.
3. Untch, K. G., Martin, D. L., J. Am. Chem. Soc., 1965, 87, 3518.
4. For example: Gross, U. Chem. Ber., 1987, 120, 991.
Figure 1. Spectral change during the reaction of 6 with BBr3 to give 2 and
Me3SiBr. Values in parentheses are calculated chemical shifts (DFT, B3LYP,
6-31G*).
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The 7th Asian Silicon Symposium
POSTER PRESENTATION ǀ Page 67
Synthetic Studies on Silabenzenyl Anion
Shingo Tsuji,a,* Yoshiyuki Mizuhata,a Norihiro Tokitoha
aInstitute for Chemical Research, Kyoto University, Gokasho Uji-city, Kyoto, Japan 611-0011
Recently, heavier group 14 element analogues of phenyl anions, ‘metallabenzenyl anions,’ 1− and 2−
were synthesized inreactions of Tbt-substituted stable metallabenzenes 3 and 4 with KC8, respectively
(Scheme 1, left).1,2 Experimental and calculational results revealed they have characters as both
aromatic compounds and divalent species (metallylenes).
In general, group 14 elements have a tendency to get stable as divalent species as the period goes
down. Comparing 1− and 2−, the former is more aromatic while the latter is more divalent, reflecting the
tendency (Scheme 1, right).
Scheme1. Left: Synthesis of Germa-and Stannabenzenyl Anions. Right: Resonance Contributions.
Asilicon analogue, ‘silabenzenyl anion,’ 5− is predicted to possess more increased aromatic character
than that of 1−, but the synthesis and elucidation of the character and reactivity have not yet been
achieved. Therefore, we attempted the systhesis of 5− to gain fundamental insights about
metallabenzenyl anions.
The reaction of silabenzene 6 with KC8 resulted in the generation of dianion 72−, instead of the
expected 5−, without the elimination of the bulky substituent on the silicon atom (Scheme 2). This result
reflects the influences of central heavier group 14 atoms on the elimination step of the aryl group.
Scheme 2. Attempted Synthesis of Silabenzenyl Anion 5−.
References
1. Mizuhata, Y.; Fujimori, S.; Sasamori, T.; Tokitoh, N. Angew. Chem. Int. Ed. 2017, 56, 4588.
2. Fujimori, S.; Mizuhata, Y.; Tokitoh, N. Chem. Eur. J. 2018, 24, 17039.
P – 11
Nanyang Technological University
POSTER PRESENTATION ǀ Page 68
Synthesis of Hexahydrosilaphenalene by Intramolecular Triple
Metathesis of Tri(1-cyclobutenyl)silane
Shunya Nagata, Junghun Lee, Shohei Oka, Takumi Sugino, and Kenkichi Sakamoto*
Department of Chemistry, Faculty of Science, Shizuoka University
836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
Phenalenyl is an odd alternant hydrocarbon having a non-bonding orbital and its derivatives are
investigated as the basis for materials science in the field of molecular electronics and photonics.1
However, only a few compounds of heteroatom substituted phenalenyls and phenalenes are known so
far. Recently, we have developed a new method to synthesize of hexahydrosilaphenalene 1 as a precusor
of silaphenalene. As shown in eq. 1, a reaction of trichlorosilanes with trilithiocyclododecatriene 3
derived from the corresponding tribromide 2 gives 1 in moderate yields (R = H, Me, Ph, 4-Ph-C6H4,
and 2-Me-C6H4, Mes). Compound 1 has a unique molecular shape like a cocktail-glass with a local
chiral C3 symmetry. We wish to report herein other synthetic methods of 1 by intramolecular triple
metathesis of tri(hexa-1,5-dien-2-yl)silane 4 and tri(1-cyclobutenyl)silane 5 using Grubbs' catalysts as
shown in eq 2, respectively.
Compound 4 was obtained by the reaction of hexa-1,5-dien-2-yllithium2 with trichlorosilanes (R =
H, Me, OMe). The compound expected to be a straightforward precursor of 1 and allowed to react with
various Grubbs' catalysts (eq. 2); however, formation of the desired product 1 does not occur completely.
DFT calculations (B3LYP, 6-31G*) reveal that the metathesis is not thermodynamically favorable due
to the strain of silicon containing fused ring systems.
Preparation of compound 5 was accomplished by the reaction of 1-cyclobutenyllithium3 with
trichlorosilanes (R = H, Me, Ph, 2-Me-C6H4). We have investigated the isomerization of the derivatives
of 5 in the presence of various Grubbs' catalysts systematically and found that the methyl, phenyl, and
2-methylphenyl substituted compounds give the desirable product 1. For example, reaction of 5 (R =
Ph) with the second-generation Grubbs' catalyst (30 mol%) is resulted in 56% conversion of 5 and gives
1 in 81% yield based on the conversion.
References
1. Goto, K.; Kubo, T.; Yamamoto, K.; Nakasuji, K.; Sato, K.; Shiomi, D.; Takui, T.; Kubota, M.; Kobayashi, T.; Yakushi,
K.; Ouyang, J. J. Am. Chem. Soc. 1999, 121, 1619.
2. Peterson, P. E.; Nelson, D. J.; Risener, R. J. Org. Chem. 1986, 51, 2381.
3. Jayathilaka, L. P.; Deb, M.; Standaert, R. F. Org. Lett. 2004, 6, 3659.
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The 7th Asian Silicon Symposium
POSTER PRESENTATION ǀ Page 69
Controllable Synthesis and Application of Dendritic Fibrous
Nanosilica-Based Hybrid Nanomaterials
Soeun Jung, Ngoc Minh Tran, and Hyojong Yoo*
Department of Chemistry, Hallym University
Chuncheon, Gangwon-do, Republic of Korea, 24252
Morphologically unique silica nanoparticles can be used as effective templates to prepare hybrid
materials, which are highly applicable in a variety of areas. In this work, dendritic fibrous nanosilica
(DFNS) with low density, high stability and permanent porosity is successfully employed as a template
to grow gold nanoparticles and/or zinc-based coordination polymer particles (Zn-CPPs) to fabricate
DFNS-based hybrid nanomaterials. Au nanodots are initially anchored on the surface of the DFNS
through the selective reduction of Au ions to form DFNS/Au dots. A seed-mediated growth method is
used to controllably grow Au nanoparticles on the DFNS/Au dots to generate DFNS-Au nanoparticles
nanohybrids (DFNS/Au). The DFNS and DFNS/Au hybrids subsequently employed as efficient
templates to grow Zn-CPPs via solvothermal process, and this leads to the formation of DFNS@Zn-
CPPs and DFNS/Au@Zn-CPPs core-shell nanohybrids, respectively. The obtained hybrid
nanomaterials exhibit an enhancement of catalytic performance.
P – 13
Nanyang Technological University
POSTER PRESENTATION ǀ Page 70
Synthesis and characterization of a well-defined sized Ladder-
structure silsesquioxanes using intramolecular cyclization
reaction mediated by B(C6F5)3
Thanawat Chaipraserta, Nobuhiro Takedaa and Masafumi Unnoa
a Department of Materials and Bioscience, Graduate School of Science and Technology, Gunma University, 1-
5-1 Tenjin-cho, Kiryu, 376-8515, Japan
Symmetrical Ladder-type silsesquioxanes, including T4D4, and T4D2, and unsymmetrical one T4D3
were, for the first time, synthesized by B(C6F5)3 using [Ph-Si(O)-SiMe2H]4 as the starting materials. In
this work, the products were investigated and characterized using multinuclear NMR spectroscopy,
mass spectrometry, and CHN analysis. The structures and thermal properties of products were
investigated using x-ray crystallography, DSC, and TGA. According to our finding, we found that T4D4
and T4D2 are white crystalline products, whereas T4D3 is colorless oil.
Reference
1. M. Unno, H. Endo, N. Takeda, Heteroatom Chem., 2014, pp 525–532
13. Robin P., Alan R. B., Alexander A. K., Mateusz B. P., Simon J. C., and Peter G. T., Organometallics, 2013, 32 (6), pp
1732–1742
14. Julian C., Sławomir R., James A. C., Witold F., Marek C., Jan K., and Krzysztof K., Organometallics, 2005, 24 (25), pp
6077–6084
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The 7th Asian Silicon Symposium
POSTER PRESENTATION ǀ Page 71
Cleavage of a P=Si Double Bond Mediated by NHC
Tomohiro Obayashi,a Kazuya Sadamori,a Takayoshi Yoshimura,b Miho Hatanaka,b Tsukasa Matsuoa,*
aDepartment of Applied Chemistry, Faculty of Science and Engineering, Kindai University,
3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502, JAPAN bNara Institute of Science atd Technology (NAIST), 8961-5 Takayama, Ikoma, Nara, 630-0192 JAPAN
[email protected], [email protected]
We have studied a variety of low-coordinate compounds of main group elements as well as transition
metals by taking advantage of the steric protection with fused-ring bulky Rind groups (Rind =
1,1,3,3,5,5,7,7-octa-R-substituted s-hydrindacen-4-yl).1 Recently, we reported the metathesis-like
reaction of the Rind-substituted diphosphenes, (Rind)P=P(Rind) (Rind = Eind and EMind),2 with two
moleculesof N-heterocyclic carbene (NHC), thus leading to the formation of the NHC-coordinated
phosphinidene adducts, NHC→P(Rind).3 We examined the reaction mechanism of the NHC-mediated
P=P double bond-breakingof the diphosphenes using DFT calculations.
Here we report a unique P=Si double bond cleavage reaction of the phosphasilene with NHC. The
EMind-substituted phosphasilene, (EMind)P=SiPh(EMind)(EMind = 1,1,7,7-tetraethyl-3,3,5,5-
tetramethyl-s-hydrindacen-4-yl),4 reacted with two equivalents of NHC to afford a mixture of the NHC-
phosphinidene adduct, NHC→P(EMind), and the silicon(IV) compound, which were characterized
spectroscopically and crystallographically. We present the DFT computations on the mechanism of the
NHC-mediated P=Si double bond cleavage.
References
1. T. Matsuo, K. Tamao, Bull. Chem. Soc. Jpn. 2015, 88, 1201–1220 (Inside Cover).
16. B. Li, S. Tsujimoto, Y. Li, H. Tsuji, K. Tamao, D. Hashizume, T. Matsuo, Heteroat. Chem. 2014, 25, 612–618.
17. N. Hayakawa, K. Sadamori, S. Tsujimoto, M. Hatanaka, T. Wakabayahsi, T. Matsuo, Angew. Chem. Int. Ed. 2017, 56,
5765–5769.
18. B. Li, T. Matsuo, T. Fukunaga, D. Hashizume, H. Fueno, K. Tanaka, K. Tamao, Organometallics 2011, 30, 3453–3456.
P – 15
Nanyang Technological University
POSTER PRESENTATION ǀ Page 72
Transition Metal-Capped Silicon Cage Si8Ar6L2 Stabilized by
Multiple Si–Si σ Bonding
Yang Li,a Jianying Zhang,a and Chunming Cuia,b
a State Key Laboratory of Elemento-Organic Chemistry and College of Chemistry, Nankai University,
Tianjin 300071, People’s Republic of China b Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072,
People’s Republic of China
Main group element compounds of the formula (ER)n (n 4) have long been of great interest because
of their unique bonding, structures and chemical and physical properties in comparison with their
carbon congeners. For example, group 14 (ER)6 tends to adopt polyhedral structures with E−E -bonds
rather than to form the aromatic benzene analogues,1 which are probably the most challenging synthetic
targets in group 14 element chemistry. Despite the great interest in organosilicon clusters, incorporation
of transition metals into silicon clusters have been particularly attractive for the development of
catalysis and materials2.
Herein, we reported that, by the introduction of silylene moieties on the skeleton of an organosilicon
cluster, it is possible to construct well-defined metal-capped silicon clusters by the reaction of the silicon
cluster with simple low-valent organometallic precursors under normal conditions (Scheme 1).
Remarkably, the isomerization of the silicon skeleton in the presence of transition metals was observed.
X-ray structural analysis and DFT calculations disclosed the novel geometry of the metal in the cages
with significant Si–Si σ-bonding.
Scheme 1. Synthesis of transition metal-capped Si8L2Ar2 silicon cage 3 and 43.4
References
1. (a) Sekiguchi, A.; Yatabe, T.; Kabuto, C.; Sakurai, H. J. Am. Chem. Soc. 1993, 115, 5853−5854. (b) Abersfelder, K.;
White, A. J. P.; Rzepa, H. S.; Scheschkewitz, D. Science 2010, 327, 564−566. (c) Abersfelder, K.; White, A. J. P.; Berger,
R. J. F.; Rzepa, H. S.; Scheschkewitz, D. Angew. Chem., Int. Ed. 2011, 50, 7936−7939. (d) Abersfelder, K.; Russell, A.;
Rzepa, H. S.; White, A. J. P.; Haycock, P. R.; Scheschkewitz, D. J. Am. Chem. Soc. 2012, 134, 16008−16016. (e) Tsurusaki,
A.; Iizuka, C.; Otsuka, K.; Kyushin, S. J. Am. Chem. Soc. 2013, 135, 16340−16343.
2. (a) Kumar, V.; Briere, T. M.; Kawazoe, Y. Phys. Rev. B 2003, 68, 155412–155421. (b) Khanna, S. N.; Rao, B. K.; Jena,
P.; Nayak, S. K. Chem. Phys. Lett. 2003, 373, 433–438.
3. Li, Y.; Li, J.; Zhang, J.; Song, H.; Cui, C. J. Am. Chem. Soc. 2018, 140, 1219–1222.
4. Sen, S. S.; Roesky, H. W.; Henn, D.; Stern, J.; Stalke, D. J. Am. Chem. Soc. 2010, 132, 1123–1126
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POSTER PRESENTATION ǀ Page 73
Co-oligomerizations of 2,5-Dibromo-1,1-disubstituted-3,4-
diphenyl-siloles with 4,4'-(Hexafluoroisopropylidene)diphenol or
4,4'-Biphenol and their Characteristics
Jong Wook Lim, Young Tae Park*
Department of Chemistry, Keimyung University, Daegu 42601, Korea
2,5-Dibromo-1,1-disubstitued-3,4-diphenyl-siloles (e.g, diisopropyl, dihexyl) as monomers were
prepared by intramolecular reductive cyclization reactions of disubstituted-bis(phenylethynyl)silanes
using lithium naphthalenide, anhydrous ZnCl2, and N-bromosuccinimide (NBS), respectively.
Co-oligomerization reactions of 2,5-dibromo-1,1-disubstitued-3,4-diphenyl-siloles with 4,4'-
(hexafluoroisopropylidene)diphenol or 4,4'-biphenol were carried out by the nucleophilic substitution
reaction of two bromine groups in the presence of potassium carbonate under the co-solvent of N-
methyl-2-pyrrolidinone (NMP) and toluene by azeotrope using Dean-Stark trap.
The crude oligomeric products were purified by extraction using the solvents of tetrahydrofuran and
dichloromethane, and washed with deionized water. The oligomeric product materials were
characterized by 1H, 13C, and 29Si NMR as well as GPC. We also studied the photoelectronic properties
by UV-vis absorption, excitation, and fluorescence emission spectroscopic methods, in particular.
Scheme 1. Co-oligomerizations of 2,5-dibromo-1,1-disubstituted-3,4-diphenyl-siloles
with 4,4'-(hexafluoroisopropylidene)diphenol.
Acknowledgment
This work was supported by the Basic Science Research Program through the National Research Foundation of
Korea (NRF) grant funded by the Ministry of Education of the Republic of Korea (NRF-2017R1D1A3B03028014).
P – 17
Nanyang Technological University
POSTER PRESENTATION ǀ Page 74
Synthesis of 1,1-Disubstituted-2,5-bis{(trimethylsilyl)ethynyl}-3,4-
diphenyl-siloles and their Characteristics
Jong Wook Lim, Young Tae Park*
Department of Chemistry, Keimyung University, Daegu 42601, Korea
2,5-Dibromo-1,1-disubstituted-3,4-diphenyl-siloles (e.g, diethyl, dihexyl, diisopropyl) were
prepared by reactions of disubstituted-bis(phenylethynyl)silanes with lithium naphthalenide, anhydrous
ZnCl2, and N-bromosuccinimide (NBS), respectively.
Palladium chloride, copper iodide, and triphenylphosphine as co-catalyst were used to replace two
bromine groups of the prepared siloles with trimethylsilylacetylene (TMSA) under the reaction
condition of diisopropylamine as solvent. The crude products were refined by recrystallization or
column chromatography in the solvent of hexane.
The product materials were characterized by 1H, 13C, and 29Si NMR. We also studied the
photoelectronic properties of the materials by UV-vis absorption, excitation and fluorescence emission
spectroscopic methods.
Scheme 1. Synthesis of 2,5-bis{(trimethylsilyl)ethynyl}-3,4-diphenyl-siloles.
Acknowledgment
This work was supported by the Basic Science Research Program through the National Research Foundation of
Korea (NRF) grant funded by the Ministry of Education of the Republic of Korea (NRF-2017R1D1A3B03028014).
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The 7th Asian Silicon Symposium
POSTER PRESENTATION ǀ Page 75
Nickel-Catalyzed Selective Cross-Coupling of Chlorosilanes with
Organoaluminum Reagents
Yuki Naganawa,* Guo Haiqing, Kei Sakamoto, Yumiko Nakajima*
Interdisciplinary Research Center for Catalytic Chemistry
National Institute of Advanced Industrial Science and Technology
Tsukuba, Ibaraki 305-8565, Japan
[email protected], [email protected]
Chlorosilanes are important raw materials for the production of various organosilicon materials, such
as silicones and silane coupling reagents. The performance of the organosilicon materials is highly
dependent on the substituent groups on the silicon atom; thus, the synthesis of chlorosilanes bearing
various organic substituents (organochlorosilanes) occupies a fundamental position in the silicon
industry. One of common preparative methods to access organochlorosilanes is alkylation and arylation
of chlorosilanes with organometallic reagents. However, the use of the highly reactive organometallic
reagents, which often suffer from the low reaction selectivity, is a troublesome issue. Thus, the
development of new methods for the precise introduction of organic substituents into chlorosilanes is
of great importance.
Transition metal-catalyzed cross-coupling reactions of organohalides offer a general synthetic route
to the formation of C–C bonds. In contrast to the significant advances in this field, the corresponding
catalytic reactions of halosilanes for the formation of Si–C bonds remain relatively unexplored.1,2 In
this context, we have thus far reported nickel-catalyzed silyl-Heck reaction of chlorosilanes with
styrenes as the first example of the direct catalytic transformation of chlorosilanes as cheap and versatile
silicon feedstocks.3 To expand a scope of coupling partners in the reactions, we developed nickel-
catalyzed cross-coupling reactions of chlorosilanes with organoaluminum reagents.4
The reaction of dichlorosilanes with 2 equivalents of trialkylaluminum reagents proceeded to provide
the corresponding alkylated products in the presence of Ni(cod)2 (5 mol%) and PCy3 (10 mol%).
Monoalkylated product was predominantly formed accompanied by the dialkylated product as a minor
product. Trichlorosilanes underwent selective double substitution to furnish the corresponding
monochlorosilanes. Overall, the selective synthesis of a series of alkylmonochlorosilanes from di- and
trichlorosilanes was achieved using the present catalytic systems (Figure 1).
Figure 1. Nickel-catalyzed cross-coupling reaction of di- and trichlorosilanes with trialkylaluminum.
References
1. Cinderella, A. P.; Vulovic, B.; Watson, D. A. J. Am. Chem. Soc. 2017, 139, 7741–7744.
19. Vulovic, B.; Cinderella, A. P.; Watson, D. A. ACS Catal. 2017, 7, 8113–8117.
20. Matsumoto, K.; Huang, J.; Naganawa, Y.; Guo, H.; Beppu, T.; Sato, K.; Shimada, S.; Nakajima, Y. Org. Lett. 2018, 20,
2481–2485.
21. Naganawa, Y.; Guo, H.; Sakamoto, K.; Nakajima, Y. ChemCatChem in press. (DOI: 10.1002/cctc.201900047)
P – 19
Nanyang Technological University
POSTER PRESENTATION ǀ Page 76
Hydrosilylation of Alkenes and Alkynes Catalyzed by Platinum Complexes Bearing SiS3-type Tripodal Tetradentate Ligand
Takatoshi Kageyama, Yutaka Komeda, Nobuhiro Takeda, and Masafumi Unno
Graduate School of Science and Techonology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515,
Japan
Transition metal complexes with tripodal tetradentate ligands have attracted much attention from the
viewpoints of activation of small molecules, catalytic activities, stabilization of reactive species, and so
on. There are many reports on tripodal tetradentate ligands containing amine or phosphine moieties as
donors, however, tripodal tetradentate silyl ligands tethered with three thioether moieties are very rare.
Complexes bearing the SiS3-type ligandsare expected to show high stability resulted from the strong
silicon–metal bond and ready ligand exchange with the thioether moieties due to their weak σ-donating
ability. Recently, we have synthesized platinum complexes1a and b bearing tripodal tetradentate SiS3-
type ligands, (2-RSC6H4)3Si-(R = t-Bu, i-Pr)1.
In this paper, we report the application of platinum complexes 1a, b bearing SiS3-type tripodal
tetradentate ligand to catalysts for hydrosilylation of alkenes and alkynes. Platinum complexes 1a, b
catalyzed hydrosilylation of 4-phenyl-1-butenewith HSi(OEt)3 to give the corresponding silane 3
selectively. The hydrosilylation of phenylacetylene catalyzed by platinum complexes 1a, b resulted in
the formation of the corresponding E-alkene 4 (58% for 1a, 70% for 1b) in good selectivity along with
α-alkene 5 (19% for 1a, 29% for 1b) (Scheme 2). The catalytic hydrosilylation using platinum
complexes 1a, b and the application to the hydrosilylation of various alkenes are now in progress.
Scheme 1. Platinum complexes 1a, 1b, 2a, 2b.
Scheme 2. Catalytic hydrosilylation using platinum complexes 1aand 1b.
References
1. N. Takeda, D. Watanbe, T. Nakamura, and M. Unno, Organometallics., 29, 2839-2841 (2010).
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POSTER PRESENTATION ǀ Page 77
Selective Hydrosilylation Reactions
of Allylic Compounds
Koya Inomata, Kazuhiko Sato, Yumiko Nakajima
Interdisciplinary Research Center for Catalytic Chemistry, National Institute of Advanced Industrial Science
and Technology (AIST)
Hydrosilylation reactions of alkenes are one of the most important methods for the synthesis of
various organosilicon compounds. Although Pt complexes are widely utilized as powerful and efficient
catalysts in these reactions, the systems still suffer from some drawbacks. One major problem is the
occurrence of the unwanted side reactions, which would cause the deleterious effects on the quality or
propreties of the final organosilicon materials. Thus, development of efficient hydrosilylation catalysts
is highly desired. In this study, we have focused on the hydrosilylation of allylic compounds, which are
significantly important for the production of silane coupling agents in the silicon industry. Pt-catalyzed
hydrosilylation of allylic compounds are often accompanied by the side products due to the Tsuji-Trost
reaction.1 In this context, we have developed novel Rh and Ru catalyst systems, which achieved
selective hydrosilylation reactions of allylchloride and allyl polyethylene glycols (allyl PEG).
Highly selective hydrosilylation reaction of allylchloride with HSiCl3 was achieved using a Rh
catalyst composed of [RhCl(cod)]2 (0.05 mol%) and a bidentate-phosphine ligand (0.1 mol%).2
Mechanistic study suggested the in-situ formation of a -allyl Rh complex, which further reacted with
HSiCl3 to form trichloro(propyl)silane as a side-product. We also demonstrated that a reaction catalyzed
by [RhCl(dppbzF)]2 (dppbzF = 1,2-bis(diphenylphosphino)-3,4,5,6-tetrafluorobenzene) selectively
furnished the corresponding hydrosilylated product, trichloro(3-chloropropyl)silane (1), at a catalyst
loading of 0.0005 mol%/Rh. This catalyst showed the high turn over number (TON) of 140,000
(Scheme 1).
Scheme 1. Rh-catalyzed hydrosilylation of allylchloride
Hydrosilylation reactions of PEGs are one of the key reactions to prepare functional PEGs, which
are potentially available as biorelated materials, polymer electrolytes, etc. Although conventional Pt
catalysts such as Speier’s catalyst and Karstedt’s catalyst can be utilized in these reactions,
isomerization reaction of allyl PEGs also proceeds.3 We are currently investigating the new catalyst
systems, which achieve high selective hydrosilylation reaction of allyl PEGs. The results will be also
discussed at the presentation.
References
1. P. Gigler, M. Drees, K. Riener, B. Bechlars, W. A. Herrmann, F. E. Kühn, J. Catal. 2012, 295, 1.
22. K. Inomata, K. Sato, Y. Nakajima, The CSJ Annual Meeting, 2D1-02, Hyogo, March 2019.
23. H. Shin, B. Moon, J. Polym. Sci. A. Polym. Chem. 2108, 56, 527.
P – 21
Nanyang Technological University
POSTER PRESENTATION ǀ Page 78
Preparation and Photochemical Property of a Heterobimetallic
AuPd2 Complex with Bridging Silylene Ligand
Kazuki Okuma,a Atsushi Kanda,a Yoshitaka Tsuchido,a Makoto Tanabea and Kohtaro Osakada a*
a Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology,
4259-R1-3, Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan.
The metal alloy which consists of two or more kinds of transition metal atoms shows unique
electronic states and the chemical properties, e.g. gold-palladium heterogeneous nanoparticles were
known as the efficient oxidation catalyst1). To investigate the related multinuclear metal complex is
important to gaining a well understanding of the role of these metals in the catalytic reaction. Only a
few examples of cationic AuPd complex, however, have been reported by Pignolet2) and Tanase3). The
biaryl silylene group (:SiAr2) have been applied as the ligand for the tetranuclear Pd complex4). In this
study, we have prepared a neutral trinuclear AuPd2 complex having diphenylsilylene group,
[AuPd2(PCy3)2(3-SiPh2)(-SC6H4CF3-4)] (3). Reaction of gold(I)-thiolate complex,
[Au(PCy3)(SC6H4CF3-4)] (1), with palladium dinuclear complex with bridging silylene ligand,
[{Pd(PCy3)2}{Pd(PCy3)}{-SiPh2}] (2), afforded complex 3 in 78% isolated yield (Scheme 1). This
reaction was progressed immediately at room temperature. An X-ray crystallographic study of 3
revealed that SiPh2 ligand is bounded to both two Pd and Au atoms. The Pd, Au, and Si atoms formed
a planar parallelogram core. The Au-Si bond length is 2.61 Å which is much longer than that of reported
gold silyl complex (2.36 Å) 5). Complex 3 exhibits green color in the solid state and solution (max =
611 nm, in toluene), which is caused by the intramolecular Charge-Transfer (CT) excitation between
Pd2S unit (HOMO) and AuSi unit (LUMO) based on the DFT calculations. The electron-withdrawing
silylene ligand induced the unique photochemical properties of complex 3. We will also discuss the
reactivity of AuPd2 trinuclear complex 3 with various organic molecules.
Scheme 1. Preparation of trinuclear complex 3.
References
1. Kaizuka, K.; Miyamura H.; Kobayashi S. J. Am. Chem. Soc. 2010, 132, 15096–15098.
24. Ito, N. L.; Johnson, J. B.; Mueting, M. A.; Pignolet, H. L. Inorg. Chem. 1989, 28, 2026-2028.
25. Goto, E.; Begum, A. R.; Ueno, C.; Hosokawa, A.; Yamamoto, C.; Nakamae, K.; Kure, B.; Nakajima, T.; Kajiwara, T.;
Tanase, T. Organometallics 2014, 33, 1893-1904.
26. Yamada, T.; Mawatari, A.; Tanabe, M.; Osakada, K.; Tanase, T. Angew. Chem., Int. Ed. 2009, 48, 568-571.
27. Joost, M.; Estevez, L.; Mallet-Ladeira, S.; Miqueu, K.; Amgoune, A.; Bourissou, D. J. Am. Chem. Soc. 2014, 136, 10373-
10382.
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The 7th Asian Silicon Symposium
POSTER PRESENTATION ǀ Page 79
Preparation of Photosensitive Organosilicon Prepolymer and Its
Application in Photocuring 3D Printing
Qiu Chen
Key Laboratory of Organosilicon Chemistry and Material Technology, Hangzhou Normal University,
Hangzhou 311121, China
In recent years, People have higher and higher requirements for the quality of photocurable three-
dimensional printing products. At present, the main raw materials used in the three-dimensional
photocuring printing technology are epoxy resin and acrylic resin. Although these two types of resins
can meet the basic requirements for three-dimensional photocuring, they cannot meet the higher
requirements for three-dimensional printing due to problems such as large viscosity of the resin, large
volume shrinkage after curing, and poor toughness of molded products.
Photocured organic/inorganic hybrid polymers have the advantages of both organic and inorganic
materials. In this work, photocurable silica sol of organic-inorganic hybrid prepolymers were
synthesized from tetraethylorthosilicate (TEOS) and γ-methacryloxypropyltrimethoxysilane (KH570).
A synthetic silica sol was used as a photosensitive resin component to prepare a photosensitive resin
composition that can be used for three-dimensional rapid molding. The effect of different amounts of
silica sol prepolymer on the properties of the photosensitive resin composition was studied. The
experimental results show that the addition of synthetic silica sol prepolymer can play a role in
increasing the mechanical and thermodynamic properties, reducing volume shrinkage and also meet the
other requirements of the photocuring three-dimensional printing consumables.
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Nanyang Technological University
POSTER PRESENTATION ǀ Page 80
Complex on Silica Substrate
Joon Soo Han,a,* Song Yi Kim,a,b Jihee Choi,a,b
aMaterials Architecturing Research Center, Korea Institute of Science and Technology, Hwarangro 14-gil 5,
Seongbuk-gu, Seoul 02792, Republic of Korea bDept. of Chemistry, Graduate School of Science, Korea Univ. Anam-ro 145, Seongbuk-gu, Seoul 02841,
Republic of Korea
Eu3+ possess fascination optical properties such as large Stokes shifts, long lifetime, and unique line-
like emission in the red region.1 However, like other lanthanides, europium ion itself has weak
luminescence properties due to its low absorption coefficient. This problem can be overcome by
coordinating organic chromophore ligands such as β-diketonate, which are referred to as antennas or
sensitizers.
A variety of fluorescence-based devices have been reported using europium complexes as sensing
elements, and in many cases, silane coupling agents (SCAs) have been used to immobilize the europium
complex.2 However, systematic studies on the effects of SCA functional groups on the emission
properties of europium have been rarely conducted
Figure 1. Excitation (λem 613 nm) and emission (λex 345 nm) spectra of EuTTA(SCA)x solutions (5.6 µM in toluene). SCA/Eu3+
mole ratio = 2.0, except AEA/Eu3+ = 1.0. MPT: (3-mercaptopropyl)trimethxoysilane; APT: (3-aminopropyl) trimethoxysilane;
AEA: [3-(2-aminoethylamino)propyl]trimethoxysilane; DPPOSi: diphenyl[3-(trimethoxysilyl)propyl] phosphine oxide.
In this presentation, we will show results of grafting europium complex to silica-based substrates
such as glass, nano-silica, or SiO2 film, and discuss how SCA changes the luminescent properties of
europium complex.
References
1. Ma, Y.; Wang, Y. Coord. Chem. Rev. 2010, 254, 972–990.
2. Sanchez, C.; Belleville, P.; Popalld, M.; Nicol, L. Chem. Soc. Rev. 2011, 40, 696–753.
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The 7th Asian Silicon Symposium
POSTER PRESENTATION ǀ Page 81
Study on Damping Mechanism Based on the Free Volume for
Polysiloxanes by Molecular Dynamics Simulation and
Experiments
Lin Zhu,a ChuanJian Zhouab,*
aSchool of Materials Science and Engineering, Shandong University, Jinan 250061,China. bKey Laboratory of Special Functional Aggregated Materials, Ministry of Education,Jinan 250061, China
The influences of the free volume and the temperature on the damping property of
polydimethylsiloxane (PDMS), poly(dimethyl-co-methylphenylsiloxane)(PDMS-co-PMPS) and
poly(dimethyl-co-diphenylsiloxane)(PDMS-co-PDPS) were investigated by full-atom molecular
dynamics simulation (MD)[1], dynamic mechanical analysis (DMA), differential scanning calorimetry
(DSC) and linear thermal expansion[2], respectively. From the variations of free volume fraction (FFV)
as a function of temperature, glass transition temperatures can be observed. In order to clarify the
damping mechanics, the Williams-Landel-Ferry (WLF) equation based on free volume theory has been
successfully used to establish a direct quantificational relationship between the free volume and the
damping property[3], which indicates that the free volume plays an important role in determining the
damping property. These results provide a basis for the design and fabrication of high-performance
polysiloxanes.
Figure 1. FFV vs Linear thermal expansion of three polysiloxanes
Figure 2. Log10[tan δ(T)] versus relative fractional free volume (1 -frg/fr) for (a) PDMS, (b)PDMS-co-PMPS and
(c) PDMS-co-PDPS at 1, 10, and 100 Hz.
References
1. M. Huang, L.B. Tunnicliffe, A.G. Thomas, J.J.C. Busfield. Eur. Polym. J. 2015,67, 232–241.
2. Wu G, Nishida K, Takagi K, Sano H, Yui H..Polymer 2004,45,3085-3090.
3. Yuchan Z, Guangsu H.J. Phys. Chem. B 2007, 111, 11388-11392.
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Nanyang Technological University
POSTER PRESENTATION ǀ Page 82
Atmospheric Pressure Chemical Vapor Deposition on a Self-
assembled Silicone Coating
Yuta Goto,a Kohei Masuda,a Koichi Higuchi,a,* Graham Garner,b Susan Farhatb and Mary Gilliamb,*
a Shin-Etsu Chemical Co., Ltd., Silicone Electronics Materials Research Center, Gunma, Japan b Department of Chemical Engineering, Kettering University, Flint, MI USA
[email protected], [email protected]
A self-assembly is the autonomous organization of components into patterns or structures without
human intervention, whose processes are common throughout nature and technology. Several papers
about the concept of self-assembly in organosilicon compounds have been reported.1 We also have
reported a paper about the self-assembly silicone acrylate coating (Figure 1).2 Although our research
effort has been devoted to develop radiation-curable coating with high weather durability, we proposed
how to easily detect the structure of a self-assembled silicone coating and identified the factor for self-
assembly. It is essential to include both the silicone acrylate 3 and hexanediol diacrylate (HDDA) in the
coating formulation for self-assembly to occur. The acrylate 3 was prepared by transesterification of
silicate oligomer 1 with -functionalized acrylic alcohol 2 (Scheme 1). Outdoor weathering results of
the self-assembled silicone coatings are obtained after 1 year of testing in Florida and Arizona, which
showed better performance than the non-silicone or the uniform single-layer silicone coating systems.
It is possible that the unique structure of the coating protects the coating from UV- or water-induced
degradation. Moreover, atmospheric pressure chemical vapor deposition on the self-assembled silicone
coatings is being undertaken in our group,3 which is expected to improve durability against scratch and
abrasion and enhanced protection from exposure compared to the uniform single-layer silicone coatings.
The results will be presented in this poster session.
Figure 1. Self-assembly silicone acrylate coating
Scheme 1. Synthesis of silicone acrylate 3
References
1. Lu, Y.; Fan, H.; Doke, N.; Loy, D. A.; Assink R. A.; LaVan, D. A.; Brinker, C. J. J. Am. Chem. Soc. 2000, 122, 5258-
5261. b) Zhang, W.; Fang, B.; Walther, A.; Müller, A. H. E. Macromolecules 2009, 42, 2563-2569. c) Zheng, L.; Hong,
S.; Cardoen, G.; Burgaz, E.; Gido S. P.; Coughlin E. B. Macromolecules 2004, 37, 8606-8611.
2. Masuda, K.; Tsuchida, K.; Inoue, T.; Gilliam, M. Journal of Coatings Technology and Research 2019, 16, in print. (DOI:
https://doi.org/10.1007/s11998-018-00171-5)
3. Gilliam, M.; Farhat, S.; Higuchi, K.; Masuda, K.; Yoshii, R. International Application PCT/US2019/024223, 2019.
MeO Si O Me
OMe
OMe
ROH (2)(R = CH2CH2OCOCH=CH2)
transesterification
1
n
RO Si O R
OR
OR n3
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The 7th Asian Silicon Symposium
POSTER PRESENTATION ǀ Page 83
Preparation of robust Reverse Osmosis membranes for water
desalination Effects of co-polymerization with BTESPA on their
performance
Dian Zhang,a Joji Ohshita,a Feng-Tao Zheng,a Kazuki Yamamotob
aDepartment of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima
739-8527, Japan bPure and applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, Chiba 278-
8510, Japan
Water scarcity has been discussed as a global issue and the development of an efficient strategy for
water purification is needed. Reverse osmosis (RO) with a semipermeable membrane is widely used for
water desalination. Organically bridged polysilsesquioxanes can be used for RO membranes with high
thermal stability and chlorine resistance. According to our previous research, a rigid and polar bridged
structure can improve the porosity and hydrophilicity of the membranes, thus, we anticipate that co-
polymerization with polar and bridged structure can also improve water permeability. Another thing
that we anticipate is co-polymerization with a highly thermostable and chlorine resistance precursor
BTESE can improve the chemical stability of membranes.
In this work, to increase the resistance of chlorine and thermostability and improve RO performance
of membranes, we used two kinds of nitrogen-containing precursors BTESPA and BTESMAz for co-
polymerization with BTESE, the results show that the RO performance and robustness are improved
significantly.
Fig 1. Structures of BTESE, BTESPA and BTESMAz
References
1. M. Elimelech, W.A. Phillip, Science 2011, 333, 712.
28. Zheng, F.-T, Kazuki Yamamoto, Masakoto Kanezashi, 2018. 546: p. 173-178.
29. G. A. Tularam and M. Ilahee, J. Environ. Monit. 2007, 9, 805.
30. L. Weinrich, C. N. Haas, M. W. LeChevallier, J. Water Reuse Desal. 2013, 3, 85.
31. R. Xu, J. Wang, M. Kanezashi, T. Yoshioka, T. Tsuru, Langmuir 2011, 27, 13996.
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Nanyang Technological University
POSTER PRESENTATION ǀ Page 84
Hydride and p-Tolylsiloxanes Oxidation: Development of Catalytic
Approaches
Irina K. Goncharova, Ashot V. Arzumanyan, Aziz M. Muzafarov
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilova Street, Moscow
119991, Russian Federation
Organosilicone chemistry was the much slowlier developing field of chemistry compared to organic
chemistry. So, much methods for obtaining [Si]-derivatives, functionalized ones, in particular, still are
time-consuming, require harsh conditions, stoichiometric amounts of toxic and expensive reagents
producing waste (some of them are commercially unavailable) which provokes Si–O-, Si–C- and other
bonds destruction. Sometimes these methods are of low functional group tolerance.1
On the other side, functionalized siloxanes are believed will widen the fields of applicability of such
compounds. So, developing of “green” and commercially available systems for functionalization of
siloxanes is an actual task. Green chemistry, is thought, will became the only suitable appproach for
selective synthesis of siloxanes with complex structures.
Two target types of compounds were chosen for elaboration of suitable method: siloxanols and p-
carboxyphenylsiloxanes. Both they can be obtained via oxidation of easily accesible hydride siloxanes
and p-tolylsiloxanes.
Well proven peroxide and metal combination was the first system to be tried for these oxidtions
(Scheme 1, route A).2,3 After optimizing the conditions we concluded, that this system allows simple
compounds to be oxidixed with high conversions (such as triethylsilane and p-
tolylpentamethyldisiloxane), but requires more harsh conditions for more complex ones.
Then O2 was chosen as an oxidant in combination with transition metal and organic catalyst. After
optimizing the conditions we found out that this approach is applicable for both hydride and p-
tolylsiloxanes of varios structures oxidation in good conversions and yields (Scheme 1, route B).4,5
References
1. Abakumov, G. A.; Piskunov, A. V.; Cherkasov, V. K. et al. Russ. Chem. Rev. 2018, 87 (5), 393−507.
2. Arzumanyan, A. V.*; Goncharova, I. K.; Novikov, R. A. et. al. Synlett. 2018, 29 (4), 489−492.
3. Goncharova, I. K.; Arzumanyan, A. V.*; Milenin, S.A.; et. al. J.Organomet. Chem. 2018, 862, 28−30.
4. Arzumanyan, A. V.*; Goncharova, I. K.; Novikov, R. A. et.al. Green Chem. 2018, 20 (7), 1467−1471.
5. Goncharova, I. K.; Silaeva, K.P.; Arzumanyan, A.V.* et.al. J. Am. Chem. Soc. 2019, 141 (5), 2143-2151.
This work was supported by the Grant of the Government of the Russian Federation No. 14.W03.31.0018.
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The 7th Asian Silicon Symposium
POSTER PRESENTATION ǀ Page 85
Chemical Bonding Information on Ylidene-substituted Silanes
from Experimental Electron Density Distribution
Alfredo Rosas-Sánchez,a,* Tsuyoshi Kato,b Daisuke Hashizumea
aRIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan bUniversité de Toulouse, UPS, and CNRS, LHFA UMR 5069, 31062 Toulouse, France
Phosphoranylidenes, R3P=YRn’, have proved to act as good electron donor substituents towards
low-valent species such as carbenes and silylenes.1 Recently, we reported the development of a novel
boron-based phosphoranylidene (borylidene phosphorane, R3P=BR’) which shows an exceptionally
strong π-electron donating character, compared to its carbon analogue phosphonium ylide.2 Indeed, the
N-heterocyclic silylene (NHSi) substituted by the borylidene phosphorane presents considerably
increased stability and nucleophilic character.3 To gain deeper insight into the nature and the electron
donating ability of the newly discovered borylidene phosphorane, we have performed experimental
Electron Density Distribution (EDD) analyses on cyclic amino (dihalo) silanes bearing the borylidene
(1) and carboylidene (2) moieties (Figure 1, top), and examined the chemical bonding by means of
Source Function (SF) contributions at bond critical points (BCPs). Analysis of the SF at BCPB-Si in 1
and BCPC-Si in 2 (Figure 1a and b, bottom) revealed both ylidene moieties acting as electron donors
towards the tetracoordinated silicon atoms. However, SF at BCPs associated to the interactions of NHC
and phosphorane groups with boron in 1, showed that both substituents contribute to increase the
electron density in the borylidene moiety, contrary to the imino and phosphorane substituents in 2,
which act as electron withdrawing groups for the carboylidene moiety.
Figure1.top: Structures of cyclic amino(dihalo)silanes bearingendocyclic borylidene 1andendocyclic carboylidene 2. bottom:
SF contribution of atomic basins at a) BCPB-Siin 1; b) BCPC-Siin 2.
References
1. a) Kobayashi, J.; Nakafuji, S.; Yatabe, A; Kawashima, T. Chem. Commun. 2008, 6233–6235. b) Karni, M.; Apeloig, Y.
Organometallics 2012, 31, 2403−2415 and references cited therein.
2. Rosas-Sánchez, A.; Alvarado-Beltran, I.; Baceiredo, A.; Hashizume, D.; Saffon-Merceron, N.; Branchadell, V.; Kato, T.
Angew. Chem. Int. Ed. 2017, 56, 4814 –4818.
3. Rosas-Sánchez, A.; Alvarado-Beltran, I.; Baceiredo, A.; Saffon-Merceron, N.; Massou, S.; Branchadell, V.; Kato, T.
Angew. Chem. Int. Ed. 2017, 56, 10549 –10554.
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Nanyang Technological University
POSTER PRESENTATION ǀ Page 86
Synthesis and Property of Doubly Bonded Rhodium-Silylene
Complex
Shintaro Takahashi, Norio Nakata*, Akihiko Ishii
Department of Chemistry, Graduate School of Science and Engineering, Saitama University, Shimo-okubo,
Sakura-ku, Saitama-city, Saitama, 338-8570, JAPAN.
Transition metal-silylene complexes have been widely investigated as important intermediates in
catalytic reactions of organosilicon compounds such as hydrosilylation, dehydrocoupling, and so on.
Since two Lewis base-stabilized metal-silylene complexes were independently reported in 1987,1 the
coordination chemistry of silylene toward trantision metal complexes have been developed dramatically
until now.2 In particular, amidinato silylenes have drawn much attention due to their strong coordination
ability toward transition metal complexes. Meanwhile, we recently succeeded in the synthesis and
characterization of iminophosphonamido chlorosilylene 1 that has higher nucleophilicity and stronger
σ-donor ability than the corresponding amidinate analogue.3 Herein we present the synthesis and
property of a novel rhodium-silylene complex having a distinct double bond character.
Mono coordinated Rhodium-silylene complex 2 was obtained by the reaction of [RhCl(cod)]2 with
2 molar equivalents of 1. Interestingly, the reaction of [RhCl(cod)]2 with 6 molar equivalents of 1
resulted in the formation of cationic rhodium-silylene complex 3. X-ray crystallographic analysis of 3
revealed that the middle Si–Rh bond [2.133(1)Å] is shorter than the other two Si–Rh bonds [2.342(1),
2.332(1)]Å and approximately 8% shorter than typical Si–Rh single bonds, indicating a double-bond
character between silicon and rhodium atoms. We also discuss further details for the bond nature in 3
from the viewpoints of experimental results and theoretical calculations.
Figure1. Iminophosphonamido silylene and theirrhodium complexes
References
1. a) Zybill, C.; Muller, G. Angew. Chem. Int. Ed. 1987, 26, 669−670. b) Straus, D. A.; Tilley, T. D.; Rheingold, A. L.; Geib,
S. J. J. Am. Chem. Soc 1987, 109, 5872−5873.
2. Álvarez-Rodríguez, L.; Cabeza, J. A.; Garcia-Alvarez, P.; Polo, D. Coord. Chem. Rev. 2015, 300, 1−28. 3. So, C.-W.; Roesky, H. W.; Magull, J.; Oswald, R. B. Angew.Chem. Int. Ed. 2006, 118, 3948−3949.
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The 7th Asian Silicon Symposium
POSTER PRESENTATION ǀ Page 87
π-Conjugated Ditetrene Compounds with Thiophene Rings
Shogo Yagura,a Ryoma Ohno,a Shogo Nishimura,a Naoki Hayakawa,a Daisuke Hashizume,b Tsukasa Matsuoa,*
aDepartment of Applied Chemistry, Faculty of Science and Engineering, Kindai University,
3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502, JAPAN bRIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama 351-0198, JAPAN
[email protected], [email protected]
We have studied a varietyof π-electron systems containing a Si=Si double bond stabilized by the
fused-ring bulky Rind groups (Rind = 1,1,3,3,5,5,7,7-octa-R-substituted s-hydrindacen-4-ly).1
Previously, we reported the synthesis and photophysical properties of a series of 1,2-diaryldisilenes,
(Eind)ArSi=SiAr(Eind) (Eind = 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl).2,3 The 1,2-dinaphthyl-
disilenes are air-stable in the solid state and exhibitan intense emission at room temperature.2
Here we report the synthesis and characterization of the thienyl-and bithienyl-substituted disilenes
supported by the bulky Eind groups.4 The photophysical properties and theoretical calculations provide
clear evidence for the effective π-conjugation between the Si=Si double bond and thiophene units. We
also present the π-conjugated digermene compound, 1,2-dithienyldigermene, bearing the bulky Eind
groups, which can be obtained by the reaction of the 1,2-dibromodigermene, (Eind)BrGe=GeBr(Eind),5
with 2-thienyllithium.
References
1. T. Matsuo, N. Hayakawa, Science and Technology of Advanced Materials (STAM) 2018, 19, 108–129. 2. a) M. Kobayashi, N. Hayakawa, K. Nakabayashi, T. Matsuo, D. Hashizume, H. Fueno, K. Tanaka, K. Tamao, Chem. Lett.
2014, 43, 432–434. b) T. Matsuo, M. Kobayashi, K. Tamao, Dalton Trans. 2010, 39, 9203–9208. c) M. Kobayashi, T.
Matsuo, T. Fukunaga, D. Hashizume, H. Fueno, K. Tanaka, K. Tamao, J. Am. Chem. Soc. 2010, 132, 15162–15163. 3. M. Kobayashi, N. Hayakawa, T. Matsuo, B. Li, T. Fukunaga, D. Hashizume, H. Fueno, K. Tanaka, K. Tamao, J. Am.
Chem. Soc. 2016, 138, 758–761. 4. N. Hayakawa, S. Nishimura, N. Kazusa, N. Shintani, T. Nakahodo, H. Fujihara, M. Hoshino, D. Hashizume, T. Matsuo,
Organometallics 2017, 36, 3226–3233. 5. N. Hayakawa, T. Sugahara, Y. Numata, H. Kawaai, K. Yamatani, S. Nishimura, S. Goda, Y. Suzuki, T. Tanikawa, H.
Nakai, D. Hashizume, T. Sasamori, N. Tokitoh, T. Matsuo, Dalton Trans. 2018, 47, 814–822.
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