Book of Abstractsichf.edu.pl/ml2013/EN/files/ML2013_BoA.pdfMolecules and Light 2013, Zakopane 23-27...

Molecules and Light 2013 II Autumn Meeting of the Polish Photochemistry Grou p

Zakopane, 23-27 September 2013

Book of Abstracts

Institute of Physical Chemistry PAS, Warsaw

Jagiellonian University, Kraków Institute of Physics PAS, Warsaw

Adam Mickiewicz University, Pozna ń

http://ichf.edu.pl/ml2013

Molecules and Light 2013, Zakopane 23-27 September 2013

Official conference web site: http://ichf.edu.pl/ml2013

Important Information Conference venue: Hotel Pod Berłami , Zakopane, ul. Grunwaldzka 9 Tel./fax: +48 18 20 132 21, www.podberlami.com (all lectures, communications, panel discussion and

poster session)

Welcome Dinner: Hotel Carlton , Zakopane, ul. Grunwaldzka 11 (23 Sept. 2013) Tel.: +48 18 20 144 15, www.carlton.pl

Conference Dinner: Karczma Czarci Jar , Zakopane, ul. Małe śywczańskie 11a

(25 Sept. 2013) Tel./fax: +48 18 20 641 78, www.czarcijar.pl Edition: Jerzy Karpiuk Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw Jagiellonian University, Kraków Institute of Physics, Polish Academy of Sciences, Warsaw Adam Mickiewicz University, Poznań

All rights reserved.


Organizing Committee

Conference Chairmen Jerzy Karpiuk (Institute of Physical Chemistry PAS, Warsaw)

Marek Mac (Faculty of Chemistry, Jagiellonian University, Cracow)

Members Marek Sikorski (Faculty of Chemistry, Adam Mickiewicz University, Poznań)

Bolesław Kozankiewicz (Institute of Physics PAS, Warsaw)

Edyta Deluga (Institute of Physical Chemistry PAS, Warsaw)

Alina Majka (Institute of Physical Chemistry PAS, Warsaw)

Michał Pacia (Faculty of Chemistry, Jagiellonian University, Kraków)

Karolina Woyciechowska (Faculty of Chemistry, Jagiellonian University, Kraków)

Sponsors and exhibitors The ML2013 Meeting is sponsored by the Leading National Research Centre KNOW (Krajowy Naukowy Ośrodek Wiodący KNOW)

Exhibitors COMEF Aparatura Naukowo-Badawcza, Katowice

EUROTEK International, Warsaw

Gilden-Photonics, Cyldebank

Princeton Instruments, New Jersey

Scitec Instruments Polska, Warsaw

Table of Contents


Table of Contents

Important Information ............................. ............................ 2

Organizing Committee .............................. .......................... 3

Exhibitors ......................................... ................................... 3

Welcome ........................................... ................................... 5

Conference Program.................................. ......................... 6

Plenary Lectures ................................... ............................ 12

Invited Lectures .................................. .............................. 20

Panel Discussion ................................... ........................... 26

Oral Communications ............................... ........................ 30

Exhibitor presentations ............................ ........................ 48

Posters............................................. .................................. 50

Welcome


Welcome Dear colleagues and friends, Two years after our first Autumn Meeting of the Polish Photochemistry Group we have again the honour and pleasure to welcome you in Zakopane to attend the Molecules and Light 2013 Conference.

Following a very positive response to ML2011, this year's edition is organised in a similar fashion and aims at reviewing current research conducted in Po-land in the field of photochemistry and photophysics, and at providing oppor-tunity for establishing and strengthening scientific and personal contacts be-tween the members of our community. We organise the meeting under the auspices of the European Photochemistry Association, as the Polish Section of the EPA, as we feel it is an excellent platform to combine national review of our field with an international perspective.

We are happy that many participants of ML2013 are young researchers, post-docs, and PhD and undergraduate students. We hope that your more experi-enced colleagues will give you incentives and inspiration in your quest for your place in science. This is also one of the reasons why we would like to thank all those who have kindly accepted the invitation and come to Zakopane to deliv-er a lecture. The onset of the autumn, here in Poland called the golden Polish autumn due to beautiful colours of Nature, is an especially suitable time to look for stimulation and inspiration with new concepts and ideas on molecules and light. We wish you many positive excitements and breaking new ground during ML2013.

The present meeting is a joint effort of four institutions: two institutes of the Polish Academy of Sciences, the Institute of Physical Chemistry and the Insti-tute of Physics, the Jagiellonian University and the Adam Mickiewicz Universi-ty, and we sincerely acknowledge their financial support. We thank also our exhibitors and sponsors for their contributions.

We wish you stimulating, inspiring and fruitful meeting. We also hope that you will enjoy numerous attractions of the capital of Polish Tatra Mountains. Jerzy Karpiuk, Marek Mac, Bolesław Kozankiewicz, Marek Sikorski

23 September 2013, Zakopane

Conference Program


Conference Program Monday, 23 September, 2013

Monday, 23 September, 2013:

14.00-19.00 Registration

Monday, 23 September 2013 Evening Session: 19.00-23.00

Light and molecules in action Opening Session

19.00-19.15 Welcome addresses 19.15-20.15 Opening lecture

Andrzej Sobolewski, Institute of Physics, Polish Academy of Sciences, Warsaw

Juggling with protons: molecules and light in action

20.15-23.00 Welcome dinner

Tuesday, 24 September 2013

Tuesday, 24 September 2013 Morning Session: 9.00-13.15

Ultrafast Spectroscopy

9.00-10.00 PL1

Eberhard Riedle , Faculty of Physics, Ludwig-Maximilian-University of Munich

Photochemistry across time and spectral domains: The generation and reactions of benzhydryl cations

10.00-10.45 IL1

Gotard Burdzi ński , Faculty of Physics, Adam Mickiewicz University, Poznań

Importance of bleaching bands in ultrafast UV-Vis and mid-IR transient absorp-tion studies

10.45-11.15 Coffee break

11.15-12.00 IL2

Marcin Ziółek , Faculty of Physics, Adam Mickiewicz University, Poznań

Ultrafast studies of charge transfer processes in dye-sensitized solar cells 12.00-12.30

OC1 Bernhard Lang, Institute of Physical Chemistry, University of Geneva

Broadband UV-VIS transient absorption spectroscopy in the nanosecond to microsecond time domain with sub-ns time resolution

12.30-13.00 OC2

Jerzy Karpiuk, Institute of Physical Chemistry, Polish Academy of Science, Warsaw Ultrafast excited-state dynamics of spirocyclic bichromophoric D–A systems

13.00-13.15 Theodor Herrmann , Princeton Instruments, New Jersey Exhibitor presentation

Conference Program


Tuesday, 24 September 2013 Afternoon Session: 14.30-18.25

Photons and fluorescence - methods and applications

14.30-15.30 PL2

Sebastiano Campagna , Department of Chemical Sciences, University of Messina

A molecular approach to artificial photosynthesis 15.30-16.15

IL3 Konrad Szaciłowski , AGH University of Science and Technology, Kraków

Processing information with light and molecules 16.15-16.25

OC3 Agnieszka Podborska, Faculty of Chemistry, Jagiellonian University, Kraków Molecular logic devices based on photosensitized TiO2


16.55-17.40 OC4

John Gilchrist , Gilden Photonics Ltd., Clydebank

Fluorescence spectroscopy: the journey of the photon, and what is important for measuring corrected spectra

17.40-18.10 OC5

Marek Sikorski, Faculty of Chemistry, Adam Mickiewicz University, Poznań Synchronous Fluorescence Spectroscopy: Methods and Applications

18.10-18.25 C2

John Gilchrist , Gilden Photonics Ltd., Clydebank Exhibitor presentation

Tuesday, 24 September 2013 Evening Session: 20.00-21.30

Poster session

Wednesday, 25 September 2013

Wednesday, 25 September 2013 Morning Session: 9.00-13.20

Energy transfer and plasmonics

9.00-10.00 PL3

Werner Nau , School of Engineering and Science, Jacobs University, Bremen

Collision-induced quenching, FRET, and diffusion-enhanced FRET in peptidic biopolymers

10.00-10.30 OC6

Jacek Waluk , Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw Tautomerism in porphycenes: new findings

10.30-10.50 OC7

Jędrzej Solarski, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw

Dexter-type energy transfer in liquid solution. A new approach to kinetic description


11.20-12.05 IL4

Wojciech Macyk , Faculty of Chemistry, Jagiellonian University, Kraków

Singlet oxygen generation in titanium dioxide colloids. The effect of NIR irradiation 12.05-12.25

OC8 Marek Oszajca, Faculty of Chemistry, Jagiellonian University, Kraków

Photoluminescence enhancement of CdSe and CdSe-ZnS nano-crystals by on-surface ligand modification

12.25-12.45 OC9

Dorota Kowalska, Institute of Physics, Nicolaus Copernicus University, Toruń

Plasmon – fluorophore interactions between cyanobacterial Photosystem I and Silver Island Film

Conference Program


12.45-13.05 OC10

Maria Olejnik, Institute of Physics, Nicolaus Copernicus University, Toruń

Florescence microscopy as a suitable technique for studying plasmon- emitter interactions

13.05-13.20 C3

Artur Gazewski , Comef Aparatura Naukowo-Badawcza, Katowice Exhibitor presentation

Wednesday, 25 September 2013, 14.30 – 19.00: Excursion

Wednesday, 25 September 2013 Evening, 20.00 – 24.00

Conference Dinner

Thursday, 26 September 2013

Thursday, 26 September 2013 Morning Session: 9.00-13.15

Solvation, electron transfer and single molecules

9.00-10.00 PL4

Mark Maroncelli , Department of Chemistry, The Pennsylvania State University, Univer-sity Park

Solvation and Solvation Dynamics in Ionic Liquids 10.00-10.30

OC11 Jacek Dobkowski, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw

TICT - the most controversial excited state of the last 50 years: The case of cyanopyridine derivatives.

10.30-10.45 C4

Józef Dresner , Eurotek International, Warsaw Exhibitor presentation


11.15-12.15 PL5

Jan Najbar , Faculty of Chemistry, Jagiellonian University, Kraków

Time-dependent rate coefficients for electron transfer reaction 12.15-12.45

OC12 Gonzalo Angulo, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw

Photo-induced formation and recombination of ions in bimolecular reactions in solution: a never ending story

12.45-13.15 OC13

Bolesław Kozankie wicz, Institute of Physics, Polish Academy of Sciences, Warsaw

Triplet states in optical studies of single molecules

Thursday, 26 September 2013 Panel Discussion: 15.00-18.30

Solvation dynamics

15.00-16.30 PD

Part 1: Introduction: Jerzy Karpiuk Contributions: Mark Maroncelli, Eberhard Riedle


17.00-18.30 Part 2: Open discussion: short spontaneous contribut ions are welcome

Conference Program


Friday, 27 September 2013

Friday, 27 September 2013 Morning Session: 9.00-12.45

Theory and solid state photoluminescence

9.00-10.00 PL6

Regina de Vivie -Riedle , Department of Chemistry, Ludwig-Maximilian-University of Munich

Molecular features in complex environment: cooperative team players during excited state bond cleavage

10.00-10.45 IL5

Sylwia F reza, Department of Chemistry, University of Gdańsk

Spotlight on dipole-bound anions 10.45-11.05

OC14 Joanna Jankowska , Warsaw University, Warsaw

Salicylidene methylamine and its derivatives – the photophysics of model Schiff bases


11.30-11.50 OC15

Przemysław Kwolek , AGH University of Science and Technology, Kraków

Photoluminescence properties of BixLa1-xVO4 solid solutions 11.50-12.10

OC16 Justyna Mech , AGH University of Science and Technology, Kraków

Photoelectrochemical properties of BiVO4 12.10-12.30

OC17 Kacper Pilarczyk , AGH University of Science and Technology, Kraków Synthesis and properties of antimony sulphide quantum dots

12.30-12.45 Closing remarks

List of Posters


Posters:

P1 Małgorzata Borowiak , Institute of Experimental Physics, University of Gdańsk

Spectroscopic studies of selected flavonoids in various environments P2 Joannna Buczy ńska , Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw

Complicated photophysics of anils and boranils P3 Edyta Deluga , Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw

Dual fluorescence of a hydrazide analogue of crystal violet lactone – a solvent effect study P4 Mateusz Gierszewski , Faculty of Chemistry, Adam Mickiewicz University, Poznań

Excited-state double proton transfer in 5-deazaalloxazines P5 Michał Gil , Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw

Structural distortion and state inversion effects in the 1,4-diazatriphenylene cooled in supersonic jets

P6 Barbara Golec , Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw Solvent-induced changes in photostability of 2-(1H-indole-2-yl)-[1,5]naphthyridine

P7 Alina Krawczyk , Faculty of Chemistry, Adam Mickiewicz University, Poznań The usefulness of spectroscopic methods for assessing color stability of dental materi-als

P8 Kornelia Lewandowska , AGH University of Science and Technology, Kraków Study of electronic properties of fullerene-thiophene dyads

P9 Marek Mac , Tomasz Uchacz, Faculty of Chemistry, Jagiellonian University, Kraków Applications of fluorescent sensor based on 1H-pyrazolo[3,4-b]quinoline in analytical chemistry

P10 Alina Majka , Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw Solvent effect on dual fluorescence of bridged triarylmethane lactones

P11 Marzena Marchaj , Piotr Skurski, Department of Chemistry, University of Gdańsk Chemically oxidized water

P12 Natalia Masiera , Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw Photophysical properties of selected porphycene derivatives substituted at meso posi-tions with phenyl groups

P13 Gabriela Mazur , Faculty of Chemistry, Jagiellonian University, Kraków Stability of platinum and palladium complexes with cyano- and imidazolylcobalamin

P14 Justyna Mech , AGH University of Science and Technology, Kraków Photoelectrochemical properties of BiVO4

P15 Olaf Morawski , Institute of Physics, Polish Academy of Sciences, Warsaw Photochemistry of methylene blue in water

P16 Michał Pacia , Faculty of Chemistry, Jagiellonian University, Kraków Stability and photocatalytic activity of titanium dioxide colloids stabilized with polymers

P17 Joanna Piechowska , Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw Synthesis and photoinduced electron transfer in bridged diarylmethane lactones

List of Posters


P18 Dorota Prukała , Faculty of Chemistry, Adam Mickiewicz University, Poznań

Influence of pH and solvents polarities on photophysical properties of N-(4-bromobenzyl) substituted hydroxystilbazolium hemi- and merocyanine

P19 Michał Rode, Institute of Physics, Polish Academy of Sciences, Warsaw Theoretical study on photophysics of PT-based molecular photo-switches

P20 Jacek Wierzchowski , University of Warmia & Mazury, Olsztyn Excited-state proton transfer in nucleobase and nucleoside analogs: an update

P21 Gabriela Wiosna -Sałyga , Technical University of Łódź, Łódź New benzotriazole based polymers as potential active materials in organic light emitting devices

P22 Marek Wojnicki , AGH University of Science and Technology, Kraków Oscillation of gold(III) complex chloride ions concentration during photoreduction with methanol: kinetic study

P23 Karolina Woyciechowska , Faculty of Chemistry, Jagiellonian University, Kraków Investigations on the photoactivity of the Au@TiO2

Plenary Lectures


Plenary Lectures

Opening Lecture


Juggling with protons: molecules and light in actio n

Sobolewski A. L.

Institute of Physics, Polish Academy of Sciences, 02-668 Warsaw, Poland, [email protected]

Proton is the lightest nuclei and its monatomic form (H1) is the most abundant chemical sub-stance, constituting roughly 75% of the Universe's baryonic mass. The relative lightness and small size of this “quantum” particle explains the unusually high diffusion rate of the ‘excess’ proton through the hydrogen bond network of water molecules – the Grotthuss mechanism. When covalently bound to a molecule, it can relatively easily jump between so-called proton donating/accepting spots of a molecular frame resulting in formation of manifold of its tautomer-ic forms. A question of control of its motion with the aid of light fields is not only of fundamental interest, but may also results in some practical applications.

Optically induced excited state intra- and inter-molecular proton transfer (ESPT) has proven itself to be one of the most rapid events in chemistry with its rate sometimes rising to that of molecular X-H stretching vibrations (~1015s-1). From the fundamental point of view, is now wide-ly agreed that many phenomena designated as ESPT are not well described as proton transfer at all, but rather as strongly proton coupled electron transfer (PCET), i.e. hydrogen atom trans-fer. Applications of the phenomenon range from lasers and light-emitting diodes through poly-mer photostabilization to CO2-fixing photosynthetic reactions in green plants and bacteria and construction of artificial photosynthetic systems.

Plenary Lectures


Fig.1 Processes in the photolysis of benzhydryl-chloride.

The generation and reaction of benzhydryl cations:

a complex and multi-step process over many time ran ges investi-gated by transient spectroscopy from the deep UV to the NIR

Riedle E., Wilcken R., Sailer C. F.

LS für BioMolekulare Optik, LMU München, [email protected]

Benzhydryl radicals and cations are reactive intermediates central to the understanding of

organic reactivity. They can be generated from benzhydryl halides by UV irradiation. We per-formed transient absorption measurements over the range from femtoseconds to micro-seconds to unravel the complete reaction scheme. Our extremely wide probe range [1,2] allows the unambiguous monitoring of all fragments [3]. The appearance of the radical is delayed to the opti-cal excitation, the onset of the cation signal is found even later. According to ab-initio calculations we assign this non-rate behavior in the 100 fs range to wavepacket motion from the Franck-Condon region to two distinct conical intersections. The rise of the

optical signal with a quasi-exponential time of 300 fs is assigned to the planarization and solva-tion of the photoproducts [4]. The bond cleavage predominantly generates radical pairs. A sub-sequent electron transfer transforms radical pairs into ion pairs. Due to the broad inter-radical distance distribution and the distance dependence the electron transfer is strongly non-exponential. Part of the ion pairs recombine geminately. The electron transfer and the recombi-nation are terminated by the depletion of close pairs and diffusional separation. The remaining free radicals and cations undergo further reactions in the ns to µs regime.

In my talk I will briefly review our recent developments of the transient spectrometers that al-low measurements with fully tunable excitation, a time range from few fs to sub-ms and a probe coverage of 225 – 1700 nm. As central topic for the demonstration of the capabilities and the new methods developed to evaluate the raw data, I will use the case study of the photolysis of benzhydryl-halides.

[1] U. Megerle, I. Pugliesi, C. Schriever, C. F. Sailer, E. Riedle, Appl. Phys. B 96, 215 (2009) [2] E. Riedle, M. Bradler, M. Wenninger, C. F. Sailer, I. Pugliesi, Faraday Disc.,

DOI:10.1039/C3FD00010A (2013) [3] C. F. Sailer, B. P. Fingerhut, S. Thallmair, C. Nolte, J. Ammer, H. Mayr, I. Pugliesi, R. de Vivie-

Riedle, E. Riedle, ChemPhysChem 14, 1423 (2013) [4] B. P. Fingerhut, C. F. Sailer, J. Ammer, E. Riedle, R. de Vivie-Riedle, J.Phys.Chem. A 116, 11064

(2012)

Plenary Lectures


A molecular approach to artificial photosynthesis

Campagna S.

Dipartimento di Scienze Chimiche and Centro Interuniversitario per la Conversione Chimica dell'Energia Solare (SOLAR-CHEM), Università di Messina, Via Sperone 31, 98166 Messina,

Italy. Email: [email protected]

Conversion of solar energy into fuels (artificial photosyntesis) is one of the Holy Grail of Science. Solution of this complex problem is quite appealing, as it could alleviate the huge energy problems which our society is going to face.

Artificial photosynthesis, according to a bio-mimetic approach, requires the design of several components, each of them a supramolecular system, structurally organized and functionally integrated. Here we present some examples related to the design of: (i) light-harvesting antenna systems (their role: absorbing light and converting it into electronic energy, which can be funnel-led to specific sites of the assemblies); (ii) charge separation systems (role: to use the electronic energy collected by the antennae to perform charge separation, that is to transform electronic energy into redox energy); (iii) multielectron transfer catalysts (role: to accumulate the redox equivalents produced by the charge separation systems and perform the multi-electron transfer reactions required to obtain high-energy chemicals, e.g. fuels). As the key bottleneck for artifi-cial photosynthesis appears to be water oxidation, the examples reported for point (iii) will deal with water oxidation catalysts.

Moreover, emerging guidelines for the design of multicomponent systems capable of gene-rating long-lived photoinduced charge separation in donor-spacer-acceptor systems will be proposed.

Selected References [1] V. Balzani, S. Campagna, G. Denti, A. Juris, S. Serroni, M. Venturi, Acc. Chem. Res. 31, 26 (1998)

[2] J. Larsen, F. Puntoriero, T. Pascher, N. McClenaghan, S. Campagna, E. Åkesson, V. Sundström, ChemPhysChem 8, 2643 (2007)

[3] F. Puntoriero, G. La Ganga, A. Sartorel, M. Carraro, G. Scorrano, M. Bonchio, S. Campagna, Chem. Commun., 46, 4725 (2010)

[4] A. Sartorel, M. Bonchio, S. Campagna, F. Scandola, Chem Soc. Rev. 42, 2262 (2013)

Plenary Lectures


Collision-induced quenching, FRET, and diffusion-en hanced FRET

in peptidic biopolymers

Nau W. M.

School of Engineering and Science, Jacobs University Bremen, [email protected]

The structural and dynamic properties of the flexible peptidic polymer predetermine its bio-logical function, for example that of antibiotic or cell-penetrating polypeptides. These properties are imprinted in intrachain site-to-site distances as well as in diffusion coefficients of mutual site-to-site motion [1]. Information on the diffusional properties can be obtained by intrachain colli-sion-induced quenching experiments [2]. Both, distance distribution and diffusion, determine the extent of Förster resonance energy transfer (FRET) between two chain sites labeled by a FRET donor and acceptor fluorophore. Both can potentially be recovered from time-resolved FRET measurements with the precondition that their individual contributions to FRET efficiency can be experimentally varied.

Fig.1 Schematic illustration showing a donor-excited biopolymer, donor emission (top), donor quenching

(bottom), and FRET facilitated by diffusional motion (middle).

Because the diffusion enhancement of FRET depends on the donor-fluorescence lifetime, it was suggested to reduce the lifetime and so diffusion enhancement by adding an external quencher of donor fluorescence to the measurement solutions. It was then taken for granted that the equilibrium distance distribution becomes the dominant source of FRET efficiency [3]. Benefitting from the high diffusion sensitivity of short-distance FRET [4, 5], we tested this intri-guing idea on a (Gly-Ser)6 segment labeled at its termini by the donor–acceptor pair Naphtylal-anine (NAla) and Dbo. We found – to our surprise – that addition of the very effective donor-fluorescence quencher potassium iodide (KI) had not the slightest effect on diffusion enhance-ment although the fluorescence lifetime of the donor was shortened from 36 ns in absence of KI to 3 ns in presence of 30 mM KI. We think we now understand and recently published why the idea was meant to fail [6]. [1] E. Haas, E., E. Katchalski-Katzir., I.Z. Steinberg, Biopolymers, 17, 11 (1978). [2] F. Huang, R. R. Hudgins, W. M. Nau, J. Am. Chem. Soc., 126, 16665 (2004). [3] J.R. Lakowicz et al., J. Phys. Chem., 370, 385 (1991). [4] H. Sahoo, D. Roccatano, A. Hennig, W. M. Nau, J. Am. Chem. Soc., 129, 9762 (2007). [5] M. H. Jacob, W. M.Nau, In Folding, Misfolding and Nonfolding of Peptides and Small Proteins, (Wiley, Weinheim, 2011). [6] M. H. Jacob, R. N. Dsouza, I. Ghosh, A. Norouzy, T. Schwarzlose, W. M. Nau, J. Phys. Chem. B, 117, 185 (2013).

Plenary Lectures


Solvation and Solvation Dynamics in Ionic Liquids

Mark Maroncelli

Department of Chemistry, The Pennsylvania State University, [email protected]

Ionic liquids are a relatively new and rapidly expanding class of materials that are composed entirely of ions selected to remain fluid at or near to ambient temperatures. Research into both the fundamental properties and potential applications of these new materials has been quite vigorous over the past decade. Our main contribution to this field has been to characterize solvation dynamics in these liquids and understand the similarities and differences between solvation in ionic liquids compared to conventional dipolar solvents.

We have recently completed benchmark measurements of the complete (fs-ns) solvation re-sponse to the probe coumarin 153 in a representative collection of 21 ionic liquids.[1,2] These results confirm the presence of significant inertial dynamics taking place on the sub-picosecond time scale together with a broadly distributed structural component acting over the range 1 ps – 10 ns. Comparison to emerging dielectric measurements allow for definitive tests of dielectric continuum models of solvation. It is clear from these tests that solvation and dielectric relaxa-tion involve closely related molecular dynamics, but the connection offered by simple continuum models underestimates solvation times by factors of at least 2-4. Simple continuum models also suggest that integral solvation times should be inversely proportional to the static conduc-tivity of an ionic liquid.[3,4] Experimental data on 34 ionic liquids confirms the strong correlation between solvation times and inverse conductivity, albeit with a proportionality constant different by a factor of 2.4 from the continuum model prediction.[4] Computer simulations [1,5] provide insight into the relationship between solvation and dielectric response as well as mechanistic insights into the ion motions responsible for solvation. Whereas the sub-picosecond inertial dynamics entail easy-to-characterize translational motions of nearby ions, the structural relaxa-tion responsible for the ps-ns dynamics is quite subtle, involving small amplitude motions of ions imperceptibly different from random molecular motion. [1] M. Maroncelli, X.-X. Zhang, M. Liang, D. Roy, and N. P. Ernsting, Faraday Discuss. 154,

409 (2012). [2] X.-X. Zhang, M. Liang, N. P. Ernsting, and M. Maroncelli, J. Phys. Chem. B, DOI:

10.1021/jp305430a. [3] X.-X. Zhang, C. Schröder, and N. P. Ernsting, J. Chem. Phys. 138, 111102 (2013). [4] X.-X. Zhang, M. Liang, N. P. Ernsting, and M. Maroncelli, J. Phys. Chem. Lett. 4, 1205

(2013). [5] D. Roy and M. Maroncelli, J. Phys. Chem. B 116, 5951 (2012).

Plenary Lectures


The time dependent rate coefficients for electron t ransfer reaction

Marek Mac and Jan Najbar

Department of Physical Chemistry and electrochemistry, Faculty of Chemistry, Jagiellonian

University, Ingardena 3, 30-060 Kraków.

We study a simple situation when the diffusion in parabolic potential is described in terms of the Gaussian wave packet of the following form [1,2]

−−−

−=

))(1(2

))('(exp

)(1

1),',(

2

2

2 tM

tMQQ

tMAtQQφ

where: Q and Q’ are the dimensionless polarization reaction coordinates (the initial state is represented by )(tδ centered at Q’) , and )(tM is corresponding autocorrelation function of the reaction coordinate. It can be verified that the Gaussian wave packet satisfies the diffusion equation

),',(ˆ),',( tQQeffLtQQt

φφ =∂∂ , where

∂∂+

∂∂+≡

2

2

1)(ˆQQ

QtDeffL

with time dependent diffusion coefficient )(tD . The time dependence of the diffusion coefficient assumes very simple form

t

tMtD

∂∂−= )(ln

)( .

For exponential relaxation )/exp()( τttM −= , the diffusion coefficient is time independent τ/1)( =tD . In more general cases, the diffusion coefficient is function of time. Here we consider

simple examples when the relaxation function is given by the following functions: Gaussian, Kubo [3], exponential and stretched exponential [4]. They represent situations when diffusion coefficients are increasing or decreasing functions of time.

Using two surface model and Zusman equations[1,2] the rates of the electron transfer process have been calculated for the corresponding relaxation functions )(tM . In particular we present the results for the time dependences of the electron transfer rates and the initial state populations. The initial rates and the rate coefficients at long time limit are compared with the limiting case of very fast diffusion (Marcus limit). [1] L.D.Zusman, Chem.Phys., 119, 51 (1988) [2] T.Fonseca, J.Chem.Phys., 91,2869 (1989) [3] R.Kubo, Fluctuations, Relexations and Resonance in Magnetic Systems, Oliver and Boyd, London 1061, pp (23-68 [4] M.N.Berberan-Santos, E. N.Bodunow, B. Valeur , Springer Ser Fluoresc., 4, 67-103 (2008)

Plenary Lectures


Molecular features in complex environment: cooperat ive team

players during excited state bond cleavage

Sebastian Thallmair, Matthias Roos, Benjamin Fingerhut, Regina de Vivie-Riedle [email protected]

Department Chemie, Ludwig-Maximilians-Universität, München

Photoinduced bond cleavage is often employed for the generation of carbocations, which are central to SN1 reactions. Benzhydryl derivates are prominent precursors in organic chemistry. Depending on the leaving group, the photoinduced bond cleavage occurs on a femtosecond to picosecond time scale and typically leads to two distinguishable products, the desired benzhy-dryl cations and as competing by-product the benzhydryl radicals. Conical intersections are the chief suspects for such ultrafast branching processes. We show for two typical examples, the neutral benzhydrylchloride and the charged diphenylmethyltriphenyl-phosphonium ions that the role of the conical intersections depends on the interplay of molecular features with the envi-ronment. It turns out to differ significantly for both precursors.

Our analysis is based on quantum chemical, quantum dynamical and on-the-fly calculations. The experimental optical signal we use for comparison is recorded by the Riedle group (LMU, Physik) with high temporal resolution. In case of benzhydrylchloride we can directly connect the observed signals to two early conical intersections close to the Franck Condon region, in case of the diphenylmethyltriphenylphosphonium ion dynamic solvent effects are needed to activate a conical intersection at larger distances along the reaction coordinate. Including the dynamic effect of the solvent, we could clarify the individual bond cleavage mechanism and outline how chemical modifications can be used to control the dissociation and the stability of the carbo-cations independently.

Invited Lectures


Invited Lectures

Invited Lectures


Importance of bleaching bands in ultrafast UV-vis a nd mid-IR transient absorption studies of aryl azides, diazo esters and

ketones, 1,2,3-thiadiazoles, bis-benzoxazoles, and natural pigments

Burdziński G.

Faculty of Physics, Adam Mickiewicz University in Poznań, Poland, [email protected]

Ultrafast time-resolved UV-vis and mid-IR transient absorption spectroscopies are nowadays common techniques to describe kinetics and dynamics of photoinduced processes in organic molecules. Mostly during measurements we are focused on positive absorption bands corresponding to intermediates or persistent photoproducts. Observation of the negative band related to the depletion of precursor is less intriguing, because it reflects spectral position and shape of steady-state absorption band. However it often provides valuable information on: pho-toreaction and internal conversion quantum yields. Reversible nature of photochemical pro-cesses can be confirmed by a full ground state recovery. In case of very fast (<1 ps) internal conversion process (S1→hot S0), over a few tens of ps, the bleaching band is typically affected by overlap with the spectrum of a hot S0 species. In this talk numerous examples will be pre-sented,1 including recently recorded data for some natural pigments. 1. (a) Burdzinski, G.; Middleton, C.; Gustafson, T.; Platz, M., Solution phase isomerization of vibrationally excited singlet nitrenes to vibrationally excited 1,2-didehydroazepine. J. Am. Chem. Soc. 2006, 128, 14804-14805; (b) Burdzinski, G.; Rehault, J.; Wang, J.; Platz, M. S., A study of the photochemistry of diazo Meldrum’s acid by ultrafast time-resolved spectroscopies. J. Phys. Chem. A 2008, 112, 10108-10112; (c) Burdzinski, G.; Zhang, Y.; Wang, J.; Platz, M. S., Concerted Wolff rearrangement in two simple acyclic diazocarbonyl compounds. J. Phys. Chem. A 2010, 114, 13065-13068; (d) Burdzinski, G.; Luk, H. L.; Reid, C. S.; Zhang, Y.; Hadad, C. M.; Platz, M. S., The photochemistry of 4,5-carbomethoxy-1,2,3-thiadiazole: direct observation of thiirene formation and its decay in solution. J. Phys. Chem. A 2013, 117, 4551-4555; (e) Wnuk, P.; Burdzinski, G.; Sliwa, M.; Kijak, M.; Grabowska, A.; Sepioł, J.; Kubicki, J., From ultrafast events to equilibrium - uncovering the unusual dynamics of ESIPT reaction. The case of dually fluorescent diethyl-2,5-(dibenzoxazolyl)-hydroquinone., in preparation; (f) Lezner, T.; Ehlers, F.; Scholz, M.; Oswald, R.; Oum, K., Assignment of carotene S* state features to the vibrationally hot ground electronic state. Phys. Chem. Chem. Phys. 2010, 12, 8832-8839.

Invited Lectures


e-

e-

e-

e-

Fig.1 Schematic picture of DSSC.

Ultrafast studies of charge transfer processes in d ye-sensitized

solar cells

Ziółek M.1

1 Faculty of Physics, Adam Mickiewicz University in Poznan, Poland; [email protected]

Dye-sensitized solar cells (DSSC), introduced for the first time quite recently, in a pioneering work in 1991 [1], belong to the new generation of solar cells. The working principle of DSSC (Fig. 1) is the interaction between the dyes (metal complexes or pure organic compounds) with semiconductor metal oxide nanoparticles (most often TiO2) to which the dyes are attached [2].

The nanoparticles covering one of the photo-cell’s electrodes form a mesoporous structure of a very large effective surface area. The final charge separation whose efficiency deter-mines the solar cell performance is achieved by partial charge separation processes: elec-tron injection from the light-excited dye into a metal oxide nanoparticle, electron transfer from the electrolyte to the dye and electron transport through the network of nanoparticles to the electrode [2].

Ultrafast time-resolved studies are oriented towards the determination of the electron injection rate and the dynamics of other, com-petitive and unwanted processes, like back

electron transfer from metal oxide to the dye and the internal deactivation of the dye. The recent studies indicate the importance of the measurements performed for the real, complete solar cells, for which the dynamics can be different to that measured in separate systems [3].

In this talk, the author’s contribution to the studies of the interaction between organic dyes and metal oxide nanoparticles will be briefly presented. The implemented techniques are femto-second transient absorption and time-resolved fluorescence (up-conversion). First, the meas-urements in suspensions will be shown for the system of the dye from triphenylamine family (TPC1) interacting with nanoparticles of different metal oxides [4], TiO2 nanotubes [5] and TiO2-doped mesoporous silica materials [6]. Then, the studies in thin films will be discussed [7]. Fi-nally, the results obtained for complete DSSC will be presented, including the studies of an efficient TH305 dye [8] as well as very recent results for red-absorbing dye, HY103, and a popu-lar indolene-based dye D149.

[1] B. O'Regan and M. Grätzel, Nature, 353, 737 (1991) [2] A. Hagfeldt, G. Boschloo, L. Sun, L. Kloo, H. Pettersson, Chem. Rev. 110, 6595 (2010) [3] A. Listorti, B. O'Regan and J. R. Durrant, Chem. Mater., 23, 3381 (2011) [4] C. Martín, M. Ziółek, M. Marchena, A. Douhal, J. Phys. Chem. C., 115, 23183 (2011) [5] M. Ziółek, I. Tacchini, M. T. Martínez, X. Yang, L. Sun, A. Douhal, Phys. Chem. Chem. Phys., 13, 4032 (2011) [6] M. Ziółek, C. Martín, M. T. Navarro, H. Garcia, A. Douhal, J. Phys. Chem. C, 115, 8858 (2011) [7] M. Ziółek, B. Cohen, X. Yang, L. Sun, M. Paulose, O. K. Varghese, C. A. Grimes, A. Douhal, Phys. Chem. Chem. Phys., 14, 2816 (2012) [8] M. Ziółek, C. Martín, L. Sun, A. Douhal, J. Phys. Chem. C, 116, 26227 (2012)

Invited Lectures


Processing information with light and molecules

Konrad Szaciłowski1, 2

1 Faculty of Non-Ferorus Metals, AGH University of Science and Technology

2 Faculty of Chemistry, Jagiellonian University, [email protected]

Information, along with energy and matter, is one of the fundamental entities that built the Universe [1]. Light, usually considered as the cleanest form of energy is also a powerful infor-mation carrier. While interaction of light with molecules is studied in detail, these processes are very seldom associated with information processing [2].

The simplest molecular devices that can be considered as information processing enti-ties are chemosensors. These devices take chemical information as an input and release infor-mation in the form of changed in optical properties (absorption or emission). The utility of chemosensors as computing devices is, however, limited by molecular design and synthesis: any Boolean operation requires specially designed molecules. Furthermore, the serious obsta-cle of concatenation of these devices strongly reduces their complexity [3].

Our current approach combines paradigms of chemical sensing and classical, semi-conductor-based electronics. Novel materials are synthesized via chemisorption of organic redox-active chromophores or chromogenic molecules onto wide bad gap semiconductors. These materials are characterized by pronounced photoelectrochemical photocurrent switching effect or other photoelectrical instabilities. By careful selection of substrate potential and inci-dent light wavelength different information processing devices have been demonstrated. These simple logic devices can be subsequently connected into larger circuits which leads to construc-tion of simple optoelectronic arithmetic circuits [4, 5].. Moreover, in the presence of appropriate charge trapping agents, memory effects can be observed, which ultimately leads to neuromi-metic computing architectures.

Fig. 1. Redox umpolung of strong electron acceptors at n-type TiO2 surfaces.

[1] Roederer JG. Information and its Role in Nature. Heidelberg: Springer-Verlag 2005.

[2] Szaciłowski K. Infochemistry. Information Processing at the Nanoscale. Chichester: John Wiley & Sons

2012.

[3] Szaciłowski K. Digital information processing in molecular systems. Chem Rev. 2008;108:3481–548.

[4] Gawęda S, Kowalik R, Kwolek P, Macyk W, Mech J, Oszajca M, et al. Nanoscale Digital Devices Based

on the Photoelectrochemical Photocurrent Switching Effect: Preparation, Properties and Applications.

Isr J Chem. 2011;51:36-55.

[5] Gawęda S, Podborska A, Macyk W, Szaciłowski K. Nanoscale optoelectronic switches and logic devices.

Nanoscale. 2009;1:299-316.

Invited Lectures


catechol,salicylate

catechol

Figure. Possible mechanisms of singlet oxygen generation involving the Nosaka’s mechanism (left) and NIR-induced energy transfer (right).

Singlet oxygen generation in titanium dioxide collo ids.

The effect of NIR irradiation

Wojciech Macyk,1 Marta Buchalska,1 Przemysław Łabuz,1 Tadeusz Sarna,2 Sebastian Maćkowski3

1 Faculty of Chemistry, Jagiellonian University, ul. Ingardena 3, 30-060 Kraków, Poland

2 Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland

3 Institute of Physics, Nicolaus Copernicus University, Grudziądzka 5, 87-100 Toruń, Poland

Singlet oxygen can be generated in aqueous colloids of nanocrystalline TiO2 modified by or-

ganic ligands forming surface titanium(IV) complexes. Our studies revealed a plausible and unique influence of near-infrared irradiation in this process. The formation of 1O2 has been con-firmed by direct and indirect methods, involving time-resolved measurements of singlet oxygen phosphorescence, and fluorescence measurements of the oxidized Singlet Oxygen Sensor Green (SOSG). TiO2 colloids modified with salicylic acid appeared the most efficient heteroge-neous photosensitizer generating 1O2 among the tested materials. The measured quantum yield reached 0.012 upon irradiation at 355 nm, while pristine TiO2 colloids appeared to be substan-tially less efficient showing the corresponding quantum yield of ca. 0.003. The irradiation condi-tions (UV, vis, NIR or any combination of these spectral ranges) influence the generation of both

singlet oxygen and hydroxyl radicals. Simultaneous irradi-ation with visible and near-infrared light did not acceler-ate formation of hydroxyl radicals; however, catechol-modified TiO2 influenced 1O2 generation. Although singlet oxygen is presumably formed according to the Nosaka’s mechanism (O2

•− oxidation with a strong oxidant, like hole or an oxidized ligand), the energy transfer from NIR-excited titanium(III) centers (trapped electrons) plays also a plausible role (Figure).

The financial support from the TEAM program ‘Activation of small molecules in photocatalyt-ic systems’ awarded by the Foundation for Polish Science is gratefully acknowledged.

[1] T. Daimon, Y. Nosaka, J. Phys. Chem. C, 2007, 111, 4420. [2] M. Buchalska, P. Łabuz, Ł. Bujak, G. Szewczyk, T. Sarna, S. Maćkowski, W. Macyk, Dalton Trans.

2013, 42, 9468.

Invited Lectures


Spotlight on Dipole-bound Anions

Sylwia Freza

Department of Chemistry, University of Gdańsk, Sobieskiego 18, 80-952 Gdańsk, Poland

Corresponding Author e-mail: [email protected]

Binding an excess electron to a polar molecule results in forming a dipole-bound state of an-ion. Albeit the existence of those anions was confirmed in the past, the issue of theoretical ab initio level required to reproduce their electron binding energies was not properly addressed until the late 90s when the crucial role of dispersion interaction for the stability of dipole-bound anions was revealed. As it turned out, the electrostatic interaction between the excess electron and the polar neutral molecule, although necessary, is not dominating in most cases (in particu-lar for weakly bound systems) whereas the dispersion interaction between the excess electron and electrons of the neutral molecule is usually recognized as sizeable stabilizing contribution.

An excess electron in a typical dipole-bound anion is highly diffused and localized mostly outside the molecu-lar framework. In particular, it does not reside in a con-ventional valence orbital but in an orbital whose size, shape, and binding energy is governed to a large extent by the long-range potential of the molecule. Hence, dipole-bound anions are usually weakly bound systems having small electronic stabilities and exhibiting the equilibrium geometrical structures resembling those of their corresponding parent neutral molecules.

The representative examples of such anions, their properties and the role they play in various physico-

chemical processes will be discussed. In addition, the issue of binding two excess electrons to a polar molecule will be addressed (together with the examples of much more extraordinary mixed valence-dipole dianions, bi-dipole mono- and dianions).

Panel Discussion


Panel Discussion

Solvation Dynamics

Panel Discussion


Panel Discussion:

Solvation dynamics - Introduction to Panel Discussi on

Karpiuk J.

Institute of Physical Chemistry, Polish Academy of Sciences, [email protected] Most chemical reactions and biological processes take place in the liquid phase where solvent provides an active contribution to the reaction dynamics. Quite often the solvent controls the course of the reactions and processes by changing energies of the states involved. A complete understanding of interactions leading to solvent-assisted processes, including especially pho-toindued electron transfer, is of fundamental importance for the liquid state chemistry. One possible view of how the solvent assists the electron transfer reaction has been presented by Calef and Wolynes exactly 30 years ago:

"In summary we have the following picture of the electron transfer process in a polar fluid. An electron is initially localized in one part of the reaction complex. The polari-zation of the surrounding solvent is on the average the equilibrium polarization ap-propriate to that charge distribution. The solvent polarization is fluctuating around that average. Occasionally an arrangement of solvent molecules will occur that will equate the energies of the initial and final localized electronic states. This fluctuation, which persists for a long time on the time scale of electron motion, allows the charge to transfer without emitting or absorbing radiation. The fluctuations in the polarization continue, and, if the polarization relaxes to a state solvating the product, the electron-transfer reaction has been completed. To understand the rate of electron transfer, we will need to know the rate at which these fluctuations occur."

Are that only fluctuations of solvent polarisation which bring about the electron transfer reac-tion? Do we agree with that picture? Are we intellectually satisfied with this description? Or maybe there is a place for new concepts and language? [1] D. F. Calef, P. G. Wolynes, J. Phys. Chem. 87, 3387-3400 (1983).

Panel Discussion


Panel Discussion:

Solvation Dynamics – Mechanisms and Effects

Mark Maroncelli

Department of Chemistry, The Pennsylvania State University, [email protected]

“Solvation dynamics” is the response of a medium to electrostatic solute perturbations, typically observed by monitoring the dynamic Stokes shift of a fluorescent probe after electronic excita-tion. This phenomenon is a fundamental characteristic of polar media and it is central to an environment’s influence on charge motion and charge-transfer reactions. Solvation dynamics was first considered in the 1960s and has been studied in various contexts ever since: in conventional polar solvents, in proteins and other organized media, and most recently in ionic liquids.

Solvation dynamics is closely tied to dielectric relaxation. Virtually all theories of solvation dy-namics rely on information from dielectric experiments in order to predict the time dependence of solvation. In some cases, even very simple models are able to predict the observed dyna-mics with surprising accuracy if good dielectric data are available. Computer simulations have provided insight into the molecular motions responsible for the solvation response: solvent reorientation in the case of strongly dipolar solvents, ion translation in the case of ionic liquid solvents, and strongly coupled macromolecule + water motions in the case of biological envi-ronments. While no “ab initio” theories capable of accurately predict the solvation response in realistic situations exist, our understanding of solvation dynamics is fairly well developed, at least in the case of simple homogeneous solvents.

Less complete is our understanding of the connection between solvation dynamics and the electrostatic (“dielectric”) friction on solute motion and reaction. For example, linear solvation theories predict a direct connection between the solvation response and the time-dependent friction on rotation of a dipolar solute. Diffusion of ions is also closely connected with time-dependent solvation. However, in neither case has this connection been convincingly demon-strated experimentally. In the case of charge-transfer reactions, the simplest connection to solvation arises for essentially barrierless adiabatic reactions. When intramolecular modes are relatively unimportant, the reaction coordinate is comprised of solvent degrees of freedom and clear correlations between reaction and solvation rates are known for several reactions. But the presence of significant intramolecular reorganization and/or reaction barriers complicates inter-pretation of experimental data. In such cases few unambiguous demonstrations of the solvation dynamics – reactive friction connection are yet available.

Panel Discussion


Panel Discussion:

Photocatalysis - a complex interplay of solvation, geometric relax-ation, electron transfer and diffusional dynamics

Riedle E., Wenninger M.

LS für BioMolekulare Optik, LMU München, [email protected]

In photocatalysis a chromophore is excited with a wavelength that does not induce direct photochemistry in the substrate [1]. The deposited energy is then used in many cases for an electron transfer from the catalyst to the substrate or vice versa. As the electronically excited catalyst is dissolved in a polar medium, any relaxation - either by classical solvation or geomet-ric relaxation - can influence the ability for ET and to induce the subsequent chemistry in the substrate.

We will discuss a number of recent examples that demonstrate this complexity [2,3,4]. We hope that the discussion will boost the awareness of the audience for the need to disentangle the individual contributions and to take the step from "just" solvation to the "full story".

[1] "Time resolved spectroscopy in photocatalysis", Matthias Wenninger and Eberhard Riedle, Chemical

Photocatalyis (Ed.: Burkhard König), De Gruyter (2013). [2] "Unraveling the flavin-catalyzed photooxidation of benzylic alcohol with transient absorption spec-

troscopy from sub-pico- to microseconds", U. Megerle, M. Wenninger, R.-J. Kutta, R. Lechner, B. König, B. Dick, E. Riedle, Phys. Chem. Chem. Phys. 13, 8869-8880 (2011).

[3] "Intramolecular [2+2] Photocycloaddition of 3- and 4-(But-3-enyl)oxyquinolones: Influence of the Al-kene Substitution Pattern, Photophysical Studies and Enantioselective Catalysis by a Chiral Sensi-tizer", Mark M. Maturi, Matthias Wenninger, Rafael Alonso, Andreas Bauer, Alexander Pöthig, Eber-hard Riedle, Thorsten Bach, Chem. Eur. J. 19, 7461-7472 (2013).

[4] "Conformational control of benzophenone-sensitized charge transfer in dinucleotides", Th. Merz, M. Wenninger, M. Weinberger, E. Riedle, H.-A. Wagenknecht, M. Schütz, Phys. Chem. Chem. Phys., accepted for publication.

Oral Communications


Oral Communications

Oral Communications


Fig.1 Transient absorption of pyrene with

5 mM dimethylaniline in acetonitrile.

Broadband UV-VIS transient absorption spectroscopy in the nano-second to microsecond time domain with sub-ns time resolution

Lang B., Mosquera-Vázquez S., Rosspeintner U. and Vauthey E.

Institute of Physical Chemistry, University of Geneva, Switzerland, [email protected]

A combination of sub-nanosecond photo excitation and femtosecond supercontinuum

probing has been used to extend femtosecond transient absorption spectroscopy into the nanosecond to microsecond time domain. Employing a passively Q-switched frequency tripled Nd:YAG laser and determining the jitter of the time delay between excitation and probe pulses with a high resolution time delay counter on a single-shot basis leads to a time resolution of 350ps. Single-shot referencing of the supercontinuum probe with two identical spectrometer /

CCD arrangements yields an excellent signal-to-noise ratio in short to moderate accumulation times. The time overlap of almost an order of magnitude between fs and ns excitation mode permits to extend ultrafast transient absorption experiments seamlessly into time ranges traditionally covered by laser flash photolysis, with the added benefit of a broadband detection covering the entire visible spectral domain and the near UV. It is furthermore possible to study ultrafast parts of the dynamic beyond the time resolution of a typical flash photolysis set-up without changing the detection system.

Figure 1 shows as an application example tran-sient absorption of pyrene with 5 mM dimethylaniline in acetonitrile. The lower part has been measured using femtosecond excitation, the upper using sub-nanosecond excitation. Upon photo excitation, the exited state absorption rises within time resolution and red-shifts subsequently by about 10nm due to solvation dynamics. After some tens of picoseconds, a band attributed to the Py●− radical anion starts to rise around 500nm, indicating a quenching of the Py* S1 state by electron transfer from DMA. A further

band at 420nm attributed to the Py triplet state is growing in on the timescale of a few nanosec-onds. The corresponding triplet state population stems predominantly from triplet recombination of the radical ion pairs.

This example demonstrates the ability of the set-up to cover the entire time scale of the pho-to cycle from photo excitation with subsequent ultrafast dynamics until the return of all reaction products to the neutral ground state. Further applications will be presented at the conference.

[1] B. Lang et al., Rev. Sci. Instr. 87, 73107 (2013)

Oral Communications


O

O

N(CH3)2(CH3)2N

(CH3)2N

O

O

N(CH3)2(CH3)2N

O

O

N(CH3)2(CH3)2N

(CH3)2N

O

O

N(CH3)2(CH3)2N

CVLB MGLB

CVL MGL

Ultrafast excited-state dynamics of spirocyclic

bichromophoric D–A systems

Karpiuk J.1, Majka A.1, Karolak-Solarska, E.1, Nowacki J.2

1 Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01 – 224 Warsaw, [email protected]

2 Institute of Physics, Polish Academy of Sciences, 02-668 Warsaw, Al. Lotników 32/46, Poland

Interchromophoric interactions in excited multichromophoric molecules can lead to fast pho-tophysical and photochemical processes that occur in parallel with relaxation of the optically populated excited state along vibrational and solvational coordinates. An interesting example of entangled ultrafast photochemistry, photoinduced electron transfer, solvation and vibrational

relaxation is provided by spirocyclically bridged derivatives of triarylmethane lactones, CVLB and MGLB . Similarly as in their non-bridged precursors, crystal violet lactone (CVL) and malachite green lactone (MGL), both CVLB and MGLB relax to a fluorescent locally excited (the same in non-polar and different in polar solvents in both molecules) and a highly polar charge transfer states [1,2], and the sp3 carbon link between the electron donating and electron accepting subunits provides an efficient scaffold for ultrafast electron transfer [3,4]. Unlike non-bridged precursors, rigidized CVLB and MGLB

structures show dramatic fluorescence loss with fluorescence quantum yields and lifetimes reduced by more than 3 orders of magnitude as compared with their non-bridged counterparts.

Transient absorption studies indicate that the main relaxation pathway in CVLB is rapid dis-sociation of the C–O bond in the lactonic ring of the 6-DMAPd subunit [5], and preliminary re-sults suggest analogous deactivation mechanism for MGLB . The dissociation occurs from vibra-tionally non-relaxed levels of the primarily excited state on the time scale of solvation dynamics and is accompanied by a parallel relaxation to a highly polar CT emissive state. The case re-sembles structurally similar rhodamine lactones [6], indicating general importance of both dia-batic and adiabatic ring opening in photophysics of spirocyclic donor–acceptor systems.

[1] J. Karpiuk, J. Phys. Chem. A 108, 11183-11195 (2004). [2] J. Karpiuk, Phys. Chem. Chem. Phys. 5, 1078-1090 (2003). [3] T. Bizjak, J. Karpiuk, S. Lochbrunner, E. Riedle, J. Phys. Chem. A 108, 10763-10769 (2004). [4] U. Schmidhammer, U. Megerle, S. Lochbrunner, E. Riedle, J. Karpiuk, J. Phys. Chem. A 112, 8487-

8496 (2008). [5] E. Karolak-Solarska, Photoinduced electron transfer in triarylmethane lactones. Photophysics-structure

relationship, doctoral dissertation, Institute of Physical Chemistry PAS, Warsaw, 2013. [6] (a) U. K. A. Klein, F. W. Hafner, Chem. Phys. Lett., 43, 141-145 (1976); (b) T. M. Grigoryeva, V. L.

Ivanov, N. Nizamov, M. G. Kuzmin, Dokl. Akad. Nauk 232, 1108-1111 (1977); (c) J. Karpiuk, Z. R. Grabowski, F. C. De Schryver, J. Phys. Chem. 98, 3247–3256 (1994).

Oral Communications


Fig.1 Molecular logic devices based on Q@TiO2

Molecular logic devices based on photosensitized Ti O2

Podborska A.1, Szaciłowski K.1,2

1 Faculty of Non-Ferrous Metals, AGH University of Science and Technology,

[email protected] 2 Faculty of Chemistry, Jagiellonian University

Titanium dioxide (TiO2) is one of the ‘famous’ wide band gap semiconductors, but his huge

disadvantage is light absorption only in ultraviolet range. In order to improve the optical proper-ties of TiO2 the surface of semiconductor is modified with different organic molecules.[1]

The interesting group of mol-ecules which could be used as photosensitizers are 1,4-benzoquinone and its derivatives (DDQ, chloranil, fluoranil, chlo-ranilic acid, DQ, etc.). The chem-istry of quinones is a very broad field of research due to specific electronic structures and proper-ties. Quinones are a special

group of molecules, which undergo easily reversible oxidation-reduction reactions and they are excellent electron carriers. Due to influence of functional groups, quinones may have various values of the standard redox potential.[2]

Surface modification of TiO2 with benzoquinone derivatives results in new hybrid materials with unique optical and photoelectrochemical properties. The electrodes made from these mate-rials show strong photosensitization of TiO2 under visible light (700 nm). What is more im-portant, the photoelectrochemical photocurrent switching effect (PEPS effect) was observed for this materials.

New hybrid materials based on Q@TiO2 can be successfully used to construction of simple logic devices: logic gates, multiplexers or optoelectronic switches.[3]

[1] W. Macyk, et.al., Coord. Chem. Rev., 254, 2687-2701 (2010) [2] M. Bauschner, W. Mantele, J. Phys. Chem., 96, 11101-11108 (1996) [3] K. Szaciłowski, Infochemistry. Information Processing at the Nanoscale (Wiley, 2012)

Oral Communications


Fluorescence spectroscopy: the journey of the photo n, and what is important for measuring corrected spect ra

Gilchrist, J.R.

Gilden Photonics Ltd., 13-14 Telford Court, 9 South Avenue,

Clydebank Business Park, Clydebank, G81 2NR, UK. Email: [email protected]

The scope of optical spectroscopy methods is very wide and encompasses many aspects of

life- and material science. Using optical spectroscopy one can analyse spectro-chemical

events to monitor, for example, human health issues, food and water quality, environment

quality, materials for whitening agents, lighting and light emitting diodes. The instrumenta-

tion used comprises of optical, mechanical, electrical as well as signal processing and data

analysis components. The data recorded is a convolution of the effects of each of these com-

ponents in addition to the sample and its behaviours.

Fluorescence spectroscopy, although not a new technique, is still compared to other analyti-

cal methods relatively immature in terms of standardisation of measurement. More than a

100 years later, commercial fluorimeter system emerged as advances in light sources, scan-

ning monochromators, detector technology, and analogue signal recording mechanisms be-

came available. In the last 50 years there have been considerable improvements in each

electro-optical component used in fluorimeter systems but, equally, there has also been a

rapid advancement to computer controlled, often termed “black-box”, technology. As a result

in recent decades less attention has been given to the measurement of instrument perfor-

mance and in particular to rigorous calibration and testing. The observed measured spec-

trum is the convolution of both the experimental system and the true fluorescence spectrum.

Some experimentalists that are not fully acquainted with measuring fluorescence spectra

may, understandably, take a black box approach to these important aspects of measuring

fluorescence spectra. Even so, it is important that we appreciate this convoluted system if we

are to gain a quantitative insight from the fluorescence measurements that we observe that

are related to the samples that have been analysed as opposed to the measurement system.

References:

1. The Infrared Handbook, WL Wolfe & GJ Zissis, Office of Naval Research 1978

2. SpectroChemical Analysis, JD Ingle jr & SR Crouch, Prentice Hall 1988

3. The Design of Optical Spectrometer, JF James & RS Sternberb, Chapman & Hall Ltd.,

1969

4. Spectrograph Design Fundamentals, John James, Cambridge Univeristy Press 2007

5. IUPAC Glossary of Terms used in PhotoChemistry, Pure Appl. Chem., Vol. 79, No. 3,

pp. 293–465, 2007

6. Standardisation & Quality Assurance in Fluorescence Measurements I, Editor: Resch-

Genger, U, Springer-Verlag, 2008

Oral Communications


Synchronous Fluorescence Spectroscopy:

Methods and Applications

Gierszewski Ma., Prukała Da., Sikorska Eb., Sikorski Ma.

Faculty of Chemistry, Adam Mickiewicz University in Poznań, [email protected] Poznań University of Economics, al. Niepodległości 10, Poznań

In systems containing several fluorophores, single-wavelength spectra are usually insufficient for a comprehensive description of fluorescent properties, thus multidimensional measurement methods should be used. The most comprehensive characterization of a multicomponent fluo-rescent system is obtained by measurement of an excitation-emission matrix, known also as a total luminescence spectrum or fluorescence landscape. This technique was first introduced by Weber [1]. After the first application to edible oils by Wolfbeis & Leiner [2], it has been intensive-ly used for exploring oil fluorescence. Total luminescence spectra are usually obtained by measurement of emission spectra at several excitation wavelengths. They may be presented as a three dimensional plot, with the fluorescence intensity plotted in function of the excitation and the emission wavelengths [3,4]. Another representation of the total luminescence is obtained using two-dimensional contour maps, in which one axis represents the emission and another – the excitation wavelength, and the contours are plotted by linking points of equal fluorescence intensity. However the acquisition of contour maps at sufficient resolution (determined by the number of individual emission spectra recorded) on conventional spectrofluorometers is time-consuming, requiring a large number of scans for each sample. Alternatively, multicomponent fluorescent systems may be investigated by the synchronous fluorescence techniques, proposed by Lloyd [5]. This technique involves simultaneous scanning of both excitation and emission wavelengths, keeping a constant difference between them. Synchronous scanning fluorescence spectroscopy is very useful for the analysis of mixtures of fluorescent compounds, because both excitation and emission characteristics are included into a single spectrum. Although it provides less information than the excitation-emission matrix, it may still present a viable alternative to the total luminescence measurements due to its inherent simplicity and rapidity. A set of synchronous spectra recorded at different wavelength intervals may be concatenated into a total synchronous fluorescence spectrum. In such spectra fluores-cence intensity is plotted as a function of the excitation wavelength and the wavelength interval. In this presentation the application of fluorescence spectroscopy to qualitative and quantitative analysis of samples of different kind will be reviewed. Methodological aspects of fluorescence measurements and analysis of fluorescence spectra will also be discussed. The relation be-tween various kinds of fluorescence spectra will be presented and discussed for number of systems, including both pure and applied photochemical type of studies. This study was supported by the research grant DEC-2012/05/B/ST4/01207 from The National Science Centre of Poland (NCN).

[1] G. Weber. Nature, 190, 27-29 (1961)., [2] O.S. Wolfbeis, M. Leiner. Mikrochimica Acta, 1, 221-233 (1984). [3] T. Ndou T, I.M. Warner. Chemical Reviews, 91, 493-507 (1991). [4] G.G. Guilbault. Practical Fluorescence, Marcel Dekker, (1999), New York. [5] J.B.F. Lloyd. Nature (London) Physical Science, 231, 64-65 (1971).

Oral Communications


Tautomerism in porphycenes: new findings

Waluk J.

Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44,01-224 Warsaw

[email protected]

Porphycenes are structural isomers of porphyrins. Their geometry enables the formation of two strong NH···N hydrogen bonds. Tautomerization along these bonds (Figure 1) occurs in femtoseconds to picoseconds, depending on the substitution pattern. Over the years, numerous papers devoted to tautomerization of porphycenes have been published, making these mole-cules role models for investigating in detail the mechanisms of intramolecular double hydrogen transfer [1].

I will present the results of recent studies on the tautomerism in various porphycenes per-formed under different conditions, ranging from condensed phase experiments down to the level of a single molecule, to the investigations of chromophores isolated in supersonic jets. The issues addressed include multidimensional character of tautomerization path, mode-specific tunnelling, the presence of rare tautomeric forms, and the influence of the environment on the tautomerization potential in single molecules.

NN

NN

H H

NN

NN

H H

NN

NN

H H

NN

NN

H H

transtrans

cis

cis

Figure 1. Tautomerization in porphycene: synchronous (trans-trans, cis-cis) and stepwise (cis-trans-cis) mechanisms.

[1] J. Waluk, in: CRC Handbook of Organic Photochemistry and Photobiology, M. Oelgemoeller, A. Griesbeck, F. Ghetti (Eds.), Taylor and Francis, 2011, pp. 809-829.

[2] J. Waluk, in: Handbook of Porphyrin Science, K. Smith, K. Kadish, R. Guilard (Eds.), World Scientific, 2010, vol.7, pp. 359-435.

Oral Communications


Dexter - type energy transfer in liquid solution.

A new approach to kinetic description

Jędrzej Solarski 1, Gonzalo Angulo 1, Andrzej Kapturkiewicz 1,2

1 Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 War-saw, Poland, [email protected]. 2 Institute of Chemistry, Faculty of Sciences, University of Siedlce,3 Maja 54, 08-110 Siedlce, Poland

The Dexter-type energy transfer [1] from the excited (3*D) metal-to-ligand-charge-transfer triplet state (3*MLCT) to selected organic energy acceptor quenchers (A) have been investigated for several luminescent Ir(III) complexes in organic solvents with different viscosities. Analysis [2] of the obtained kinetic data have been performed in the framework of the Sandros [3] and Balzani [4] models with the main conclusion that both of the models are inadequate for proper kinetic description of the investigated 3*D + A → D + 3*A processes, especially in relation to the energy transfer energetics and solvent viscosity effects. A much more adequate kinetic description seems to be possible assuming that during the energy transfer not only spin but also quantum magnetic number within 3*D…A and D…3*A activated complexes are conserved [5]. The applied approach is proposed as an alternative method for the quantitative explanation of the energy transfer rates in the liquid media.

[1] D.L. Dexter, J. Chem. Phys., 21, 836, (1953) [2] J. Solarski, G. Angulo, A. Kapturkiewicz, J. Photochem. Photobiol. A Chemistry, 218, 58-63, (2011) [3] K. Sandros, Acta Chem. Scand.,18, 2355, (1964) [4] V. Balzani, F. Bolletta, F. Scandola, J. Am. Chem. Soc., 102, 2152, (1980) [5] J. G. Winans, Rev. Mod. Phys., 16, 175, (1944)

Oral Communications


Photoluminescence enhancement of CdSe and CdSe-ZnS nano-

crystals by on-surface ligand modification

Marek Oszajca,a Matteo Amelia,b Christophe Lincheneaub, Serena Silvib, Alberto Credi b and Konrad Szaciłowskia,c

a Faculty of Chemistry, Jagiellonian University, ul. Ingardena 3 30-060 Kraków, Poland. b Dipar-

timento di Chimica “G. Ciamician”, Università di Bologna, Via Selmi 2 40126 Bologna, Italy. c Faculty of Non-Ferrous Metals, AGH University of Science and Technology, Al. A. Mickiewicza

30 30-059 Kraków, Poland. E-mail: [email protected]

Quantum dots (QDs) are semiconductor nanocrystals with diameter varying within the na-nometer regime. They exhibit quantum confinement of the charge carriers, what leads to size-dependent optoelectronic properties (such as tunable energy absorption and emission). QDs are also characterized by a large ratio of atoms localized at the surface, which can be reached by external chemical stimuli and further alter their properties.1,2 This approach, also profiling from the thermal and photophysical stability of QDs, in principle brings up systems, which could be utilized as logic gates and chemical sensors.

Performing logic operations on a given system requires selection of at least two distinguish-able states, which could allow to store and process the information in the binary (or more com-plicated) form. In the case of QDs, the most promising signal is their fluorescence, which can adopt either high or low values upon addition of external species.3 Here we will discuss surface modification of the QDs with molecular species for their utilization as logic gates, and illustrate our recent results in this area.

This work was supported by The National Science Centre (grant № UMO-2011/01/N/ST5/02550) and the EU HYSENS project (№ 263091). M.O. thanks The Foundation for Polish Science for the MPD Programme fellowship co-financed by the EU European Re-gional Development Fund.

1 Somers, R.C; Bawendi M.G.; Nocera D.G. Chem. Soc. Rev. 2009, 36, 579–591 2 Reiss, P.; Protiere, M.; Li L. Small 2009, 2, 154-168 3Gadenne, B.; Yildiz, I.; Amelia, M.; Ciesa, F.; Secchi, A.; Arduini, A.; Credi, A.; Raymo, F.M. J. Mater. Chem. 2008, 18, 2022–2027

Oral Communications


Fig.1 (a) PSI absorption and emission; (b) SIF absorption; (c)

crystal structure of PSI at 2.30 Å; (d) SIF synthesis; (e) sample structure

Plasmon – fluorophore interactions

between cyanobacterial Photosystem I and Silver Isl and Film

Kowalska D.1, Czechowski N.1, Lokstein H.2, Ashraf K.2, Cogdell R.2, Mackowski S.1

1 Institute of Physics, Nicolaus Copernicus University, Toruń, Poland, [email protected]

2 Institute of Molecular, Cell and System Biology, University of Glasgow, Scotland

The process of photosynthesis converts the sunlight energy into the biological energy needed to power life. This phenomenal process ensures our food and most of energy resources

on Earth. The search for efficient and environmentally friendly energy sources is a serious challenge in the last decades. One of the solutions concerns emulating nature and utilizing the mechanism of photosynthesis in photovoltaic devices.

Photosystem I (PSI) is a very efficient biological pigment-protein complex that converts solar energy into chemical energy. It contains 96 chlorophylls and 22 carotenoids per monomer. It captures light energy by large internal antenna

systems and transfers it with high efficiency to the core of the reaction center. Metal-enhanced fluorescence (MEF) occurrs in hybrid structures due to the presence of

localized plasmon resonance in metallic nanoparticles. The plasmon resonance can be used for controlling the optical properties of photosynthetic complexes as well as their photochemistry.

In this work we use Photosystem I (PSI) trimers from Synechocystis sp. PCC 6803 and Silver Island Film (SIF) to construct a hybrid nanostructure. Steady-state and time-resolved fluorescence measurements of the structure show spectrally dependent fluorescence intensity enhancement varying from tens to hundreds of times. Taking into account minute changes observed in the time-resolved measurements, we attribute the fluorescence enhancement to the SIF-induced absorption increase of the PSI. Furthermore, both the enhancement factor and the shape of the emission spectrum strongly depend on the excitation wavelength. Research was supported by EUROCORES project “BOLDCATS” funded by the European Science Fundation.

[1] R.E. Blankenship, Molecular Mechanisms of Photosynthesis (Wiley-Blackwell, 2002) [2] J. R. Lakowicz, Principles of Fluorescence Spectroscopy (Springer, New York, 2006) [3] P. Jordan, Nature, 411, 909 (2001)

Oral Communications


Fig.1 Fluorescence maps a) of isolated PCP complexes and hybrid nanostruc-

tures composed of PCP and b) AuNPs and c) AgNWs.

Florescence microscopy as a suitable technique for studying

plasmon-emitter interactions

Olejnik M., Kowalska D., Krajnik B., Lin G., Hofmann E., Maćkowski S.

1 Institute of Physics, Nicolaus Copernicus University, Toruń, Poland, [email protected]

2 Department of Biology and Biotechnology, Ruhr-University Bochum, Germany

For molecules interacting with metallic nanoparticles (NPs) three major phenomena can occur, depending on the hybrid nanostructure geometry, morphology of metallic nanoparticles, optical properties of components etc. The first one is quenching of the molecule emission in the presence of the metallic nanoparticle. The second phenomenon is enhancement of electric field at the surface of the nanoparticles, resulting in an increase of the fluorescence intensity of fluor-ophore while preserving radiative constant, in this case the absorption rate is enhanced. The last possible behavior is an increase of radiative rate of emitter, which results in both an in-crease of emission intensity of fluorophore as well as shortening of its lifetime [1,2].

We studied plasmon induced fluorescence enhancement of a photosynthetic complex peridinin-chlorophyll-protein (PCP) coupled with spherical gold nanoparticles (AuNPs) and silver

nanowires (AgNWs) (Fig.1). The PCP complex contains two chlorophyll a mole-cules responsible for the emission in the red spectral region. The choice of metallic nanoparticles used for fabricating the hybrid nano-structure was determined by their respective optical properties [3,4].

Using both confocal and wide-field fluorescence microscopy as well as time-resolved fluo-rescence microscopy we are able to acquire coherent and complete picture of mechanisms playing important role in fluorescence enhancement in hybrid nanostructures composed of me-tallic nanoparticles and photosynthetic complexes. For example, we observed and determined the enhancement factor of fluorescence intensity for hybrid nanostructure PCP-Au NPs which reach value around 20 [5].

Financial support from the WELCOME program “Hybrid nanostructures as a stepping-stone towards ef-ficient artificial photosynthesis” awarded by the Foundation for Polish Science is gratefully acknowledged.

[1] M. Olejnik, Ł. Bujak, and S. Mackowski, International Journal of Molecular Sciences,. 13, 1018 (2012) [2] P. Bharadwaj, L. Novotny, Opt. Express, 15, 14266 (2007) [3] D. Kowalska, B. Krajnik, M. Olejnik, M. Twardowska, N. Czechowski, E. Hofmann, and S. Mackowski,

The Scientific World Journal, 2013, 1 (2013) [4] M. Olejnik, B. Krajnik, D. Kowalska, M. Twardowska, N. Czechowski, E. Hofmann, and S. Mackowski,

Applied Physics Letters, 102, 083703 (2013) [5] M. Olejnik, B. Krajnik, D. Kowalska, G. Lin, and S. Mackowski, Journal of Physics: Condensed Matter,

25, 194103 (2013)

Oral Communications


TICT-the most controversial excited state of the last 50 years:

The case of cyanopyridine derivatives.

Jacek Dobkowski, Mariusz Pietrzak

Institute of Physical Chemistry, Polish Academy of Sciences, [email protected] Numerous molecules built of an electron acceptor (A) and electron donor (D) units

linked together by a single bond exhibit a peculiar behavior in their low-lying electronically excit-ed states. The double fluorescence of p-N,N-dimethyl-amino-benzonitrile (DMABN ) was dis-covered more than five decades ago by Lippert and his students [1]. To explain the origin of the dual emission the authors have postulated the solvent-induced excited state inversion of two low-lying ππ* states: Lb and La. During next five decades the anomalous fluorescence was re-ported for the class of para-substituted molecules of the type D-Ar-X, where D – donor, Ar – aromatic ring, X – chromophore, for example cyano or aldehyde groups. Ar-X should be treated as an acceptor group; alternatively, an azaaromatic ring was selected as the acceptor, for ex-ample pyridine.

The Lippert model was accepted over a decade, but new experimental results have stimulated researchers to consider an alternative interpretation. Numerous hypotheses were published to explain the experimental data: excimer or solute-solvent exciplex formation, sol-vent induced pesudo-Jahn-Teller (PJT) effect, cyano group bending (RICT) mechanism, pla-narization associated with a quinoid structure PICT model, and Twisted Intramolecular Charge Transfer (TICT). The latter identifies the polar emitting state with the excited rotamer, its –NR2 group being twisted by 90o with respect to the aromatic ring. A full electron transfer had been assumed from the twisted amino group to the aromatic moiety [2]. The photoinitiated electron transfer (ET) processes and models describing structural changes accompanying the intramo-lecular electron transfer (ICT) were critically analysed and compared in the review article pub-lished by Z.R. Grabowski, K. Rotkiewicz and W. Rettig [3].

In the case of DMABN the authors of the hypotheses specified above agree that short (Fb) and long (Fa) wavelength fluorescence originates from two different states characterized by different dipole moments. The bone of contention was the nature of structural transformation of the DMABN molecule occurring along the path of the photoinduced charge separation reaction.

Using time-resolved (TR) spectroscopy in the femto / picosecond time domain we can record the decay of the primary excited species and the rise of the absorption / emission bands of the secondary individuals. In other words, TR spectroscopy is a useful tool for the under-standing of temporal evolution of the molecular system. Unfortunately on the basis of this tech-nique alone, it is difficult or even impossible to perform logical deduction of the excited state geometry transformation. The NMR technique is usually dedicated to the investigation of the molecules in the ground electronic state. Applying the time-resolved UV-induced NMR tech-nique, it is possible to monitor the temporal perturbation of the population distribution in the ground state and determine unequivocally the excited state relaxation path.

[1] E. Lippert,W.Luder, H.Boos, Advancesin Molecular Spectroscopy, ed. A.Mangini (Pergamon Ox-

ford,1962) p.443 [2] Z.R.Grabowski, K.Rotkiewicz, A. Siemiarczuk, D.J.Cowley, and W.Baumann, Nouv. J.

Chim.,3(1979)443. {3] Z.R.Grabowski, K.Rotkiewicz, W.Rettig,Chemical Reviews, 103(2003)3899).

Oral Communications


Photo-Induced formation and recombination of ions i n bimolecular reactions in solution: a never ending s tory

Angulo G.

Institute of Physical Chemistry, Polish Academy of Sciences, [email protected]

Since Smoluchowski’s seminal contribution [1], the evolution of the description of diffusion influenced bimolecular reactions in solution has experienced several jumps forward. First a finite reaction probability was introduced by Collins-Kimball [2]. Later on, the reaction probability was extended from contact to off-contact reactions (like electron or energy transfer) [3]. All these treatments apply well to irreversible forward reactions like fluorescence quenching, but we had to wait until the beginning of the 90’s to have a theory joining this with the subsequent step of products recombination [4]. Still, the introduction of reversibility was not properly introduced until the advent of the so called Integral and Modified Encounter Theories [5]. The latter, in principle, allows for considering many reaction stages and even different spin states of the species in-volved in the reaction. This way, for example, magnetic field effects involving reversibly formed exciplexes can be modelled [6].

However having received many times experimental confirmation [7], there are limits to the applicability of the theory. We have recently presented an experimental work regarding the orientational correlations in bimolecular reactions which is beyond explanation yet [8], so it is still necessary to develop them further in order to introduce the molecular shape and size. We are also working experimentally on the influence of high intensity on the kinetics and yield of photo-induced reactions, and preliminary data show that the complexity of the problem could be beyond the models too. Another frontier of the theories relates to the crowding effects [9], of significant importance in intracellular reactions: as far as we know there is no mature analytical theory to describe them properly, neither systematic experimental work. Finally, another field that could benefit from the application of these ideas is that of photo-induced charge transfer in polymer blends, as those used in all-organic solar cells. In this latter case a full adaptation of the liquid models is needed [10] in order to provide finally with a critical view to the myriad of unsys-tematic experimental data.

In summary, we want to give you a superficial overall picture about the state of the art of the field of diffusion influenced reactions from both the experimental and theoretical points of view, and try to convince you that there is much yet to do in it.

[1] Smoluchowski, M. Z. Phys. Chem. 92, 129 (1917). [2] Collins, F.C.; Kimball, G.E. J. Colloid Sci. 4, 425 (1949). [3] Tunitskii, N.N.; Bagdasar’yan, Kh.S. Opt. Spectrosc. 15, 303 (1963). Kilin, S.F.; Mikhelashvili, M.S.; Rozman, I.M. Opt. Spectrosc. 16, 576 (1964). Vasil’ev, I.I.; Kirsanov, B.P.; Krongaus, V.A. Kinet. Kataliz 5, 792 (1964). [4] Dorfman, R.C.; Fayer, M.D. J. Chem. Phys. 96, 7410 (1992). Burshtein, A.I. Chem. Phys. Lett. 194, 247 (1992). [5] Burshtein, A.I. Adv. Chem. Phys. 114, 419 (2000). Ibidem, 129, 105 (2004). [6] Kattnig, D.R.; Rosspeintner, A.; Grampp, G. Angew. Chem. Int. Ed. 47, 960 (2008). [7] Rosspeintner, A.; Angulo, G.; Vauthey, E. J. Phys. Chem. A 116, 9473 (2012). Rosspeintner, A.; Koch, M.; Angulo, G.; Vauthey, E. JACS 134, 11396 (2012). Angulo, G.; Kattnig, D.; Rosspeintner, A.; Grampp, G.; Vauthey. E. Chem.: A Eur. J. 16, 2291 (2010). Angulo, G.; Grampp, G.; Neufeld, A.A.; Burshtein, A.I. J. Phys. Chem. A 107, 6913 (2003). [8] Angulo, G.; Cuetos, A.; Rosspeintner, A.; Vauthey, E. J. Phys. Chem. A DOI: 10.1021/jp407203r [9] Dix, J.A. Verkman, A.S. Annu. Rev. Biophys. 37, 247 (2008). [10] Seki, K.; Marumoto, K.; Tachiya M. App. Phys. Exp. 6, 051603 (2013).

Oral Communications


Triplet states in optical studies of single molecul es

Kozankiewicz B.

Institute of Physics, Polish Academy of Sciences, [email protected]

The fluorescence signal of a single molecule, embedded in a solid or liquid environment, is emitted as bunches of photons separated by dark periods when molecule undergoes an inter-system crossing to the long-lived triplet state T1. Distribution of these periods provides infor-mation about the population and depopulation rates o the triplet state. It is obvious to deduce that important requirement for successful detection of a single molecule is a very low value of the former rate (typical triplet yield < 10-5) and a high for the later. The triplet states, although very weakly populated in molecules under consideration, play important role in their optical studies. The triplet state kinetic parameters of single molecules can be deduced from the fluores-cence intensity autocorrelation function. At low (liquid helium) temperatures the triplet state, even in absence of external magnetic field, splits into three spin sublevels giving rise to distinct exponential components in the autocorrelation decay. When temperature increases the spin-lattice relaxation process couples the long- and short-lived components of the T1 and population of the triplet state decays mono-exponentially [1]. A further increase of temperature gradually shortens the mono-exponential decay of the autocorrelation function due to the appearing tri-plet-triplet absorption, from the T1 state of the molecule to its higher triplet states [2]. This ab-sorption is usually lacking at low temperatures. It is important to notice that the triplet state parameters depend on the dye but also on the matrix into which the molecule is embedded. In particular, the triplet population yield can be enhanced by as much as three orders of magnitude, thus making detection of the single mole-cule difficult, when the lowest triplet state of a host matrix is at an energy intermediate between those of the S1 and T1 states of the guest molecule. The analysis, performed at the single mol-ecule level, indicated a new, two-step relaxation channel, which starts with an intermolecular intersystem crossing from the S1 state of the guest molecule to the lower lying triplet excitonic state of the host matrix, followed by a Dexter transfer of the triplet energy back to the T1 state of the guest molecule [3]. One of the major factors in blinking and bleaching of single molecules is the presence and the diffusion of molecular oxygen in the neighborhood of the molecule. The electronic ground state of molecular oxygen is triplet and its encounter with a dye molecule in the triplet T1 state results in triplet-triplet annihilation. This process can transfer molecular oxygen to its highly reactive singlet state, and singlet oxygen is capable to bleach the molecule [4].

[1] M. Białkowska, A. Makarewicz, M. Banasiewicz, B. Kozankiewicz, Chem. Phys. Lett. 555, 131 (2013) [2] M. Banasiewicz, O. Morawski, D. Wiącek, B. Kozankiewicz, Chem. Phys. Lett. 414, 374 (2005) [3] A. Nicolet, M. Kol'chenko, B. Kozankiewicz, M. Orrit, J. Chem. Phys. 124, 164711 (2006) [4] I. Deperasińska, E. Karpiuk, M. Banasiewicz, B. Kozankiewicz, Chem. Phys. Lett. 492, 93 (2010)

Oral Communications


Salicylidene methylamine and its derivatives – the photophysics of

model Schiff bases

Jankowska J.1, Rode M. F.2, Sadlej J.3, Sobolewski A. L.2

1 College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, [email protected]

2 Institute of Physics, Polish Academy of Sciences 3 Department of Chemistry, University of Warsaw

Aromatic Schiff bases belong to a broad family of molecular systems whose photophysics is determined by the excited state intramolecular proton transfer (ESIPT). Their typical features, such as photochromism and the high photostability open the prospects of possible applications in optically driven molecular memories and switching devices. In our investigation we chose one of the simplest aromatic Schiff bases, the salicylidene methylamine (SMA). This system is known for its photochromic properties [1] and has been already primarily investigated by means

of theoretical [2] and experimental [3] methods. We examined in detail the exact mechanism of the photo-transformation between its two pho-tochromic forms [4]. In this communication we present the results of systematic theoretical study of photophysical properties of the isolat-ed SMA molecule and its derivatives. We also show preliminary results of dynamic study of SMA photophysics obtained within on-the-fly approach. The conclusion emerging from the obtained results confirms that molecular sys-tems based on Schiff bases should be consid-ered as good candidates for optically driven, reversible molecular switches and sheds light on the direction in which particular molecular

engineering efforts towards obtaining the efficient devices should be made.

[1] E. Hadjoudis, and I. M. Mavridis, Chem. Soc. Rev. 33, 579 (2004) [2] M. Z. Zgierski, and A. Grabowska, J. Chem. Phys. 113, 7845 (2000) [3] J. Grzegorzek, A. Filarowski, and Z. Mielke, Phys. Chem. Chem. Phys. 13, 16596 (2011) [4] J. Jankowska, M. F. Rode, J. Sadlej, A. L. Sobolewski, ChemPhysChem, 13, 4287 (2012)

Oral Communications


Photoluminescence properties of Bi xLa1-xVO4 solid solutions

Kwolek P.1, Pilarczyk K.2, 3, Tokarski T.1, Lewandowska K.1, 4, Szaciłowski K.1, 3

1 AGH University of Science and Technology, Faculty of Non-Ferrous Metals, al. A. Mickiewicza 30, 30-059

Krakow, [email protected] 2 AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. A.

Mickiewicza 30, 30-059 Krakow 3 Jagiellonian University, Faculty of Chemistry, ul. Ingardena 3, 30-060 Krakow

4 Institute of Molecular Physics Polish Academy of Sciences, ul. M. Smoluchowskiego 17, 60-179 Poznan

Bismuth orthovanadate BiVO4 is a very promising material with potential use mainly as a photocatalyst [1]. Lanthanum orthovanadate LaVO4 in turn is much less commonly applied in this area [2]. Since the cation substitution is very common way for modifying both the band gap energy and the band edge potentials, it seems that in the BiVO4 – LaVO4 system it will be pos-sible to tune at least the band gap width. In general, the substitution of the electropositive cation exhibiting the noble gas configuration as La3+ with the p-block cation as Bi3+ should decrease the value of the band gap of the material [3].

BixLa1-xVO4 solid solutions of tetragonal, zircon-type structure were obtained via a micro-wave assisted hydrothermal route. Pure bismuth orthovanadate and lanthanum orthovanadate were obtained in the monoclinic form. The width of the band gap measured with the diffuse reflectance spectroscopy decreased with the addition of Bi3+ ions from 4.11 eV for pure LaVO4 to about 2.95 eV for the 57 at. % of Bi3+ concentration and remains unchanged with further increase in the Bi3+ content. For pure BiVO4 it reaches 2.54 eV. The photoluminescence spectra indicated, that there is a significant increase in the emission intensity for the tetragonal BixLa1-

xVO4 samples as compared to pure monoclinic BiVO4 and LaVO4. It may be associated with the change of the band gap type from the indirect (pure monoclinic phases) to direct (tetragonal solid solutions). Moreover, samples containing from 10 to 30 at. % of Bi3+ content exhibited unusual, very intense green emission at 2.4 eV. Addition of Bi3+ introduces discrete electronic states within the gap, about 1 eV above the valence band edge, which are partially filled with electrons from the valence band. Moreover up to certain content of bismuth (between 30 and 40 at. %), the deexcitation path involving these states is favoured and manifested as very intense emission at 2.4 eV whereas above the threshold concentration the interband, direct transition dominates - nonetheless the discrete features in the low-energy part of the spectrum are still visible. This may be the reason for vanishing of the intense green emission at higher Bi3+ con-centration.

Conduction band edge potential values were also determined using the electrochemical im-pedance spectroscopy and the Kelvin probe spectroscopy. They remain unchanged with the increasing Bi3+ content. On the basis of the spectroscopic measurements energetic scheme for the investigated system was proposed.

[1] A. Kudo, Y. Miseki, Chem. Soc. Rev. 38, 253 (2008). [2] T. Hou, H. Yang, X. Fan, X. Zhang, Catal. Lett. 141, 1215 (2011). [3] M.R. Dolgos, A.M. Paraskos, M.W. Stoltzfus, S.C. Yarnell, P.M. Woodward, J. Solid State Chem. 182, 1964 (2009).

Acknowledgments:

Financial support from Ministry of Science and Higher Education (grant no. UMO-2011/03/B/ST5/01495) is gratefully acknowledged.

Oral Communications


Photoelectrochemical properties of BiVO 4

Mech J.1, Kwolek P. 1, Szaciłowski K.1,2



The main objective of the work is syn-

thesis and characterization of new optical active hybrid materials based on BiVO4 modified with organic compounds named alizarin and alizarin red S. This material reveals PEPS effect (Photoelectrochemical Photocurrent Switching), the phenomena which enables simple controlling of the direction of photocurrent, by changing one or more parameters: wavelength of inci-dent light, applied potential or concentra-tion of sacrificial electron or hole acceptor in surrounding electrolyte [1-3]. Modifica-tion of prepared semiconductor is realized by surface adsorption of organic molecules from aqueous (alizarin red S) or acetonitrile (alizarin) solutions. The research also includes the influence of morphology of

BiVO4 on photocurrent characteristics. N-type BiVO4 is obtained via microwave assisted hydro-thermal method. By changing the pressure in the autoclave chamber during the synthesis it is possible to modify the shape and dimension of crystallites. This technique leads to clino-bisvanite structure. The character of photocurrent in such material changes significantly with the change of oxygen concentration in electrolyte. In negative potential region strong cathodic pho-tocurrent can be observed (fig.1). What is interesting the maximum of cathodic photocurrents occurs at different wavelength than maximum of anodic ones.

Project was funded by the National Science Center (grant 2011/03/N/ST5/04470) and by Malopolska Scholarship Found for PhD students (grant ZS.4112-212/2010).

[1] Di Iorio, Y., et al., New J. Chem. 37, 969-976 (2013)

[2] Oszajca, M., et al., J. Phys. Chem. C 115, 12187-12195 (2011)

[3] Mech, J., et al., Aust. J. Chem. 63, 1330-1333 (2010)

Oral Communications


Fig. 1. The emission spectra of the Sb2S3 quantum dots

suspended in deionized water; three different concentrations.

Synthesis and properties of antimony sulphide quant um dots

Pilarczyk K.1, 2, Robertson N.3, Szaciłowski K.2, 4

1 AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Cracow, Poland, [email protected]

2 Jagiellonian University, Faculty of Chemistry, ul. Ingardena 3, 30-060 Cracow, Poland 3 EastChem School of Chemistry, University of Edinburgh, West Mains Road,

Edinburgh EH9 3JJ, U.K. 4 AGH University of Science and Technology, Faculty of Non-Ferrous Metals,

al. Mickiewicza 30, 30-059 Cracow, Poland

The fast development of solar cells is one of the most promising ways to meet the growing energy consumption. There were several breakthroughs in this field that are worth-mentioning, one of which is the concept of dye-sensitised solar cell (DSSC) (so called Grätzel cell). The original idea evolved into the systems where dyes were replaced with other sensitizers, such as semiconductor quantum dots or metal nanoparticles.

Among others, antimony(III) sulphide nanostructures are considered good modifiers for sensitised solar cells (SSCs). There are several works covering the use of Sb2S3-based nanomaterials in SSCs and working prototypes showing the energy conversion efficiency at the level of approx. 5% have been presented. The practical approach is supplemented with theoretical studies indicating that the alignment of energy levels in the system composed of TiO2 – which is commonly used in DSSCs – modified with Sb2S3 quantum dots is favourable.

However, there are still some difficulties to overcome – namely the electrochemical degradation of the material and some problems related to the charge carriers transport in Sb2S3 modified SSCs. To better understand these processes the study on unmodified antimony(III) sulphide colloids might prove to be useful.

In this work the straightforward synthesis method and characterisa-tion of spherically shaped Sb2S3 quantum dots are presented. The preparation procedure is described

and the properties of the obtained material are discussed – the results include: transmission electron microscopy (TEM), scanning electron microscopy (SEM), dynamic light scattering measurements (DLS), X-ray powder diffraction (XRD), ultraviolet-visible spectrophotometry (UV-Vis) and fluorescence spectroscopy.

[1] C. E. Patrick, F. Giustino, Adv. Funct. Mater. 21,4663 (2011)

[2] J. A. Chang, J. H. Rhee, S. H. Im, Y. H. Lee, H. J. Kim, S. I. Seok , M. K. Nazeeruddin, M. Grätzel, Nano Lett. 10, 2609 (2010)

[3] Y. Itzhaik, O. Niitsoo, M. Page, G. Hodes, J. Phys. Chem. C 113, 4254 (2009)

Exhibitor presentations





COMEF Aparatura Naukowo-Badawcza, Katowice

COMEF is leading provider of scientific and research equipment in Poland. The company regu-larly acquires new customers and enters new markets. In Poland COMEF represents numerous world leading research and measurement equipment producers for different fields of science and industry, including especially nanotechnology: HORIBA Scientific, HITACHI, Setaram, SUSS, Skyscan, Bruker, Cameca, Spectra-Physics, Ultrafast and many, many others. COMEF has a stable team of staff members, whose qualifications are systematically raised through training and courses. COMEF's employees actively participate in the professional na-tional and international conferences. The COMEF company offers full range of facilities and the training service.

EUROTEK International, Warsaw Eurotek International provides equipment for advanced studies of the emission spectroscopy. Ultrasensitive detection allows to measure spectra and emission lifetimes of samples ranging from bulk to nanoparticles. We present solutions for the quantitave measurements of the quantum yields of upconversion luminescence, new possibilities of using widely tunable laser sources. Picosecond decay sudies of fluorescence excited by the second harmonic of the white light continuum are among the pioneering works performed using versatile commercially available system.

Gilden-Photonics, Cyldebank

Scitec Instruments Polska, Warsaw

Gilden Photonics specialises in making or measuring rainbows: we specialise in only supply instrumentation for optical spectroscopy applications. These products range ranges from spec-troscopy components through to complete turn-key systems. In this talk we will briefly discuss company history and also the product range, including device performance and customisation to meet end-user requirements.

Princeton Instruments, New Jersey

Princeton Instruments designs and manufactures high performance CCD, ICCD and EMCCD cameras for scientific research. A full line of proven Czerny Turner spectrographs allows support for complete systems for spectroscopy from VUV to NIR. Developing both lines out of one hand allows support of most demanding applications like Raman, Cars, LIF, LIBS and many more. Double and Triple Spectrometers as well as innovative designs like the Schmidt-Czerny Turner complete the product line.

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Posters

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Spectroscopic studies of selected

flavonoids in various environments

Borowiak M., Kubicki A. A.

Institute of Experimental Physics, University of Gdańsk, ul. Wita Stwosza 57, 80-952 Gdańsk, Poland

[email protected]

Flavonoids are biologically important substances widely present in plants. Numerous studies have revealed a relevant pharmacological activity of this class of compounds. Anticancer, anti-inflammatory, neuroprotective and enzyme-inhibitory effects have been reported [1].

Flavonols, which are a major class of naturally occurring flavonoids, are of interest to many researchers due to the intramolecular excited state proton transfer process (ESIPT) and “two color” fluorescence behavior[2,3]. The polyphenol structure of these molecules, based on chromen-4-one moiety, number and site of specific hydroxyl groups makes them very sensitive for the environment changes[4]. Manipulating the properties of surrounding solvent molecules can affect the solubility, hydrophobicity, and spectroscopic characteristics of the solutes.

The steady-state absorption and emission spectra, and the time-resolved emission spectra of selected flavonoids in different media were measured. The results and the data analysis are presented and discussed.

[1] B. H. Hawsteen, Pharmacology & Therapeutics 96, 67 (2002)

[2] E. Falkovskaia, P. K. Sengupta, M. Kasha, Chem. Phys Lett., 297, 109 (1998)

[3] D. McMorrow, M. Kasha, J. Phys. Chem., 88, 2235, (1984)

[4] E.de Rijke, H. C.Johi, H. R. Sanderse, F. Ariese, U. A. Th. Brinkman, C. Gooijer, An. Chim. Acta 468, 3 (2002)

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Complicated photophysics of anils and boranils

J. Buczyńska1, M. Pszona1, J. Dobkowski1, P. Wnuk1, D. Frath2, G. Ulrich2, S. Mos-

quera-Vazquez3, E. Vauthey3, R. Ziessel2, J. Waluk1

1 Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52 Warsaw, 01-224 Poland, [email protected]

2 Laboratoire de Chimie Organique et Spectroscopies Avancées (LCOSA), UMR7515 au CNRS, École de Chimie, Polymères, Matériaux de Strasbourg (ECPM)25 rue Becquerel,

67087 Strasbourg, Cedex 02, France 3 Dpt. of Physical Chemistry of the University of Geneva, 30 Quai E. Ansermet,

CH-1211 Geneva, Switzerland Complexation of some anils (aniline-imines) with boron(III) precursors leads to stable boran-

ils that can reveal interesting optical properties [1]. Formation of an intramolecular hydrogen bond, which can take place only in anils, may lead to significant changes in the chemical and photophysical behaviour [2, 3].

R NOH

N

R NOB

N

XX

NO2

NO2

Anils

Boranils

R = F(1), CN(2),

R = F(4), CN(5),

(3)

(6) X = F, Ph

Fig. 1. Anils and their analogous boranils. After electronic excitation, substituted anils can relax via different pathways: (i) intramolecu-

lar proton transfer (PT); (ii) intramolecular electron transfer (ET); (iii) conformational change (twisting or flattening). Stationary and time-resolved fluorescence and transient absorption stud-ies showed that the anils reveal dual emission whereas the boranils, devoid of the hydroxyl group, show a single emission. Dual emission of anils is an evidence of photoinduced proton transfer (PT) from the hydroxyl group to the nitrogen atom which occurs only in anils. This is also confirmed by kinetic isotope effects. The excited state deactivation rate of boranils strongly depends on solvent polarity and the nature of the substituent. Fluorescence quantum yields and lifetimes of boranils drastically decrease in polar solvents. This could suggest that photoinduced electron transfer (ET) occurs in boranils. In anils electron transfer may also exist, but this pro-cess is probably much slower than proton transfer.

[1] D. Frath, S. Azizi, G. Ulrich, P. Retailleau, R. Ziessel, Org. Lett., 13, 3414 (2011) [2] J. Waluk, ACC. Chem. Lett., 36, 832 (2003) [3] J. Herbich, C.-Y. Hung, R.P. Thummel, J. Waluk, J. Am. Chem. Soc., 118, 3508 (1996)

The aim of our investigation was to understand the ex-cited state relaxation pathways in selected anils and bo-ranils. For this purpose, photophysical properties of anils 1-3 were compared with those of analogous boranils 4-6. Boranils cannot form intramolecular hydrogen bond and the relaxation pathway through proton transfer does not exist. Both anils and their analogous boranils possess the same electron donor group (Et2N), whereas the electron acceptor group is fluorobenzene (1, 4), benzonitrile (2, 5) and nitrobenzene (3, 6) (Fig.1).

Posters


15000 18000 21000 24000 27000

0.0

0.2

0.4

0.6

0.8

1.0

MGLN6

6-DMAHN6

NH

NH

N

NH

O

NH

NN

NH

O

NH

NN

N

1600 cm -1

fluor

esce

nce

inte

nsity

[a.u

.]

wavenumber [cm -1]

1500 cm -1CVLN6

Fig.1 Fluorescence spectrum of CVLN6 compared with

compounds modelling individual chromophores.

Dual fluorescence of a hydrazide analogue of crysta l violet lactone

– a solvent effect study

Deluga E.1, Nowacki J.,2 Karpiuk J.1

1 Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, [email protected]


Crystal violet lactone (CVL) displays uniquely broad (FWHM ≥ 9150 cm-1) dual fluorescence from a polar locally excited state (blue band) and a charge-separated intramolecular exciplex

formed in moderately and highly polar media (orange band) [1]. Exploring structure-property relationships for structural analogues of CVL with phthalide deriva-tives as electron-accepting moieties we found that appropriately designed donor–acceptor (D–A) archi-tectures based on a sp3 carbon atom link can suc-cessfully combine two fluorophores in one molecule

to emit very broad fluorescence spectra with easily tunable positions of band maxima and inten-sity ratios [2]. An important detail of these architectures is the sp3 carbon-heteroatom bond providing in phthalide-based CVL derivatives (C–O bond) strong vibronic coupling and identified

with reaction coordinate enabling ultra-fast solvent dynamics-controlled intramo-lecular charge separation. In order to study the effect of the heteroatom on the properties of the reaction coordinate and the rate of the ET process we extended our interest on hydrazide analogues of CVL with C–N bond replacing the C–O bond at the sp3 carbon. A molecule from this class, CVLN6, displays solvent-dependent dual fluorescence, with sol-vent effect similar to that observed in CVL. The analysis of compounds model-ing CVLN6 chromophores, MGLN6 and 6-DMAHN6, shows that although the replacement of O with N has an effect on positions of the band maxima due to

different redox characteristics of phthalide and hydrazide, it does not affect the molecule’s ca-pability to populate two emitting states, one locally excited (localized on 6-DMAHN6 moiety), and another highly polar CT state extending over the entire CVLN6 molecule. Our study shows that the sp3 carbon atom link not only allows for differentiation of the ground and excited-state D–A couplings, but also provides a versatile topology for designing D–A structures displaying spectrally very broad fluorescence emission.

References [1] J. Karpiuk, J. Phys. Chem. A 108, 11183-11195 (2004). [2] J. Karpiuk, E. Karolak, J. Nowacki, Phys. Chem. Chem. Phys. 12, 8804-8809 (2010).

CVL CVLN6

N N

NH

NH

NO

N N

N

O

O

Posters


Excited-state double proton transfer in 5-deazaallo xazines

Gierszewski M., Prukała D., Pędziński T., Sikorski M.

Faculty of Chemistry, Adam Mickiewicz University in Poznań, [email protected]

Excited-state double proton transfer (ESDPT) is one of the well-known photochemical reac-

tion for different derivatives of flavin, including 5-deazaalloxazines. This excited-state process occurs in the presence of acetic acid or pyridine, causing proton transfer from the N(1)-H to the N(10) atom and create an excited-state isoalloxazine-like form of the corresponding alloxazine molecule [1,2]. We used steady-state and time-resolved spectral studies to determine formation of an 5-deazaisoalloxazinic excited state via ESDPT catalyzed by an acetic acid molecule that forms a hydrogen-bond complex with the 5-deazaalloxazine molecule. This isoalloxazinic tau-tomer of 5-deazaalloxazine appears as a separate emissive species with a distinct emission spectrum and lifetime. For comparison, we employed 1,3-dimethyl-5-deazaalloxazine, where this process can’t occur due to the substitution by methyl group at N(1). The changes of emis-sion spectra of 5-DAll and 1,3-Me-5-DAll in CH2Cl2 with growing concentration of acetic acid were shown in Fig. 1A and 1B.

350 400 450 500 550 600

N

N

N O

H

O

1

6 3

2108

4

9

75

light

O

N

N

N O

H

O

1

6 3

2108

4

9

75

H

C

O

R

H H

O

H

C

R

O

Inte

nsity

/ a.

u.

λ / nm

0 0.003 0.009 0.012 0.018 0.029 0.041 0.058

CAA

/ mol dm -3A

350 400 450 500 550 600

N

N

N O

CH3

CH3

O

10 1 2

3456

7

8 9

Inte

nsity

/ a.

u.

λ / nm

0 0.006 0.012 0.023 0.035 0.058

CAA

/ mol dm -3B

Fig. 1. A - Changes in emission spectra of 5-DAll in CH2Cl2 with growing concentration of acetic acid;

the concentrations of acetic acid are from 0 to 0.058 M (λex 360 nm). B. - Changes in emission spectra of 1,3Me-5-DAll in CH2Cl2 with growing concentration of acetic acid; the concentrations of acetic acid are from

0 to 0.058 M (λex 360 nm).

The fluorescence lifetimes were measured for 5-DAll at selected concentrations of acetic acid in CH2Cl2 using λexc = 360 nm and λem = 405, 440, or 500 nm. The emission of 5-DAll at λ= 405 nm reveals the 5-deazaalloxazinic form of this compound, with the lifetime of about 2.8 ns. The emission recorded at λ= 440 nm had two different lifetimes, one of about 3 ns attributed to the 5-deazaalloxazinic form, and the 4.0 ns lifetime attributed to the 5-deazaisoalloxazinic form. The longer-wavelength, 5-deazaisoalloxazinic form dominates at λem = 500 nm, although the 5-deazaalloxazinic form of 5-DAll is still present [3].

This study was supported by the research grant DEC-2012/05/B/ST4/01207 from The Na-tional Science Centre of Poland (NCN).

[1] A. Koziołowa, N.V. Visser, J. Kozioł, M. M. Szafran, J. Photochem. Photobiol. A. 93, 157-163 (1996). [2] M, Sikorski, E. Sikorska, A. Koziołowa, R. G. Moreno, J.L. Bourdelande, R. P. Steer, F. Wilkinson, J. Photochem. Photobiol. B. 60, 114-119 (2001). [3] D. Prukała, M. Taczkowska, I. Khmelinskii, M. Gierszewski, T. Pędziński, M. Sikorski, in preparation

Posters


Structural distortion and state inversion effects i n the 1,4-

diazatriphenylene cooled in supersonic jets.

Gil M., Kijak M., Mengesha E., Grabowska A., Sepioł J.

Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, [email protected]

The 1,4-diazatriphenylene (1,4-DAT) belongs to the particular family of aza-aromatics

containing the pyrazine ring in its molecular framework. These molecules are reported in literature as systems showing unusual behavior in the excited states [1-3]. Contrary to isomeric structures, the basicity of both nitrogen atoms increases by several pK units in both lowest excited states, the S1 and T1. This unusual behavior was interpreted as a result of the distortion of the pyrazine ring upon excitation, and the change of hybridization of nitrogen atom from sp2

towards sp3, but a detailed nature of the distortion remained not clear.

Here, we attempt to ”translate” the experi-ence collected from a condensed phase to the experimental conditions of the molecule cooled and isolated in a molecular jet. The laser induced fluorescence excitation (LIF(E)) and dispersed fluorescence (DF) spectra of 1,4-DAT isolated in supersonic molecular jets and its 1:1 complexes with H2O and CH3OH are reported and analyzed with the help of TDDFT calculations. The symptoms of the distortion of the S1 excited molecule were read out from experiments. The nature of distortion, the boat type shape of pyrazine ring, is supported by calculations. It is also shown that the interaction with protic agents enhances the fluorescence efficiency by more than one order of magnitude, as an effect of inversion between (n,π*) and (π,π*) states.

[1] Z. R. Grabowski, A. Grabowska, Z. Phys. Chem. 101, 197 (1976). [2] A. Grabowska, B. Pakuła, J. Sepioł, Nouv. J. Chim. 3, 287 (1979). [3] N. Kanamaru, E. C. Lim, J. Chem. Phys. 62, 3252 (1975).

28620 28635 28725 28740

Methanol pressure: 0.06 kPa 0.006 kPa

Wavenumbers (cm -1)

Flu

ores

cenc

ein

tens

.

Fig. 1. The intensity changes of 0-0 transitions of LIF(E) spectra of bare 1,4-DAT and its 1:1 complexes with

methanol.

Posters


Solvent-induced changes in photostability

of 2-(1H-indole-2-yl)-[1,5]naphthyridine

Golec B.,1 Thummel, R.P.,2 Waluk J.1

1 Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzka 44, 01-224 Warsaw,

Poland; 2 University of Houston, Houston, TX 77204-5003, USA [email protected]

Bifunctional hydrogen bond donor/acceptor molecules often exhibit completely different pho-tophysical behavior in protic and aprotic solvents.1 Formation of multiple hydrogen bonds with, e.g., water or alcohols may lead to enhanced internal conversion; as a result, triplet formation efficiency can be reduced. This, in turn, could influence the photostability, provided that photo-destruction mainly occurs from the triplet state. In order to check this hypothesis, we have inves-tigated changes in photostability caused by interaction with aprotic and protic solvents for 2-(1H-indole-2-yl)-[1,5]naphthyridine, a molecule with hydrogen bond accepting and donating func-tionalities. The photostability of 2-(1H-indole-2-yl)-[1,5]naphthyridine in acetonitrile and alcohols was studied in the regime of 365 nm irradiation. The photodegradation process was monitored by UV spectroscopy. Large difference in photostability in the two solvents was observed: the molecule is much more stable in alcohol. Also the photochemical processes involved in photo-degradation seem to be different, as evidenced by the spectra of the photoproduct(s) measured for each solvent.

N

N

N

H

Fig. 1 The structure of the 2-(1H-indole-2-yl)-[1,5]naphthyridine

[1] J.Waluk, Acc. Chem. Res. 36, 832 (2003)

Posters


The usefulness of spectroscopic methods for assessi ng

color stability of dental materials

Krawczyk A.1, Lesiński Ł.1, Mazur-Koczorowska A.2, Sikorska E.3, Sikorski M.1

1 Faculty of Chemistry, A. Mickiewicz University, Umultowska 89b, 61-614 Poznań, Poland,

[email protected] 2 Medical Faculty II, Poznań University of Medical Science, Bukowska 70, 60-812 Poznań,

Poland 3 Faculty of Commodity Science, The Poznań University of Economics, al. Niepodległości 10,

60-967 Poznań, Poland

This work was motivated by the necessity to evaluate the color and luminescence changes of dental composites caused by staining drinks. We investigated the Filtec Z250 material after its polishing treatment. Coffee, red wine and distilled water were employed as the staining drinks. Prior to each staining test the initial sample color was measured. Next, ,the samples of Filtec material were immersed in 40 ml of staining liquids and stored there at 37°C for 0.5 h, 1.5 h, 3.0 h, 6.0 h, 12 h, 24 h, 48 h, 70 h and 116 h. After each of the time intervals, the samples were washed and their color was determined. Both surfaces of the samples were examined. The luminescence measurements were performed before the immersion into staining liquids and after 116 h of storage in a selected liquid. The luminescence spectra and contour maps were measured on a Fluorolog 3-11 Spex spectrometer (Jobin-Yvon). Reflectance spectra were measured using a Specord M-42 spectrophotometer, whereas color measurements were made using a Konica Minolta CM-2600d spectrocolorimeter. The color changes were examined by the colorimetric method using the L, a*, and b* parameters and the total color change ∆E in the CIELAB system. The A illuminant was used in all experiments.

A B

Contour maps presenting the intensity of luminescence of Filtec Z250 A2: A - clean samples, B - after 7 days of storage in wine.

[1] A. Mazur-Koczorowska, E. Sikorska, A. Krawczyk, I. V. Khmelinskii, M. Sikorski, J. Stopa, Polish J.

Environ. Stud. 24, 1A, 1329-1335 (2009) [2] A. Mazur-Koczorowska, E. Sikorska, A. Krawczyk, I. V. Khmelinskii, M. Sikorski, R. Koczorowski, J.

Stopa Dental Materials 24, 1329-1335 (2008) [3] M. Gawriołek, E. Sikorska, L.F.V. Ferreira, A.I. Costa, I. Khmelinskii, A. Krawczyk, M. Sikorski, R.

Koczorowski, Journal of Prosthodontics 21, 112-122 (2012) [4] M. Gawriołek, R. Koczorowski, I. Ferreira Machado, L.F.V. Ferreira, A. Krawczyk, E. Sikorska, M. Si-

korski, Dental Forum 2, XXXVII, 15-22 (2009)

Posters


Study of electronic properties of fullerene-thiophe ne dyads

Kornelia Lewandowska1,2, Agnieszka Podborska2 , Konrad Szaciłowski2

1 Polish Academy of Science, Institute of Molecular Physics, ul. Smoluchowskiego 17, 60-179

Poznań, Poland 2 AGH University of Science and Technology, Faculty of Non-Ferrous Metals, al. A. Mickiewicza

30, 30-059 Kraków, Poland

Organic thin films with semiconducting properties are currently investigated intensively be-cause of their potential application in solar cells, gas sensors, electroluminescent and electronic devices. The donor-acceptor semiconductor molecules are increasingly important for applica-tions in optical and electronic devices such as diodes or transistors [1-4]. The characteristics of organic electronic device are strongly dependent on the injection barrier height, which is domi-nated by energy level alignment right at the interface. Thus, it is important to obtain information about energy level alignment at the metal/organic semiconductor interface. It is very well-known that the adjustment of equilibrium conditions is connected with a charge transfer across the interface, which leads to interfacial electric dipole layers (∆) and a band bending in semiconduc-tor. In the case of metal/organic semiconductor interface the alignment of the Fermi level and formation of ∆ were also observed.

Fig. 1. Optimized geometries of the investigated molecules (1TF-C60, 2TF-C60 and 3TF-C60). Theory level:

B3LYP/6-31G(d,p). In our study we focused on fullerene-thiophene systems (Fig.1). These materials show very

interesting spectral and photoelectrochemical properties, which are depending on the number of thiophene rings. Therefore they are promising materials for the construction of molecular organ-ic LEDs.

The results indicate that the fullerene-thiophene systems could be in the future used to build logic circuits, bipolar transistors, or demultiplexers.

The paper was supported by the National Science Centre, Poland within the post-doctoral internships pro-ject to be realized in the years 2012-2014 (grant 2012/04/S/ST5/00071; K.L.). The authors thank Professor Kwang-Sup Lee (Daejeon, South Korea) for thiophene-fullerene dyads preparation. [1] C. W. Tang, Appl. Phys. Lett. 48, 183 (1986) [2] D. Wӧhrle, L. Kreienhoop, G. Schnurpfeil, J. Elbe, B. Tennigkeit, S. Hiller, D. Schlettwein, J. Mater. Chem. 5, 1819 (1995) [3] K.-Y. Law, Chem. Rev. 93, 449 (1993) [4] R. H. Friend et al., Handbook of Nanophysics: Nanotubes and Nanowires (Dimitrakopoulos, Malenfant, 2002)

Posters


Applications of fluorescent sensor based on

1H-pyrazolo[3,4- b]quinoline in analytical chemistry

Marek Maca, Tomasz Uchacza,b, Andrzej Danelb, Hanna Musiolika

a) Faculty of Chemistry, Jagiellonian University, 30-060 Krakow, Ingardena 3; b) Department of Chemistry, University of Agriculture, 31-149 Kraków, Balicka 122, Poland

Fluorescent dye 2-[(2-Hydroxyethyl)-(1,3-diphenyl-1H-pyrazolo[3,4-b]quinolin-6-ylmethyl)-amino]ethanol (LL1) was examined for its efficiency in the detection of small inorganic cations (lithium, sodium, barium, calcium, magnesium, cadmium, lead and zinc). The dye was synthesi-zed in the laboratory and investigated by means of both, steady-state and time-resolved fluore-scence techniques. This compound acts as a fluorescent sensor suitable for detection of small inorganic cations (lithium, sodium, barium, calcium, magnesium, cadmium, lead and zinc) in strongly polar solvent (acetonitrile). Mechanism which allows to apply this compound as a sen-sor is an electron transfer from the electro-donative part (receptor) of the molecule to the accep-tor part (fluorophore). The process can be retarded upon complexation of the receptor moiety by inorganic cations. Quite a high sensitivity but poor selectivity of the aminoalcohol-containing indicator towards the two-valued cations has been observed. However, upon addition of some amounts of water the selectivity of this sensor has been enhanced (especially towards lead cation). In addition, the preliminary results on application of this indicator for analytical investi-gations were discussed. An example of the fluorimetric titration of Pb(ClO4)2 by terabutyl chlo-ride in the presence of LL1 is presented below.

-0.02 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14

0

1000

2000

3000

4000

5000

6000

-0,02 0,00 0,02 0,04 0,06 0,08 0,10 0,12 0,14-5x105

-4x105

-3x105

-2x105

-1x105

0

dIfl/d

VTB

AC

l

VTBACl

/ml

Flu

ores

cenc

e in

tens

ity /a

.u.

VTBACl

/ml

References:

M. Mac, T. Uchacz, A. Danel, H. Musiolik, Applications of fluorescent sensor based on 1H-pyrazolo[3,4-b]quinoline in analytical chemistry. J. Fluoresc. (in press).

Posters


O

N

N

O

N

O

N

N

O

N N

O

N O

O

O

DMAF

6DMAPd Pd MGLBCVLB

+ +

Fig.1 Structures of CVLB and MGLB and their structural subunits

Solvent effect on dual fluorescence of

bridged triarylmethane lactones

Majka A.,1 Karolak-Solarska E.,1 Nowacki J.2 Karpiuk J.1

1 Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01 – 224 Warsaw, [email protected]


Bridging two dimethylaniline moieties in crystal violet lactone (CVL) or malachite green lac-tone (MGL) results in formation of spirocyclic molecules composed of two perpendicularly aligned chromophore moieties: 3,6-bis(dimethylamino)fluorene (DMAF) and 6-dimethylamino-

phthalide (6-DMAPd ) in CVLB or phthalide (Pd) in MGLB . DMAF and 6-DMAPd have nearly degen-erate S1 states, whereas the S1 state of Pd lies much higher in energy. Although the subunits are separated by an sp3 carbon link, the absorption spectra of CVLB and MGLB in low energy region indicate significant ground-state spiroconjugation. Detailed photo-physical study has shown that dual

fluorescence of CVLB in more polar solvents comes from a locally excited state localised on DMAF or 6-DMAPd subunit, depending on solvent polarity, and from a highly polar CT state formed after electron transfer from DMAF to 6-DMAPd moiety [1,2]. Fluorescence is only a minor relaxation mechanism, and the dominant deactivation pathway in CVLB is ultrafast disso-ciation of the C–O bond in lactone ring.

Unlike its non-bridged precursor MGL, in low polar cyclohexane MGLB displays very weak fluorescence from the S1 state localised on DMAF, similarly as in CVLB . Both the spectra, and the fluorescence quantum yields (Φfl ~10-4) indicate similar deactivation mechanism in MGLB and CVLB . Dual fluorescence observed in ethyl ether and ascribed to LE and CT states trans-forms into a single band in polar butyronitrile. An excitation-wavelength dependent short-wave fluorescence band observed in acetonitrile is tentatively ascribed to products of ultrafast excited state dissociation.

A detailed study of MGLB photophysics as a function of solvent polarity, proticity and tem-perature will be presented and compared with those of CVLB.

[1] E. Karolak-Solarska, Photoinduced electron transfer in triarylmethane lactones. Photophysics-structure

relationship, doctoral dissertation, Institute of Physical Chemistry PAS, Warsaw, 2013. [2] J. Karpiuk, E. Karolak-Solarska, P. Fita, M. Kijak, A. Majka, J. Nowacki, manuscript in preparation.

Posters


Chemically Oxidized Water

Marzena Marchaj, Sylwia Freza, Olimpia Rybacka, Piotr Skurski

Department of Chemistry, University of Gdańsk, Sobieskiego 18, 80-952 Gdańsk, Poland

Corresponding Author e-mail: [email protected]

The ability of ionizing water molecules by chosen strong oxidizing agents of superhalogen nature is demonstrated. It is shown that two selected superhalogens, BF4 and AlF4 (whose corresponding daughter anions BF4

– and AlF4– are known to strongly bind an excess electron),

might be employed to ionize single water molecule and small water clusters ((H2O)n, n=2-4) which results in forming [(H2O)n]

+[BF4]– and [(H2O)n]

+[AlF4]– stable species (n=1-4). The

[(H2O)n]+[BF4]

– and [(H2O)n]+[AlF4]

– molecules are characterized by large values of binding (in-teraction) energy (28-73 kcal/mol) and substantial charge flow (0.5-0.8 au) between the compo-nents which confirms their ionic nature.

Posters


Photophysical properties of selected porphycene der ivatives

substituted at meso positions with phenyl groups

Masiera N., Listkowski A., Kijak M., Waluk J.

Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44,01-224 Warsaw [email protected]

Porphycene derivatives are very interesting objects of studies due to their biochemical

and optical properties. Meso-substituted compounds of this group are especially relevant. It was reported that 9,10,19,20-tetraalkylporphycenes may reveal different tautomeric forms: cis and trans. Transitions between these two forms, involving hydrogen transfer, occur in solutions of the compounds in organic solvents [1].

The aim of the present study was to understand the relationship between the structure and photo-physical properties of the porphycene derivatives substituted at meso positions with aryl groups. The investigated compounds are presented in Fig. 1. The studies included determination of molar absorption coefficients and quantum yields, analysis of absorption and fluorescence spectra, estimation of the kinetic parameters of fluorescence decay, and quantum-chemical calculations.

Time-correlated single photon counting experi-ments showed mono-exponential decay of fluores-cence of 1 and 2 in both polar and nonpolar sol-vents. The values of time constants of fluorescence decay and fluorescence quantum yields determined for 1 were of the order expected for porphycenes in organic solvents. An interesting variation was observed for compound 2. Fluorescence decays shorten drastically with respect to 1, and quantum yields of fluorescence of the order of 1% indicate the existence of a rapid S1 deactivation channel, which was confirmed in a range of different sol-vents. Fluorescence decay of 3 is mono-exponential only in the case of a nonpolar solvent, whereas in polar environment the compound reveals double-exponential kinetics of singlet excited state decay. This suggests the occurrence of two different forms of 3, with molar ratio dependent on the solvent, which is also confirmed by the fluorescence quan-tum yields measurements. Moreover, the analysis of the collected data shows that the lifetime of one form is three times shorter than that of the other. The experimental findings will be correlated with the results of quantum-chemical calculations. [1] M. Gil, J. Dobkowski, G. Wiosna-Sałyga, N. Urbańska, P. Fita, C. Radzewicz, M. Pietraszkiewicz, P. Borowicz, D. Marks, M. Glasbeek, J. Waluk, J. Am. Chem. Soc. 132, 13472 (2010)

NN

NNH H

NN

NNH H

NN

NNH H

1

2

3

Fig.1 Structures of the studied compounds

Posters


Stability of platinum and palladium complexes with cyano- and

imidazolylcobalamin

Gabriela Mazur, Łukasz Orzeł, GraŜyna Stochel

Faculty of Chemistry, Jagiellonian University, [email protected]

Diagnosis and treatment of cancer are fundamental challenges facing modern medi-cine and pharmacology. Recently, special emphasis is placed on the development of innovative and non-invasive techniques for efficient implementation of diagnostic/therapeutic compounds into cells. Therapeutic complexes for their medical applications need to be connected with spe-cific carriers in order to accumulate selectively in diseased cells. Appropriate carrier should be: soluble in body fluids, recognized by receptors of membrane channels, well-absorbable by the cells in their pathological conditions, such as cancer or microbial infections. These are often compounds of natural origin, endogenous substances or their derivatives. The search for appropriate thera-peutic compounds and the appropriate carriers focus-es both on the mechanisms of transport across mem-branes and activity of the substances transported - in the form linked to a carrier or released on target.

The research is focused on the synthesis and physicochemical (including photochemical) char-acteristic of platinum/palladium complexes with cobal-amin. Based on the literature on this problem it can be stated that using cobalamin (and its derivatives) as a "Trojan Horse" - a carrier should cause high accumu-lation of therapeutic agents in diseased cells.[1] The experience of the author submitting this proposal indi-cates that the most promising way to attach a thera-peutic agent to cobalamin through the N-donor bridg-ing ligand, such as imidazolyl or cyano group.

Chemotherapy based on platinum complexes[2] also implies the need for the con-trolled release of therapeutic complex in target cells This means that the strength of the bond between the d-electron metal and its carrier-compound has to be adapted to the conditions prevailing/possible to provide in the cell. Degradation of platinum/ruthenium/palladium - carrier complex can be controlled by differences in pH or light delivered. Fitting the binding energy of the low energy range within the visible and near-infrared (NIR) light wavelengths seems to be particularly beneficial. Experiments of controlled degradation of the bond between d-electron metal and the carrier have been performed. In this way, the technique known as PDT (Photody-namic Therapy) can find an entirely new application of the “classic" chemotherapy.

[1] P. Ruiz-Sẚnchez, S. Mundwiler, B. Spingler, N. R. Buan, J. C. Escalante-Semerena, and R. Alberto, J. Biol. Chem. 13, 335-347 (2008)

[2] M. Holschbach, W. Hamkens, A. Steinbach, K. Hamacher and G. Stıcklin, Appl. Radiat.Isot. 48, 739-744 (1997)

Posters


Photoelectrochemical properties of BiVO 4

Mech J.1, Kwolek P. 1, Szaciłowski K.1,2



The main objective of the work is syn-

thesis and characterization of new optical active hybrid materials based on BiVO4 modified with organic compounds named alizarin and alizarin red S. This material reveals PEPS effect (Photoelectrochemical Photocurrent Switching), the phenomena which enables simple controlling of the direction of photocurrent, by changing one or more parameters: wavelength of inci-dent light, applied potential or concentra-tion of sacrificial electron or hole acceptor in surrounding electrolyte [1-3]. Modifica-tion of prepared semiconductor is realized by surface adsorption of organic molecules from aqueous (alizarin red S) or acetonitrile (alizarin) solutions. The research also includes the influence of morphology of

BiVO4 on photocurrent characteristics. N-type BiVO4 is obtained via microwave assisted hydro-thermal method. By changing the pressure in the autoclave chamber during the synthesis it is possible to modify the shape and dimension of crystallites. This technique leads to clino-bisvanite structure. The character of photocurrent in such material changes significantly with the change of oxygen concentration in electrolyte. In negative potential region strong cathodic pho-tocurrent can be observed (fig.1). What is interesting the maximum of cathodic photocurrents occurs at different wavelength than maximum of anodic ones.

Project was funded by the National Science Center (grant 2011/03/N/ST5/04470) and by Malopolska Scholarship Found for PhD students (grant ZS.4112-212/2010).

[1] Di Iorio, Y., et al., New J. Chem. 37, 969-976 (2013)

[2] Oszajca, M., et al., J. Phys. Chem. C 115, 12187-12195 (2011)

[3] Mech, J., et al., Aust. J. Chem. 63, 1330-1333 (2010)

Posters


Fig.1 Methylene Blue molecule

Photochemistry of Methylene Blue in water

Domcke W.2, Morawski O.1, Sobolewski A.1

1 Institute of Physics, Polish Academy of Sciences, [email protected]

2 Department of Theoretical Chemistry, Munich Technical University

Methylene blue (MB, figure 1) is a cationic dye widely used in biology and medicine [1], mainly for its known antibacterial activity [2]. The dye is sensitive to changes in the polarity of its sur-

roundings [3], has reversible redox properties [4] and is useful as redox indicator [5]. MB is also used for determination of glucose and O2 [6,7] in vivo. Our work on this popular molecular system aims to investigation of its photo-chemistry in water and to identifi-cation of the photoproducts. This is done by comparing results of spectroscopic measurements with quantum-chemical predictions.

Our results point to the main conclusion that photo-irradiation of MB in aqueous solution results

in creation of hydroxyl radicals due to photo-catalytic water splitting. The mechanism of this reaction is similar to that previously proposed for oxotitanium porphiryn [8] and pyridine [9], with the nitrogen atom as reaction centre. The process can be written as

MB+ + H2O + hν -> MBH+ + OH•

In parallel to water splitting the photo-bleaching of MB occurs. The process depends on pH; it is inhibited in acidic solution, but it is amplified in basic solution due to the presence of OH-. In neat water three photoproducts have been spectroscopically determined; one of them as a transient species. We associate formation of photoproducts with reduction of MB+.

[1] J. V. Frangioni et al., Surgery 148, 78 (2010) [2] I. P. Parkin et al., J. Mater. Chem. 19, 6167 (2009) [3] T. Handa et al., Bull. Chem. Soc. Japan 56, 2548 (1983) [4] S.K. Lee, A. Mills, J. Chem. Soc., Chem. Commun. 2366, (2003) [5] N. Tognalli, A. Fainstein, C. Vericat, M. Vela, R. Salvarezza, J. Phys. Chem. C 112, 3741 (2008) [6] G.P. Gorbenko, Y.A. Domanov, J. Biol. Phys. Chem. 5, 13 (2005) [7] L. Adamcikova, K. Pavlikova, P. Sevcik, Int. J. Chem. Kinetics 31, 463 (1999) [8] A. L. Sobolewski, W. Domcke, Phys. Chem. Chem. Phys. 14, 12807 (2012) [9] X. Liu, A. L. Sobolewski, W. Domcke, Phys. Chem. Chem. Phys. 15, 5957 (2013)

Posters


Stability and photocatalytic activity of titanium d ioxide colloids

stabilized with polymers

Pacia M., Macyk W.

Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060, Kraków, Poland mails: [email protected], [email protected]

Titanium dioxide is one of the most commonly investigated photocatalysts due to its high

photoactivity. Neat TiO2 exhibits a photocatalytic activity only upon UV irradiation. Therefore much effort has been put to develop a method to extend TiO2 absorption band to visible range. This is mostly done by doping or by binding various complexes at titanium dioxide surface [1]. Nanocrystalline TiO2 colloids face other problems, related to aggregation of particles in aqueous media at neutral pH. The lack of stability of TiO2 colloids results in decreasing absolute values of zeta potential (which represents a surface charge) upon neutralization of acidic solutions [2-4]. A decrease of the surface charge weakens the electrostatic repulsion forces in the system, leading to aggregation of particles.

The aim of this work was to achieve a stability of nanocrystalline titanium dioxide aqueous colloids in a wide range of pH. The influence of water soluble polymers on stability of nanoparticles in neutral solutions and on physicochemical properties of obtained colloids were studied. Photoactivity of the materials, in particular oxygen reduction and water oxidation preceding a formation of various reactive oxygen species, was tested. Attempts to photosensitize stable systems to visible light were also undertaken.

Five different substances (Figure) at various concentrations were tested as stabilizers. Only one of the obtained colloids (stabilized with TWEEN ® 80) remained stable during irradiation, and appeared stable in a wide range of pH. Photocatalytic activity tests towards degradation of organic dyes (methylene orange, azure B) upon UV light irradiation were carried out. 2,3-naphthalenediol was used to form coloured titanium(IV) charge transfer complexes, sensitizing TiO2. The photosensitized system showed a surprisingly high activity, as tested in the process of azure B degradation.

Acknowledgements

The work was done within the „Activation of small molecules in photocatalytic systems” pro-ject, realized within the TEAM programme of the Foundation for Polish Science, co-financed by European Union, Regional Development Fund.

[1] Macyk, W.; Szaciłowski, K.; Stochel, G.; Buchalska, M.; Kuncewicz, J.; Łabuz, P., Coord. Chem. Rev. 254, 2687-2701 (2010).

[2] Mandzy, N.; Grulke, E.; Druffel, T., Powder Technol. 160, 121-126 (2005). [3] Fazio, S.; Guzmán, J.; Colomer, M. T.; Salomoni, A.; Moreno, R., J. Eur. Ceram. Soc. 28, 2171-

2176 (2008). [4] Liu, X.; Chen, G.; Su, C., J. Colloid Interface Sci. 363, 84-91 (2011).

a)

b)

c)

Figure. Structures of used stabilizers: a) PEG1500, 4000 and 6000, b) SDS, c) TWEEN ® 80.

Posters


12000 16000 20000 24000 280000.0

0.2

0.4

0.6

0.8

1.0

1.2

fluor

esce

nce

inte

nsity

[a.

u.]

wavenumber [cm-1]

10200 cm-1

ACN BTN BA EE HEX

Fig.1 Solvent effect on fluorescence spectrum of MGLAC6.

Synthesis and photoinduced electron transfer in

bridged diarylmethane lactones

Piechowska J.,1 Nowacki J.,2 Karpiuk J.1

1 Institute of Physical Chemistry, Polish Academy of Sciences, [email protected] 2 Institute of Physics, Polish Academy of Sciences

Electron donor-acceptor (D–A) systems with an sp3 car-

bon link between D and A have received relatively little attention [1-3], though they provide the optimum geometries for fast electron transfer (ET), as exemplified by malachite green lactone (MGL) [2]. Simplifying MGL structure to a diarylmethane dyad (MGLA) results also in charge separa-

tion with formation of a highly polar 1CT state [3]. The photoinduced charge separation (CS) and recombination (CR) in MGLA prove that (i) the sp3 carbon link coupled with C–O bond is a very efficient link in ultrafast intramolecular electronic communication, and that (ii) the photoinduced CS in triarylmethane lactones involves essentially only one electron-donating group.

Br

O

N

O

N n-BuLi, THF

N

OH

O

N

N

O

O

0.6 N HCl

48%

MGLAC6 To clarify the role of the D–A ge-

ometry in photoinduced ET process across the sp3 link a new spirocyclic derivative of MGLA, MGLAC6, has been synthesized and its photophysics compared with MGL and MGLA. The crucial synthetic step was nucleophilic addition of a lithium-organic com-pound to ketone to enable direct com-bination of two chromophores.

The photoinduced CS and CR pro-cesses in MGLAC6 show close analo-gy to MGLA. The fluorescence spec-trum of MGLAC6 is more sensitive to

solvent polarity, with solvatochromic shift between hexane and acetonitrile of 10200 cm-1. The value is equal to that reported for fluoroprobe as the largest solvatochromic effect so far [5].

[1] C. A. van Walree, M. R. Roest, W. Schudeboom, L. W. Jenneskens, J. W. Verhoeven, J. M. Warman, H. Kooijman, A. L. Spek, J. Am. Chem. Soc. 118, 8395-8407 (1996).

[2] J. Karpiuk, Phys. Chem. Chem. Phys. 5 1078-1091 (2003). [3] J. Karpiuk, E. Karolak, J. Nowacki, Polish J. Chem., 82, 865-882 (2008). [4] T. Bizjak, J. Karpiuk, S. Lochbrunner, E. Riedle, J. Phys. Chem. A 108 10763-10769 (2004). [5] C. Reichardt, Chem. Rev., 94, 2319-2358 (1994).

MGLA MGL

N

O

O

N

O

O

N

Posters


450 500 550 600 650 700

pKa = 8.51

pKa* = 8.42 from fluorimetric titration

pKa* = 1.64 from Forster cycle

Rel

ativ

e In

tens

ity

λ / nm

pH 2.9 pH 4.3 pH 6.4 pH 6.9 pH 7.9 pH 8.9 pH 9.6 pH 10.2 pH 11.5 pH 12.9

Fig.1 Synchronous fluorescence spectra of the com-

pound at selected pH; offset – ∆λ = 60 nm)

Protonated form (hemicyjanine)

benzenoid structure

hv

quinoid structure

NOH

CH2BrOCH3

X_

NOH

CH2BrOCH3

X_

NOH

CH2BrOCH3

X_

hv

*benzenoid structure

proticsolvents

aproticsolvents

*

Fig.2 Ground and excited-state structures of protonated form

of the compound in protic and polar, aprotic solvents.

Influence of pH and solvents polarities on photophy sical proper-ties of N-(4-bromobenzyl) substituted hydroxystilba zolium hemi-

and merocyanine.

Prukała D.1, Prukała W.1, Gierszewski M.1, Sikorski M.1

Faculty of Chemistry, Adam Mickiewicz University in Poznań, [email protected]

Photophysical properties of (E)-1-(4-bromobenzyl)-4-(4-hydroxy-3-methoxystyryl) pyridinium

bromide at different pH existing in equilib-rium of its protonated (hemicyanine) and deprotonated (merocyanine) forms were characterized by UV-Vis spectroscopy, including absorption, emission and syn-chronous spectra (Fig. 1).

The time–resolved measured indicate that fluorescence lifetimes of the two forms are very short (35 ps and 16 ps, respectively). This implies that each of these forms after excitation emits very quickly or (predominantly) relaxes back to the ground state, before any excited-state acid-base equilibrium may be estab-lished. Therefore, the Förster cycle used

in such system is unable to reproduce the apparent pKa*.

Solvatochromism of protonated and deprotonated forms of investigated compound in polar and protic solvents was ana-lyzed using the four-parameter Catalán solvent scale and the ∆f scale. This analysis indicates that the structure of both forms in protic solvents is benzenoid-like (zwitterionic for deproto-nated form) in their emissive state. However, in aprotic polar solvents the weight of quinoid structure of their emissive state is favored (Fig. 2). Importantly, the Catalán scale shows a strong influence of non-specific

solute-solvent interactions on the absorption and emission properties of both forms.

[1] D. Prukała, W. Prukała, M. Gierszewski, J. Karolczak, I.V. Khmelinskii, and M. Sikorski, Photochem. Photobiol. Sci.11, 1454 (2012) [2] Catalán, J. J. Phys. Chem. B, 113, 5951 (2009) [3] J. R. Lakowicz, Principles of Fluorescence Spectroscopy, (Springer Science, New York, 1999)

Posters


Theoretical study on photophysics of PT-based molec ular photo-

switches

Rode M. F. and Sobolewski A. L.

Institute of Physics, Polish Academy of Sciences, [email protected]

Molecular switches which enable the storage of information on a molecular level may have application in nanotechnology, biomedicine, and computer chip design. The molecular system which can serve as a molecular switch must posses two stable forms which may be switched by an electric filed, chemical reaction or by an optical excitation. In our investigation we are searching for molecular photo-switches which operate on the Ex-cited State Intramolecular Proton Transfer (ESIPT) phenomenon (see Fig. 1) [1-4]. The switch-ing process induced by an optical excitation involves the long-distance transfer of a proton be-tween the two remote proton-donnating/accepting sites: “X” and “Z” both located within the “molecular frame” unit (F).

a) Twist-assisted ESIPT (TPT)

b) Double ESIPT (DPT) Fig. 1

In this communication the two photoswitching mechanisms are compared: the first one (1a) based on Twist-assisted ESIPT process (TPT) [1-3], and the second one (1b) based on the Double-ESIPT reaction (DPT) [4]. Both mechanisms are mediated by the two different functional units: TPT by the “proton crane” moiety (C) (1a) and DPT by the “proton-transmitter” unit (T) (1b). The mechanism of the two classes of photoswitches: TPT and DPT will be exemplified by the study of photophysics of two isolated model molecules: 7-hydroxy-8-carbaldehyde-quinoline (1a) and 3-hydroxy picolinic acid (1b), respectively. Our study shows that the energetical landscape of the ground and the lowest excited states can effectively be modulated by chemical substitutions to the parental molecules, (1a) or (1b). [1] A. L. Sobolewski, Phys. Chem. Chem. Phys., 10, 1243 (2008). [2] L. Lapinski, M. J. Nowak, J. Nowacki, M. F. Rode and A. L. Sobolewski, ChemPhysChem, 10, 2290 (2009). [3] M. F. Rode, and A. L. Sobolewski, J. Phys. Chem, A, 114, 11879 (2010). [4] M. F. Rode, and A. L. Sobolewski, Chem. Phys. 409, 41 (2012).

hν2

F

C Y

H X Z

Y

H Z X

hν1

H2

F

X Z

T Y W

H1 H2

X Z

Y W

H1 hν2

hν1

Posters


pKa = 3.8

pK* ~ -2

hνννν

*

H

H

*- H+

H+

NH

N

N

N

N

NH2

NH2N

NH

N

N

N

NH2

NH2

NH2

N

NH2 N N

NH

N

N

NH

N

N

N

NH2

NH2

+

+

Scheme 1. Phototautomerism “via the cation” in 2-amino-8-

azaadenine (see ref. [4]).

Excited-state proton transfer in nucleobase and nuc leoside ana-

logs: an update

Wierzchowski J.

Department of Biophysics, University of Warmia & Masuria, Olsztyn, [email protected]

Intermolecular excited-state proton-transfer (ESPT) is a commonplace phenomenon in het-erocyclics [1], and in it was also observed in fluorescent nucleobase an/or nucleoside ana-

logues [2, 3, 4, 5, 6]. In the pre-sent work, several new examples of ESPT in this class of com-pounds will be presented together with a brief recapitulation of the previously published data.

The nucleobases, nucleosides and their analogues contain many basicity/acidity centres and there-fore their ESPT behaviour may be complex. Typical approach to solve this problem is by analysis of the alkyl derivatives, in which the possibility of the ESPT is reduced.

Of particular interest are ex-amples of “phototautomerisation

via the cation”, observed in several systems which in the neutral media do not undergo ESPT [2, 4], as illustrated in the Scheme 1. Protonation of the molecule in the ground state facilitates two-step phototautomerism in several systems [2, 4, 5].

Fluorescence of the nucleobase and nucleoside analogues undergoing ESPT is usually sol-vent-, isotope- and buffer-ion sensitive, and in some systems the ESPT can be promoted by environmental factors, e. g., the presence of buffer ions. This sensitivity to the microenviron-ment parameters makes the ESPT systems potentially useful for biological applications.

[1] B. Valeur, Molecular Fluorescence (Wiley-VCH, Weinheim, 2002) [2] J. Wierzchowski, Curr. Top. Biophys. On-line. 33, 9 (1986). (http://www.staff.amu.edu.pl/~ctbo/issue33/v33_9.pdf) [3] J. Wierzchowski et al., J. Photochem. Photobiol. A., 237, 64 (2012) [4] J. Wierzchowski et al., J. Photochem. Photobiol. A., 265, 49 (2013). [5] T. Kitamura et al., Spectrochim. Acta Part A, 62, 1157 (2005). [6] A. Dumas & N.W. Ludtke, Chemistry – A European Journal 18, 245 (2012).

Posters


New benzotriazole based polymers as potential act ive materials

in organic light emitting devices.

Wiosna-Sałyga G.1*, Ulański J.1, Grimsdale A. C.2

1 Department of Molecular Physics, Lodz University of Technology, gabriela.wiosna-

[email protected] 2 School of Materials Science and Engineering, Nanyang Technological University

Benzotriazole based polymers have been recently attracting attention as materials for use in

organic photovoltaics (OPV), organic electrochromics (OEC) and organic light emitting diodes (OLED). New materials, donor-acceptor copolymers, containing a benzotriazole and fluorene moieties (Fig. 1) [1] have been considered as an active layer in light emitting devices.

Preliminary studies of the optical and electro-optical properties of luminescent polymers, in-volving factors that could increase photoluminescence quantum yield efficiency, were per-formed. This is one of the first steps on the road to developing efficient devices. Attempts have been made to describe the relationships between chemical structure, molecular packing and properties.

NNN

NN N

S S

C8H17

C8H17

C12H25

C10H21

C10H21 C12H25

NNN

NN N

S S

C8H17

C8H17

C10H21 C12H25

C12H25C10H21

BBTa16F BBTa15F

Fig. 1 Molecular structures of investigated copolymers.

[1] T. L. D. Tam, W. Ye, H. H. R. Tan, F. Zhou, H. Su, S. G. Mhaisalkar, A. C. Grimsdale, J.Org.Chem. 77, 10035 (2012) *on leave from Institute of Physical Chemistry, Polish Academy of Sciences

Posters


Fig.1 The scheme of the experimental setup

Fig.2 The kinetic curve showing oscillation in the gold(III) chloride complex ions concentration during prolonged illumination. Exper-imental conditions: [CH3OH]0 = 6.2 M, [Au(III)]0 = 5•10−4 M, pH = 2, irradiation at 405 nm with 80% of the maximal light intensity.

Oscillation of gold(III) complex chloride ions conc entration during

photoreduction with methanol: kinetic study.

Wojnicki M.1, Kwolek P.1

1 AGH University of Science and Technology, [email protected]

It is well known, that molecules in their excited states undergo reduction or oxidation much easier than in their ground states[1]. Therefore, there is a possibility of gold(III) complex ions photoreduction using reductant, that is not able to reduce AuCl4

− in the absence of light (or the reaction rate is very low).

The aim of the studies was the investigation of the mechanism of gold(III) chloride complex ions reduction by methanol from UV-Vis illuminated aqueous solutions. It was shown, that gold(III) chloride complex ions are reduced by methanol only at the presence of the light. The illumination must be carried out in the range of AuCl4

− ions light absorption. The reduction is first order in respect to both methanol initial concentration and light intensity, whereas the influence of gold(III) complex chloride ions initial concentration was more complex. The solid phase precipitation occurs via the disproportionation of presumably AuCl2

− ions. Illumination during the disproportionation process resulted in oscillation of gold(III) complex chloride ions concentration (see fig. 2).

In the inset (fig. 2) the UV – Vis spectrum is shown. Peaks at 223 nm and 314 nm corresponds to the AuCl4

− reformation, ab-sorbance at 610 nm origins from the surface plasmon resonance and indicates the precipitation of the solid phase.

Funding Sources

Financial support from POIG (Europen Grant No. POIG 0.1.01.02-00-015/09-00) and AGH University of Science and Technology (contract no. 11.11.180.509) is gratefully acknowledged.

[1] Memming, R. Semiconductor electrochemistry, first ed.; Wiley-VCH: Weinheim, 2001.

Posters


Investigations on the photoactivity of the Au@TiO 2

Woyciechowska K., Dąbrowski D., Łabuz P., Stochel G., Macyk W.

Coordination and Bioinorganic Physicochemistry Group, Faculty of Chemistry, Jagiellonian

University, [email protected]

In antiquity colloidal gold was used to make ruby glass and for coloring ceramics, but the phenomena behind this beautiful color was not understood. Studies of the gold nanoparticles started in XVII century. But only in 1818 it was suggested that the color of colloidal gold depends on particle size [1]. Now we know that freely mobile electrons of gold particles show a characteristic collective oscillation frequency of the plasma resonance, giving rise to the so-called plasmon resonance band observed near 530 nm [2]. This effect may be utilized to transform the light energy into chemical energy, for example by photosensitization of TiO2. TiO2 is a commonly used photo-catalyst because of its stability in UV light and water [3]. Unfortunately, the need to use UV light as an excitation source restricts its technological utility for limited applications. This is the reason for intensive studies that are carried out to make TiO2 active in visible light and deposition of gold nanoparticles at its surface is one of the possible solutions. It was also shown that for photosensitization of TiO2 gold in other forms can be used, e.g. gold ions Au3+ [4].

The aims of this studies was the determination of gold nanoparticles and AuCl4- influence on

photocatalytic activity of titanium dioxide. The gold nanoaprticles modified TiO2 was prepared using a water-in-oil microemulsion system of water/Triton X-100/cyclohexane [5]. The obtained materials were characterised by diffuse reflectance spectroscopy in UV-Vis range and X-ray powder diffraction analysis (XRD). The photocatalitic activity of such materials under visible light irradiation (> 435 nm) was investigated by measuring the decomposition rate of phenol and the efficiency of 2-hdroxyterephthalic acid formation in an aqueous solution and compared with activity of gold nanoparicles alone and TiO2 in presence of HAuCl4. The gold nanoaprticles modified TiO2 and TiO2 in presence of HAuCl4 were also tested in photoelectrochemical measurements.

[1] M.C. Daniel, D. Astruc, Chem. Rev. 104, 293 (2004) [2] V. Kontturi, P. Silfsten, J. Raty, K.E. Peiponen, Plasmonics 6, 345 (2011) [3] R.S. Sonawane, M.K. Dongare, J. Mol. Catal. A: Chem. 243, 68 (2006) [4] F.B. Li, X.Z. Li, Appl. Catal., A, 228 15 (2002) [5] A. Zielinska-Jurek, E. Kowalska, J. W. Sobczak, W. Lisowski, B. Ohtani, A. Zaleska, Appl. Catal., B

101 504 (2011)

Notes


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