Photoactivated Silicon–Oxygen and Silicon–Nitrogen ...
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doi.org/10.26434/chemrxiv.11441625.v1
Photoactivated Silicon–Oxygen and Silicon–NitrogenHeterodehydrocoupling with a Commercially Available Iron CompoundRory Waterman, Matthew B. Reuter
Submitted date: 23/12/2019 • Posted date: 24/12/2019Licence: CC BY-NC-ND 4.0Citation information: Waterman, Rory; Reuter, Matthew B. (2019): Photoactivated Silicon–Oxygen andSilicon–Nitrogen Heterodehydrocoupling with a Commercially Available Iron Compound. ChemRxiv. Preprint.https://doi.org/10.26434/chemrxiv.11441625.v1
Si–O and Si–N heterodehydrocoupling catalyzed by the commercially available iron dimer (1) underphotochemical conditions is reported. Mechanistic study reveals that the most immediate hurdle in thecatalysis is the poor activation of 1, demonstrating the necessity to fully activate the catalyst to realize thepotential of iron in this reactivity.
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ARTICLE
Received 00th January 20xx,
Accepted 00th January 20xx
DOI: 10.1039/x0xx00000x Photoactivated Silicon–Oxygen and Silicon–Nitrogen Heterodehydrocoupling with a Commercially Available Iron Compound
Matthew B. Reuter, Michael P. Cibuzar, James Hammerton, and Rory Waterman*
Silicon–oxygen and silicon–nitrogen heterodehydrocoupling catalyzed by the commercially available cyclopentadienyl
dicarbonyl iron dimer [CpFe(CO)2]2 (1) under photochemical conditions is reported. Reactions between alcohols and PhSiH3
with catalytic 1 under visible-light irradiation produced silyl ethers quantitively. Reactions between either secondary or
tertiary silanes and alcohols also produced silyl ethers, however, these reactions were marked by their slower longer
reaction times and lower conversions. Reactions of either production from either primary or secondary amines and silanes
with catalytic 1 demonstrated mixed in efficiency, featuring conversions of 20 – 100%. Mechanistic study indicates that an
iron silyl compound is unimportant in the bond–formation step and argues for a nucleophilic alkoxide intermediate. Most
important, mechanistic study reveals that the most immediate hurdle in the catalysis is the poor activation of 1,
demonstrating the necessity to fully activate the catalyst to realize the potential of iron in this reactivity.
University of Vermont, Department of Chemistry, Discovery Hall, Burlington, VT 05401, USA. E-mail: [email protected]
† Footnotes relating to the title and/or authors should appear here. Electronic Supplementary Information (ESI) available: [details of any supplementaryinformation available should be included here]. See DOI: 10.1039/x0xx00000x
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ARTICLE Dalton Transactions
Introduction
The dominance of noble metals in catalysis is, rightly, under
assault. The importance of metals such as palladium,
platinum, rhodium, and iridium is irrefutable, with some of
the more significant transformations including palladium–
catalyzed C–C or C–N cross-coupling,1 platinum–catalyzed
hydrosilylation of olefins,2 rhodium–catalyzed
hydrogenation and hydroformylation,3 and iridium–
catalyzed C–H activation.4 Despite their high utility to both
academia and industry, there has been a shift away from
these noble metals due to their cost, toxicity, and most
importantly, increasing scarcity.5 In their stead, a plethora
of transformations have emerged, including C–C cross-
coupling,6 hydrosilylation of olefins and aldehydes,7,8 and C–
H activation,9 by base metals including iron, manganese,
and cobalt. Iron is particularly attractive in catalysis due to
its high abundance and access to a range of oxidation
states.10,11 However, a variety of factors limit base metal–
catalyzed transformations, such as high catalyst loadings,
significant heating, or other forcing conditions to achieve
conversions comparable to those with noble metal
catalysts. Iron is no exception to these limitations, and it is
also noteworthy to mention that examples of mild,
photoactivated iron compounds are scarce in comparison
to thermally activated catalysts.12,13 This becomes an
unfortunate realization, as the development and
improvement of iron–based systems is paramount to
inexpensive and green chemical transformations.
Concomitant with the development of base metal
catalysis, chemists have been challenged with the
development of greener synthetic pathways.
Heterodehydrocoupling has gained momentum in green
chemistry, due to the atom-economical formation of
element–element bonds. The evolution of hydrogen as the
sole by-product is also attractive, providing an excellent
driving force and simplifying purification of products. Most
dehydrocoupling reactions can only be accomplished
catalytically with either a main group or transition–metal
compound.14 Consequentially, heterodehydrocoupling
catalysts are attractive for green, catalytic transformations.
The commercially available iron dimer [CpFe(CO)2]2 (1)
is a rare example that fulfils both previous points.
Heterodehydrocoupling via compound 1 has been already
been demonstrated on amine-borane substrates by
Manners and co-workers as well as between
dimethylformamide and PhMe2SiH by Waterman and co-
workers.15,16 Furthermore, compound 1 is known to
photoactivate under either ultraviolet or visible light
irradiation to produce two equivalents of a 17e- compound,
3, via the all terminal carbonyl intermediate 2 (Scheme 1).17
Thus, the photoirradiation of compound 1 may provide a
green and facile method to forming other element–
element bonds in the main group.
Scheme 1. Photoactivation pathway of compound 1 under either ultravioletor visible-light irradiation.17
Silyl ethers, or small molecules containing Si–O bonds, are
of importance in the protection of alcohols.18 Poly(silyl
ethers) are appealing due their hydrolytic instability in
acidic and basic medium.19 Molecules containing Si–N
bonds such as silamines are well established as bases and
silylating agents in organic syntheses,20 while poly(silazanes)
are sought after for their potential as ceramic precursors.21
Herein, we report 1 as a heterodehydrocoupling catalyst in
the formation of Si–O and Si–N bonds. Mechanistic study of
the reaction indicates nucleophilic attack of a silane by an
intermediate iron-alkoxide or -amide, but more germane to
the further development of iron, complete activation of 1
was not achieved in these reactions, which suggests that
full activation of iron catalyst precursors is an important
pursuit in developing base metal catalysis.
Results and Discussion
Condition OptimizationThis study sought to expand the scope of
heterodehydrocoupling by 1,15,16 initially investigating
coupling of primary silanes and alcohols. An equimolar
amount of nPrOH and PhSiH3 in the presence of 1 mol % of
1 in benzene-d6 solution was irradiated under visible-light
from a commercial LED bulb. After 24 h, the mixture
showed 32% conversion to PhSiH2(OnPr) and 43%
conversion to PhSiH(OnPr)2 as measured by 1H NMR
spectroscopy. The molar equivalences of alcohol and silane
were varied in an effort to generate the third addition silyl
ether product PhSi(OnPr)3. Four-fold excess of silane to one
equivalent of alcohol showed little effect on silyl ether
generation. However, increasing the concentration of
alcohol four-fold and the catalyst loading to 2 mol % of 1
generated PhSi(OnPr)3 in quantitative conversion after 24 h
according to 1H NMR spectroscopy (Table 1, Entry 1).22
These reaction conditions were uniformly applied to other
substrates (Eq. 1).
Catalytic Si-O Heterodehydrocoupling
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Dalton Transactions ARTICLE
(
1)
Coupling of alcohols such as BnOH (Bn = CH2Ph) andiPrOH with PhSiH3 was also accomplished with 1. Reaction
of BnOH and PhSiH3 in a 4:1 ratio generated PhSi(OBn)3
after 6 h, as determined by 1H and 29Si{1H} NMR
spectroscopy (Table 1, Entry 2).23,24 Reactions betweeniPrOH and PhSiH3 at similar alcohol/silane ratio proceeded
to incomplete conversion from PhSiH3 after 24 h, which
prompted an increase in the alcohol/silane ratio. Reaction
of a 5:1 mixture of iPrOH and PhSiH3 completely converted
from PhSiH3 by 24 h to PhSi(OiPr)3 (Table 1, Entry 3).24,25,26
Attempts at coupling PhSiH3 with heavily encumbered
alcohols such as tBuOH with 1 did not produce silyl ethers
according to 1H NMR spectroscopy.
Heterodehydrocoupling with secondary silanes using
compound 1 was also investigated. Reaction of PhMeSiH2
and nPrOH in a 1:4 ratio generated a single peak at δ -18.07
in 29Si{1H} NMR spectroscopy after 24 h under irradiation,
consistent with PhMeSi(OnPr)2 (Table 1, Entry 4). The final
resonance generated at δ 3.89 in 1H NMR spectroscopy
indicated 100% conversion to PhMeSi(OnPr)2. A similar
strategy was applied to reactions of iPrOH and PhSiH3 in a
5:1 ratio, where PhMeSi(OiPr)2 was afforded in 91%
conversion with 9% of PhMeSiH(OiPr) remaining after 24 h
(Table 1, Entry 6). Reaction of excess BnOH with PhMeSiH2
produced PhMeSi(OBn)2 in 100% conversion after 24 h
(Table 1, Entry 5).27
Reaction of nPrOH and Ph2SiH2 under visible-light irradiation
in the presence of 1 proceeded slowly according to 1H NMR
spectroscopy, but all starting material was consumed to a
single new product. Isolation of pure product from the
highly soluble Fp-catalyst remains a challenge, but in
comparison to similar resonances of known compounds, it
is hypothesized that Ph2Si(OnPr)2 was generated in 100%
conversion (Table 1, Entry 7). Reactions BnOH and Ph2SiH2
in a 4:1 ratio produced Ph2Si(OBn)2 in 100% conversion as
measured by 1H NMR spectroscopy (Table 1, Entry 8).24,28
Interestingly, reacting 5 equiv of iPrOH with Ph2SiH2
exclusively yielded Ph2SiH(OiPr)24 in quantitative conversion
with no evidence of fully substituted product Ph2Si(OiPr)2
(Table 1, Entry 9).24
Reaction of nPrOH and PhMe2SiH in a 5:1 ratio afforded
a new product, tentatively assigned to PhMe2Si(OnPr) based
on analogy to PhMe2Si(OBn) and PhMe2Si(OiPr), in 93%
conversion as a resonance at δ 6.67 in the 29Si{1H} NMR
spectrum (Table 1, Entry 10). Reaction of excess BnOH and
PhMe2SiH, however, showed complete disappearance of
PhMe2SiH in the 1H NMR spectrum and generation of
PhMe2Si(OBn) after 24 h (Table 1, Entry 11).27,29 Reaction ofiPrOH and PhMe2SiH in a 6:1 ratio showed 93% conversion
to PhMe2Si(OiPr) after 24 h according to 1H NMR
spectroscopy (Table 1, Entry 12).30
Table 1. Catalytic conditions for the coupling of alcohols and silanes.a
aConditi ons: 2.0
mol % of 1 under
visible– light
irradiation in benzene-d6 solution at ambient temperature for 24 h. Catalyst loading was with respect to silane. Reactions were monitored by 1H and29Si{1H} NMR spectroscopy. bRefers to mol. of alcohol per mol. of silane. cConversions were determined by 1H NMR integration. dLiterature spectral
data of these silyl ethers have not been previously reported.
Catalytic Si-N Heterodehydrocoupling
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entry silane alcohol equivb product conversion (%)c
1 PhSiH3nPrOH 4.0 PhSi(OnPr)3 100
2 PhSiH3 BnOH 4.0 PhSi(OBn)3 100
3 PhSiH3iPrOH 5.0 PhSi(OiPr)3 100
4 PhMeSiH2nPrOH 4.0 PhMeSi(OnPr)2
d 100
5 PhMeSiH2 BnOH 4.0 PhMeSi(OBn)2 100
6 PhMeSiH2iPrOH 5.0
PhMeSiH(OiPr),d PhMeSi(OiPr)2
d
9 91
7 Ph2SiH2nPrOH 4.0 Ph2Si(OnPr)2
d 100
8 Ph2SiH2 BnOH 4.0 Ph2Si(OBn)2 100
9 Ph2SiH2iPrOH 5.0 Ph2SiH(OiPr) 100
10 PhMe2SiH nPrOH 5.0 PhMe2Si(OnPr)d 93
11 PhMe2SiH BnOH 5.0 PhMe2Si(OBn) 100
12 PhMe2SiH iPrOH 6.0 PhMe2Si(OiPr) 93
ARTICLE Dalton Transactions
(2)
Compound 1 also proved to be competent at Si–N
heterodehydrocoupling but at higher catalyst loadings (Eq.
2). Silamines were produced less efficiently than silyl
ethers, as evident by the overall longer reaction times and
mixture of silamine products.
Treatment of nPrNH2 with PhSiH3 in a 6:1 amine/silane
ratio produced PhSiH2(HNnPr) in only 13% conversion after
4 h by 1H NMR spectroscopy. After 18 h, the reaction
produced PhSiH(HNnPr) in 50% conversion and
PhSiH2(HNnPr) in 23% conversion (Table 2, Entry 1).31
However, the analogous reaction with tBuNH2 and PhSiH3
produced PhSiH2(HNtBu) in 100% after only 4 h according to
1H NMR spectroscopy, and in 24 h, PhSiH2(HNtBu) and
PhSiH(HNtBu) were produced in 89% and 11% conversions
(Table 2, Entry 2).32,33 The disparity between the two amines
indicates that more basic (i.e., nucleophilic) amines give
greater silamine conversions. This observation was
supported by reaction of 4 equiv of iPrNH2 and PhSiH3 to
furnish PhSiH2(HNiPr) in 100% conversion after 20 h
according to 1H NMR spectroscopy (Table 2, Entry 4).34
Moreover, reaction of 4.7 equiv of Et2NH with PhSiH3
produced PhSiH2(NEt2) and PhSiH(NEt2)2 in 29% and 71%
conversions, respectively, after 24 h (Table 2, Entry 5).35
Finally, reaction of 4.6 equiv of PhNH2 with 9.3 mol % of 1,
PhSiH2(HNPh) was afforded in only 20% conversion after 20
h (Table 2, Entry 3).
Table 2. Catalytic conditions for the coupling of amines and silanes.a
entry silane amine loadingb equivc product conversion (%)d time (h)
1 PhSiH3nPrNH2 6.0 3.5
PhSiH2(HNnPr)PhSiH(HNnPr)2
2350 18
2 PhSiH3tBuNH2 7.8 6.0
PhSiH2(HNtBu)PhSiH(HNtBu)2
8911 24
3 PhSiH3 PhNH2 9.3 5.0 PhSiH2(HNPh) 20 20
4 PhSiH3iPrNH2 8.5 4.0 PhSiH2(HNiPr) 100 20
5 PhSiH3 Et2NH 8.5 6.0PhSiH2(NEt2)PhSiH(NEt2)2
2971 24
6 PhMeSiH2nPrNH2 9.3 5.0 PhMeSiH(HNnPr) 60 24
7 PhMeSiH2tBuNH2 7.8 5.0 PhMeSiH(HNtBu) 100 24
8 PhMeSiH2iPrNH2 9.3 4.0 PhMeSiH(HNiPr) 100 24
9 PhMeSiH2 Et2NH 10.2 6.0 PhMeSiH(NEt2) 100 24
10 Ph2SiH2nPrNH2 6.8 3.0 Ph2Si(HNnPr) 74 24
11 Ph2SiH2tBuNH2 8.1 6.0 Ph2Si(HNtBu) 40 24
12 Ph2SiH2iPrNH2 7.8 6.0 Ph2Si(HNiPr) 100 24
13 Ph2SiH2 Et2NH 8.5 7.0 Ph2SiH(NEt2) 22 24
aConditions: visible–light irradiation in benzene-d6 solution at ambient temperature. Reactions were monitored by 1H, 29Si{1H}, and 1H-29Si HSQC NMR
Spectroscopy. bMol % of 1 was with respect to silane. cEquiv of amine per 1 equiv of silane. dConversions were determined by 1H NMR integration.
Compound 1 was also demonstrated to be a competent
heterodehydrocoupling with amines and PhMeSiH2.
Treatment of nPrNH2 with PhMeSiH2 in a 5:1 amine/silane
ratio affords the corresponding silamine PhMeSiH(HNnPr) in
60% conversion after 24 h by 1H NMR spectroscopy (Table
2, Entry 6).34 Meanwhile, PhMeSiH(HNtBu) was generated in
100% conversion by 1H NMR spectroscopy after 24 h (Table
2, Entry 7).34 Furthermore, reacting 4 equiv of iPrNH2 with
PhMeSiH2 quantitatively produced PhMeSiH(HNiPr) after 24
h according to 1H and 1H-29Si HSQC NMR spectroscopy
(Table 2, Entry 8).34 The reaction between Et2NH and
PhMeSiH2 in a 6:1 ratio quantitatively converted from
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Dalton Transactions ARTICLE
PhMeSiH2 after 24 h according to 1H and 1H-29Si HSQC NMR
spectroscopy (Table 2, Entry 9).35 Notably, in addition to
PhMeSiH(NEt2), a second peak was also discernible 1H-29Si
HSQC NMR spectroscopy. Although it was initially believed
to be the second addition product PhMeSi(NEt2)2, literature
chemical shifts do not agree,35 and this minor byproduct
remains unidentified.
Finally, heterodehydrocoupling reactions with amines
and Ph2SiH2 catalyzed by compound 1 were also tested.
Reaction between nPrNH2 and Ph2SiH2 showed 74%
conversion to Ph2SiH(HNnPr) after 24 h according to 1H NMR
spectroscopy (Table 2, Entry 10).34 Conversely, reaction
between Ph2SiH2 and tBuNH2 showed only 50% conversion
to Ph2SiH(HNtBu) after 24 h (Table 2, Entry 11).32 The
observations indicated that steric factors can play a more
significant role when both the amine and silane exhibit
steric pressure. Of note, steric factors were more
pronounced with just the alcohol substrate in silyl ether
reactions (vide supra). This supposition is buttressed by the
reaction of Et2NH and Ph2SiH2 in which 22% conversion to
Ph2SiH(NEt2) was observed after 24 h, despite seven
equivalent of amine to silane (Table 2, Entry 13).33 The
balance can be tipped back with amine substitution where
reaction of iPrNH2 and Ph2SiH2 gave nearly quantitative
conversion to Ph2SiH(HNiPr) with a minor byproduct
discernible only in 1H-29Si HSQC NMR (Table 2, Entry 12).35
Mechanistic Study
Treatment of 1 with 1 equiv of nPrOH resulted in no change
as observed by 1H NMR spectroscopy after 24 h of visible-
light irradiation in a benzene-d6 solution. In contrast,
reaction of equimolar 1 and PhSiH3 over 24 h in benzene-d6
under visible–light irradiation resulted in 22% formation of
hydride 4 as measured by 1H NMR spectroscopy (Eq. 3).36 A
new iron compound, tentatively assigned as
Cp(CO)2FeSiH2Ph (5) based on resonances at δ 5.22 (SiH)
and δ 3.98 (C5H5), was observed in 27% conversion. Such
reactivity, the activation of an E–H bond under photolysis of
1 has been observed with phosphines.16
(3)
That P–H bond activation was also not quantitative,
doubtlessly related to the kinetics of visible–light activation
of 1.17 The known decomposition of 4 to 1 and the
possibility of a process that directly converts 4 to 5 with
free PhSiH3 likely contribute to the ~20% excess of 5 as
compared to 4. Observation of catalytic reactions with
PhSiH3 by 1H NMR spectroscopy confirm formation of 5
under catalytic conditions as well as apparently unreacted
1. Apparent Si–H bond activation products at iron are
consistently presented in catalytic reactions, regardless of
substrate.
This observation suggests that iron could activate the
organosilane substrate for nucleophilic attack by alcohol. To
test this supposition, a known silyl derivative,
Cp(CO)2FeSiMe2Ph (6) was prepared.37 Treatment of 6 with
1 equiv of nPrOH failed to afford the anticipated silyl ether
to any detectable extent by 1H NMR spectroscopy, and
variations on the reaction including 10 equiv of alcohol,
irradiation, or heating failed to afford silyl ether as well.
These observations demonstrate that the silyl derivative is
an off-cycle spectator, affirming the long-standing
observation that visible “intermediates” are not necessarily
catalytically relevant and that unseen compounds are often
the critical and active intermediates.38
Despite these negative results, the persistence of 1 and
silyl derivatives like 5 at the end of catalysis indicate that
the iron compound is largely preserved. Therefore, active
compounds are formally 18-electron derivatives,
Cp(CO)2FeX (X = silyl, hydride, alkoxide, etc.). Such
compounds are unavailable for organometallic (i.e.,
oxidative addition or σ-bond metathesis) steps due to
formal electron counts and the inaccessibility of these X
ligands for migratory insertion with carbonyl ligands.39,40
Such deduction leaves nucleophilic attack as the most
viable mechanistic hypothesis. Many metals promote
nucleophilicity of ligands.41 While we cannot observe an
iron alkoxide compound in solution, we cannot discount it.
Such an intermediate would be more nucleophilic than its
parent alcohol. Indeed, the relative reactivity of aniline and
iPrNH2 support nucleophilicity at the coupling partner.
While literature on isolated piano-stool iron alkoxides or
amidos is scarce, Nakazawa and coworkers have implicated
piano-stool iron-alkoxide and iron-thio intermediates in
catalytic silicon-oxygen and silicon-sulfur
heterodehydrocoupling, respectively.42,43
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ARTICLE Dalton Transactions
Scheme 2. Proposed mechanism for Si–O and Si–N heterodehydrocouplingcatalysed by 1.
Based on the stoichiometric reactions and observations
of the catalysis, an initial proposal for the catalytic cycle can
be made (Scheme 2). From both stoichiometric and
catalytic reactions, it is clear that the activation of 1 is not
complete, but irradiation would form two equiv of 3, which
would active silane substrate to hydride 4 and a silyl
compound. The silyl compound is an inactive spectator that
may be converted to 4 as hydrogen is evolved. Hydride 4
can decompose back to 1, which may also contribute to the
steady state concentration of 1 during catalysis as observed
by 1H NMR spectroscopy. However, 4 likely reacts with
alcohol to give a highly unstable alkoxide intermediate with
evolution of hydrogen. This alkoxide intermediate can then
attack a silane substrate to form product and regenerate 4.
Perhaps the most important observation from this
mechanistic proposal is not the Si–O or Si–N, bond-forming
step. There is far less active catalyst in the system than the
loading of 1 would indicate, even if the silyl intermediate
were completely inactive under catalytic conditions. This
information is a clear indication that a meager fraction of
potential activity is being realized.
Conclusions
A commercially available iron compound 1 is efficient at Si–
O heterodehydrocoupling under visible-light irradiation.
Reactions between alcohols and silanes catalyzed by 1
afforded silyl ether often in quantitative conversions from
starting silanes. Sterically encumbered silanes generally
required longer reaction times but provided near
quantitative conversion from starting silanes. Compound 1
is also a competent Si–N heterodehydrocoupling catalyst.
However, longer reaction times and higher catalyst loadings
were necessary to produce silamines in good conversions.
Furthermore, electron–rich amines were shown to be the
most effective substrates to convert to silamines.
Mechanistic study is consistent with nucleophilic attack of
an intermediate iron–alkoxide or –amide at the
organosilanes substrate. More important to future study,
though, is the necessity for complete activation of catalyst
to achieve optimal conversions. The ‘unactivated’ fraction
of catalyst may be a significant factor in the disparity
between base and noble metals in catalysis, suggesting an
area for deeper investigation. More specifically, this work
expands upon the heterodehydrocoupling capabilities of
1,15,16 and represents one of the few instances of mild, light-
activated iron-based catalysts.
Experimental
General Information
All reactions were prepared under purified a N2
atmosphere in an M. Braun glovebox. Cyclopentadienyl
dicarbonyl iron (II) dimer 1 was purified by sublimation.
Alcohols and amines were distilled from CaH2. Silanes were
used without further purification. Benzene-d6 was vacuum
transferred from NaK alloy. NMR spectra were acquired on
either a Varian 500 MHz spectrometer or a Bruker AXR 500
MHz spectrometer. Spectra recorded on both instruments
were reported to TMS (δ 0.00).
Catalytic Experiment Conditions
An oven-dried scintillation vial containing 1 (3.5 mg, 2.0
mol %) was charged with silane, followed by excess alcohol,
0.5 mL benzene-d6, and TMS. A similar method was
performed with amine coupling, however, loading of 1 was
determined by substrates. Mixtures were transferred to a J-
Young type polytetrafluoroethylene-valved NMR tube and
subsequently placed under visible-light irradiation.
Reactions were subjected to a cycle of freeze-pump-thaw
after 1 and 2 h of irradiation. All reactions were performed
at ambient temperature under irradiation in the visible
spectrum using a 40 W LED bulb.
Conflicts of interest
The authors have no conflicts of interest to declare.
Acknowledgements
This work was funded by the National Science Foundation
through CHE-1565658. The authors would like to thank Dr.
Monika Ivancic for assistance with NMR spectra.
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S1
Supporting Information for
Photoactivated Silicon-Oxygen and Silicon-Nitrogen Heterodehydrocoupling with a
Commercially Available Iron Compound
Matthew B. Reuter, Michael P. Cibuzar, James Hammerton, and Rory Waterman*
Department of Chemistry, University of Vermont, Burlington, VT 05045-0125
Contents General Information ................................................................................................................................. S2
Catalytic Experiment Conditions ............................................................................................................ S2
Spectroscopic Intermediates .................................................................................................................... S6
Catalytic Silicon-Oxygen Heterodehydrocoupling............................................................................... S12
PhSiH3 and nPrOH .............................................................................................................................. S12
PhSiH3 and BnOH. .............................................................................................................................. S15
PhSiH3 and iPrOH. .............................................................................................................................. S18
PhMeSiH2 and nPrOH ........................................................................................................................ S21
PhMeSiH2 and BnOH. ........................................................................................................................ S24
PhMeSiH2 and iPrOH ......................................................................................................................... S27
Ph2SiH2 and nPrOH. ............................................................................................................................ S31
Ph2SiH2 and BnOH ............................................................................................................................. S34
Ph2SiH2 and iPrOH ............................................................................................................................. S37
PhMe2SiH and nPrOH ........................................................................................................................ S40
PhMe2SiH and BnOH ......................................................................................................................... S43
PhMe2SiH and iPrOH ......................................................................................................................... S46
Catalytic Silicon-Nitrogen Heterodehydrocoupling............................................................................. S49
PhSiH3 and nPrNH2 ............................................................................................................................. S49
PhSiH3 and tBuNH2. ............................................................................................................................ S52
PhSiH3 and PhNH2 .............................................................................................................................. S55
PhSiH3 and iPrNH2.............................................................................................................................. S58
PhSiH3 and Et2NH .............................................................................................................................. S61
PhMeSiH2 and nPrNH2 ....................................................................................................................... S64
PhMeSiH2 and tBuNH2 ....................................................................................................................... S67
PhMeSiH2 and iPrNH2 ........................................................................................................................ S70
PhMeSiH2 and Et2NH ......................................................................................................................... S73
Ph2SiH2 and nPrNH2............................................................................................................................ S76
Ph2SiH2 and tBuNH2 ............................................................................................................................ S79
Ph2SiH2 and iPrNH2 ............................................................................................................................ S82
Ph2SiH2 and Et2NH ............................................................................................................................. S85
S2
General Information
All reactions were prepared under purified a N2 atmosphere in an M. Braun glovebox.
Cyclopentadienyl dicarbonyl iron (II) dimer 1 was purified by sublimation. Alcohols and amines
were distilled from CaH2. Silanes were used without further purification. Benzene-d6 was vacuum
transferred from NaK alloy. NMR spectra were acquired on either a Varian 500 MHz spectrometer
or a Bruker AXR 500 MHz spectrometer. Spectra recorded on both instruments were reported to
TMS (δ 0.00) for 1H and 29Si NMR.
Catalytic Experiment Conditions
An oven-dried scintillation vial containing 1 (3.5 mg, 2.0 mol %) was charged with silane,
followed by excess alcohol, 0.5 mL benzene-d6, and TMS. A similar method was performed with
amine coupling, however, loading of 1 was determined by substrates. Mixtures were transferred
to a J-Young type polytetrafluoroethylene-valved NMR tube and subsequently placed under
visible-light irradiation. Reactions were subjected to a cycle of freeze-pump-thaw after 1 and 2 h
of irradiation. All reactions were performed at ambient temperature under irradiation in the visible
spectrum using a 40 W LED bulb.
S3
Figure S.1 LED Reactor for Photocatalysis
S4
Table S1. Experimental and Literature NMR Characterization Data for Silyl Ethers.
Entry Compound 1H NMR (Lit) 29Si NMR (Lit) References
1 PhSi(OnPr)3 3.79a (3.84)b -57.99a 1
2 PhSi(OBn)3 4.84a (4.855)a -56.24a (-56.4)a 2, 3
3 PhSiH(OiPr)2 5.28a (5.19)a -34.52a (-34.8)a 4
4 PhSi(OiPr)3 4.32a (4.30-4.22)b -61.79a (-61.8)a 5, 3
5 PhMeSi(OnPr)2 3.67a -18.11a 6 PhMeSi(OBn)2 4.71a (4.91-4.82)b -15.48a 6
7 PhMeSiH(OiPr) 5.21a -6.65a 8 PhMeSi(OiPr)2 4.02a -21.83a 9 Ph2SiH(OnPr) 5.63a N/A 10 Ph2Si(OnPr)2 3.72a -32.20a 11 Ph2Si(OBn)2 4.79a (4.75)a -29.89a (-30.82)a 7, 3
12 Ph2SiH(OiPr) 5.64a (5.70)a -14.74a (-14.81a) 3
13 PhMe2Si(OnPr) 3.47a 6.66a 14 PhMe2Si(OBn) 4.56a (4.77)b 9.03a (8.9)b 6, 8
15 PhMe2Si(OiPr) 4.01a (4.111-4.030)b 4.21a 9
a in C6D6.
b in CDCl3. N.R. = Not Reported.
S5
Table S2. Experimental and Literature NMR Characterization Data for Silamines.
Entry Compound 1H NMR (Lit) 29Si NMR (Lit) Reference
16 PhSiH2(HNnPr) 5.08a -29.83a 17 PhSiH(HNnPr)2 5.17a (4.87)a -26.57a (-24.13) 10
18 PhSiH2(HNtBu) 5.09a (5.12)a -37.95a (-37.36)a 11
19 PhSiH(HNtBu)2 5.45a (5.23-5.22)a N/A (-30.61)a 12
20 PhSiH2(HNPh) 4.99a -36.77a 21 PhSiH2(HNiPr) 5.20a (5.19)a -30.8a (-38.22)a 13
22 PhSiH2(NEt2) 5.13a (5.10)a -25.20a (-25.44)a 14
23 PhSiH(NEt2)2 5.11a (5.13)a -18.95a (-19.18)a 14
24 PhMeSiH(HNnPr) 5.12a (5.15)a -14.61a (-14.23)a 13
25 PhMeSiH(HNtBu) 5.20a (5.23)a -21.35a (-21.33)a 13
26 PhMeSiH(HNiPr) 5.14a (5.16)a -16.95a (-16.82)a 13
27 PhMeSiH(NEt2) 5.09a (5.08)a -11.07a (-10.98)a 14
28 Ph2SiH(HNnPr) 5.57a (5.61)a -17.78a (-17.29)a 13
29 Ph2SiH(HNtBu) 5.68a (5.70)a -25.06a (-24.86)a 14
30 Ph2SiH(HNiPr) 5.60a (5.63)a -20.14a (-20.26)a 12
31 Ph2SiH(NEt2) 5.55a (5.55)a -14.35a (-14.27)a 14
a in C6D6. N.R. = Not Reported.
S6
Spectroscopic Intermediates
PhSiH3 and 1. An oven-dried scintillation vial containing 1 (35.3 mg, 0.1 mmol) was charged
with an equivalent of PhSiH3 (12.5 μL, 11.0 mg, 0.1 mmol), followed by 1.0 mL benzene-d6. The
mixture was transferred to a J-Young type polytetrafluoroethylene-valved NMR tube and
subsequently placed under visible-light irradiation. After a 1H NMR spectrum was taken after 24
h, an equimolar amount of nPrOH (7.5 μL, 6.0 mg, 0.1 mmol) was added, and the mixture was
irradiated for an additional 24 h.
Figure S.2 1H NMR spectrum of the stoichiometric reaction between PhSiH3 and 1 (benzene-d6,
500 MHz)
S7
Figure S.3 1H NMR spectrum of the stoichiometric reaction between PhSiH3 and 1 after added nPrOH (benzene-d6, 500 MHz)
S8
nPrOH and 1 under H2. An oven-dried scintillation vial containing 1 (35.3 mg, 0.1 mmol) was
charged with an equivalent of nPrOH (7.5 μL, 6.0 mg, 0.1 mmol), followed by 0.5 mL benzene-d6.
The mixture was transferred to a J-Young type polytetrafluoroethylene-valved NMR tube and
subsequently subjected to a cycle of freeze-pump-thaw. After an initial 1H NMR spectrum was
taken, the mixture was placed under hydrogen. After 1 h, an equimolar amount of PhSiH3 (12.5
μL, 11.0 mg, 0.1 mmol) was added and the mixture was left to react for 15 h.
Figure S.4 1H NMR spectrum of the stoichiometric reaction between nPrOH and 1 under H2
(benzene-d6, 500 MHz)
S9
Figure S.5 1H NMR spectrum of the stoichiometric reaction between nPrOH and 1 under H2 after
added PhSiH3 (benzene-d6, 500 MHz)
S10
nPrOH and 6. An oven-dried scintillation vial containing 6 (64.1 mg, 2.3 mmol) was charged with
an equivalent of nPrOH (17 μL, 13.6 mg, 2.3 mmol), followed by 0.5 mL benzene-d6. The mixture
was transferred to a J-Young type polytetrafluoroethylene-valved NMR tube.
Figure S.6 1H NMR spectrum of the stoichiometric reaction between nPrOH and 6 (benzene-d6,
99 MHz)
S11
Figure S.7 1H NMR spectrum of the stoichiometric reaction between nPrOH and 6 (benzene-d6,
99 MHz)
S12
Catalytic Silicon-Oxygen Heterodehydrocoupling
PhSiH3 and nPrOH.1 An oven-dried scintillation vial containing 1 (3.5 mg, 2.0 mol %) was
charged with PhSiH3 (61.5 μL, 54.0 mg, 0.5 mmol), followed by 0.5 mL benzene-d6, nPrOH (150.0
μL, 120.4 mg, 2.0 mmol), and TMS (17.0 μL, 11.0 mg, 25.0 mol %). The mixture was transferred
to a J-Young type polytetrafluoroethylene-valved NMR tube. After an initial 1H NMR spectrum
was collected, the reaction was irradiated under visible light. The reaction was subjected to a cycle
of freeze-pump-thaw after 1 and 2 h of irradiation. After 24 h, the reaction showed 100%
conversion to PhSi(OnPr)3 as measured by 1H NMR spectroscopy.
Figure S.8 Stacked 1H NMR spectra of the reaction between PhSiH3 and nPrOH catalyzed by 1
(benzene-d6, 500 MHz)
S13
Figure S.9 Stacked 1H NMR spectra of the reaction between PhSiH3 and nPrOH catalyzed by 1
(benzene-d6, 500 MHz)
S14
Figure S.10 29Si{1H} NMR spectrum of the reaction between PhSiH3 and nPrOH catalyzed by 1
(benzene-d6, 99 MHz)
*This artefact is resultant from the 29Si NMR probe and the borosilicate glass from the J-Young
NMR tube
S15
PhSiH3 and BnOH.2,3 An oven-dried scintillation vial containing 1 (3.5 mg, 2.0 mol %) was
charged with PhSiH3 (61.5 μL, 54.0 mg, 0.5 mmol), followed by 0.5 mL benzene-d6, BnOH (210.0
μL, 219.2 mg, 2.0 mmol), and TMS (17.0 μL, 11.0 mg, 25.0 mol %). After 6 h of irradiation, the
reaction showed 100% conversion to PhSi(OBn)3 as measured by 1H NMR spectroscopy.
Figure S.11 Stacked 1H NMR spectra of the reaction between PhSiH3 and BnOH catalyzed by 1
(benzene-d6, 500 MHz)
S16
Figure S.12 Stacked 1H NMR spectra of the reaction between PhSiH3 and BnOH catalyzed by 1
(benzene-d6, 500 MHz)
S17
Figure S.13 29Si{1H} NMR spectrum of the reaction between PhSiH3 and BnOH catalyzed by 1
(benzene-d6, 99 MHz)
S18
PhSiH3 and iPrOH.4,3,5 An oven-dried scintillation vial containing 1 (3.5 mg, 2.0 mol %) was
charged with PhSiH3 (61.5 μL, 54.0 mg, 0.5 mmol), followed by 0.5 mL benzene-d6, iPrOH (190.0
μL, 149.3 mg, 2.5 mmol), and TMS (17.0 μL, 11.0 mg, 25.0 mol %). After 24 h of irradiation, the
reaction showed 100% conversion to PhSi(OiPr)3 as measured by 1H NMR spectroscopy.
Figure S.14 Stacked 1H NMR spectra of the reaction between PhSiH3 and iPrOH catalyzed by 1
(benzene-d6, 500 MHz)
S19
Figure S.15 1H NMR spectrum of the reaction between PhSiH3 and iPrOH catalyzed by 1
(benzene-d6, 500 MHz)
S20
Figure S.16 29Si{1H} NMR spectrum of the reaction between PhSiH3 and iPrOH catalyzed by 1
(benzene-d6, 99 MHz)
S21
PhMeSiH2 and nPrOH. An oven-dried scintillation vial containing 1 (3.5 mg, 2.0 mol %) was
charged with PhMeSiH2 (68.5 μL, 60.9 mg, 0.5 mmol), followed by 0.5 mL benzene-d6, nPrOH
(150.0 μL, 120.4 mg, 2.0 mmol), and TMS (11.5 μL, 7.4 mg, 16.9 mol %). After 24 h of irradiation,
the reaction demonstrated 100% conversion from PhMeSiH2 as measured by 1H NMR
spectroscopy. Although product isolation was unsuccessful, it was hypothesized that the resonance
at δ 3.67 was PhMeSi(OnPr)2 and was produced in 100% conversion.
Figure S.17 Stacked 1H NMR spectra of the reaction between PhMeSiH2 and nPrOH catalyzed by
1 (benzene-d6, 500 MHz)
S22
Figure S.18 1H NMR spectrum of the reaction between PhMeSiH2 and nPrOH catalyzed by 1
(benzene-d6, 500 MHz)
S23
Figure S.19 29Si{1H} NMR spectrum of the reaction between PhMeSiH2 and nPrOH catalyzed by
1 (benzene-d6, 99 MHz)
S24
PhMeSiH2 and BnOH.6 An oven-dried scintillation vial containing 1 (3.5 mg, 2.0 mol %) was
charged with PhMeSiH2 (68.5 μL, 60.9 mg, 0.5 mmol), followed by 0.5 mL benzene-d6, BnOH
(210.0 μL, 219.2 mg, 2.0 mmol), and TMS (11.5 μL, 7.4 mg, 16.9 mol %). After 24 h of irradiation,
the reaction showed 100% conversion to PhMeSi(OBn)2 as measured by 1H NMR spectroscopy.
Figure S.20 Stacked 1H NMR spectra of the reaction between PhMeSiH2 and BnOH catalyzed by
1 (benzene-d6, 500 MHz)
S25
Figure S.21 1H NMR spectrum of the reaction between PhMeSiH2 and BnOH catalyzed by 1
(benzene-d6, 500 MHz)
S26
Figure S.22 29Si{1H} NMR spectrum of the reaction between PhMeSiH2 and BnOH catalyzed by
1 (benzene-d6, 99 MHz)
S27
PhMeSiH2 and iPrOH. An oven-dried scintillation vial containing 1 (3.5 g, 2.0 mol %) was
charged with PhMeSiH2 (68.5 μL, 60.9 mg, 0.5 mmol), followed by 0.5 mL benzene-d6, iPrOH
(190.0 μL, 149.3 mg, 2.5 mmol), and TMS (11.5 μL, 7.4 mg, 16.9 mol %). Although product
isolation was unsuccessful, it was hypothesized that the resonance at δ 5.20 corresponded to
PhMeSiH(OiPr) and was produced in 9% conversion, while the resonance at δ 4.27 corresponded
to the PhMeSi(OiPr)2 and was produced in 91% yield, as measured by 1H NMR spectroscopy.
Figure S.23 Stacked 1H NMR spectra of the reaction between PhMeSiH2 and iPrOH catalyzed by
1 (benzene-d6, 500 MHz)
S28
Figure S.24 1H NMR spectrum of the reaction between PhMeSiH2 and iPrOH catalyzed by 1
(benzene-d6, 500 MHz)
S29
Figure S.25 29Si{1H} NMR spectrum of the reaction between PhMeSiH2 and iPrOH catalyzed by
1 (benzene-d6, 99 MHz)
S30
Figure S.26 1H-29Si{1H} HSQC spectrum of the reaction between PhMeSiH2 and iPrOH catalyzed
by 1 (benzene-d6, 99 MHz)
S31
Ph2SiH2 and nPrOH. An oven-dried scintillation vial containing 1 (3.5 mg, 2.0 mol %) was
charged with Ph2SiH2 (93.0 μL, 92.3 mg, 0.5 mmol), followed by 0.5 mL benzene-d6, nPrOH
(150.0 μL, 120.4 mg, 2.0 mmol), and TMS (11.5 μL, 7.4 mg, 16.9 mol %). After 24 h of irradiation,
the reaction reached 100% conversion from Ph2SiH2 according to 1H NMR spectroscopy.
Although product isolation was unsuccessful, it was hypothesized that the resonance at δ 3.72
corresponds to Ph2Si(OnPr)2 and was produced in 100% conversion.
Figure S.27 Stacked 1H NMR spectra of the reaction between Ph2SiH2 and nPrOH catalyzed by 1
(benzene-d6, 500 MHz)
S32
Figure S.28 1H NMR spectrum of the reaction between Ph2SiH2 and nPrOH catalyzed by 1
(benzene-d6, 500 MHz)
S33
Figure S.29 29Si{1H} NMR spectrum of the reaction between Ph2SiH2 and nPrOH catalyzed by 1
(benzene-d6, 99 MHz)
S34
Ph2SiH2 and BnOH.7,3 An oven-dried scintillation vial containing 1 (3.5 mg, 2.0 mol %) was
charged with Ph2SiH2 (93.0 μL, 92.3 mg, 0.5 mmol), followed by 0.5 mL benzene-d6, BnOH
(210.0 μL, 219.2 mg, 2.0 mmol), and TMS (11.5 μL, 7.4 mg, 16.9 mol %). After 24 h of irradiation,
the reaction showed 100% conversion to Ph2Si(OBn)2 according to 1H NMR spectroscopy.
Figure S.30 Stacked 1H NMR spectra of the reaction between Ph2SiH2 and BnOH catalyzed by 1
(benzene-d6, 500 MHz)
S35
Figure S.31 1H NMR spectrum of the reaction between Ph2SiH2 and BnOH catalyzed by 1
(benzene-d6, 500 MHz)
S36
Figure S.32 29Si{1H} NMR spectrum of the reaction between Ph2SiH2 and BnOH catalyzed by 1
(benzene-d6, 99 MHz)
S37
Ph2SiH2 and iPrOH.3 An oven-dried scintillation vial containing 1 (3.5 mg, 2.0 mol %) was
charged with Ph2SiH2 (93.0 μL, 92.3 mg, 0.5 mmol), followed by 0.5 mL benzene-d6, iPrOH (190.0
μL, 149.3 mg, 2.5 mmol), and TMS (11.5 μL, 7.4 mg, 16.9 mol %). After 24 h of irradiation, the
reaction showed 100% conversion to Ph2SiH(OiPr) according to 1H NMR spectroscopy.
Figure S.33 Stacked 1H NMR spectra of the reaction between Ph2SiH2 and iPrOH catalyzed by 1
(benzene-d6, 500 MHz)
S38
Figure S.34 1H NMR spectrum of the reaction between Ph2SiH2 and iPrOH catalyzed by 1
(benzene-d6, 500 MHz)
S39
Figure S.35 29Si{1H} NMR spectrum of the reaction between Ph2SiH2 and iPrOH catalyzed by 1
(benzene-d6, 99 MHz)
S40
PhMe2SiH and nPrOH. An oven-dried scintillation vial containing 1 (3.5 mg, 2.0 mol %) was
charged with PhMe2SiH (76.5 μL, 68.0 mg, 0.5 mmol), followed by 0.5 mL benzene-d6, nPrOH
(150.0 μL, 150.2 mg, 2.5 mmol), and TMS (6.0 μL, 3.8 mg, 8.8 mol %). After 24 h of irradiation,
the reaction showed partial disappearance of PhMe2SiH at δ 4.60 according to 1H NMR
spectroscopy. It was hypothesized that the peak at δ 3.47 was PhMe2Si(OnPr) and was produced
in 93% conversion.
Figure S.36 Stacked 1H NMR spectra of the reaction between PhMe2SiH and nPrOH catalyzed by
1 (benzene-d6, 500 MHz)
S41
Figure S.37 1H NMR spectrum of the reaction between PhMe2SiH and nPrOH catalyzed by 1
(benzene-d6, 500 MHz)
S42
Figure S.38 29Si{1H} NMR spectrum of the reaction between PhMe2SiH and nPrOH catalyzed by
1 (benzene-d6, 99 MHz)
S43
PhMe2SiH and BnOH.6,8 An oven-dried scintillation vial containing 1 (3.6 mg, 2.0 mol %) was
charged with PhMe2SiH (76.5 μL, 68.0 mg, 0.5 mmol), followed by 0.5 mL benzene-d6, BnOH
(259.0 μL, 270.4 mg, 2.5 mmol), and TMS (6.0 μL, 3.8 mg, 8.8 mol %). After 2 h of irradiation,
the reaction showed 100% conversion to PhMe2Si(OBn) according to 1H NMR spectroscopy.
Figure S.39 Stacked 1H NMR spectra of the reaction between PhMe2SiH and BnOH catalyzed by
1 (benzene-d6, 500 MHz)
S44
Figure S.40 1H NMR spectrum of the reaction between PhMe2SiH and BnOH catalyzed by 1
(benzene-d6, 500 MHz)
S45
Figure S.41 29Si{1H} NMR spectrum of the reaction between PhMe2SiH and BnOH catalyzed by
1 (benzene-d6, 99 MHz)
S46
PhMe2SiH and iPrOH.9 An oven-dried scintillation vial containing 1 (3.6 mg, 2.0 mol %) was
charged with PhMe2SiH (76.5 μL, 68.0 mg, 0.5 mmol), followed by 0.5 mL benzene-d6, iPrOH
(229.0 μL, 180.0 mg, 3.0 mmol), and TMS (6.0 μL, 3.8 mg, 8.8 mol %). After 24 h of irradiation,
the reaction showed 93% conversion to PhMe2Si(OiPr) according to 1H NMR spectroscopy.
Figure S.42 Stacked 1H NMR spectra of the reaction between PhMe2SiH and iPrOH catalyzed by
1 (benzene-d6, 500 MHz)
S47
Figure S.43 1H NMR spectrum of the reaction between PhMe2SiH and iPrOH catalyzed by 1
(benzene-d6, 500 MHz)
S48
Figure S.44 29Si{1H} NMR spectrum of the reaction between PhMe2SiH and iPrOH catalyzed by
1 (benzene-d6, 99 MHz)
S49
Catalytic Silicon-Nitrogen Heterodehydrocoupling
PhSiH3 and nPrNH2.10 An oven-dried scintillation vial containing 1 (3.6 mg, 6.0 mol %) was
charged with PhSiH3 (18.7 mg, 0.2 mmol), followed by 0.5 mL benzene-d6, nPrNH2 (41.8 mg, 0.7
mmol), and TMS (8.4 mg, 56.0 mol %). After 18 h of irradiation, it was hypothesized that the
resonance at δ 5.08 was PhSiH2(HNnPr) and was produced in 23% conversion, and the resonance
at δ 5.17 was PhSiH(HNnPr)2 and was produced in 50% yield. A 1H NMR spectrum was taken at
24 h and showed significant broadening to the point where resonances at δ 5.08 and δ 5.17 were
indistinguishable.
Figure S.45 Stacked 1H NMR spectra of the reaction between PhSiH3 and nPrNH2 catalyzed by 1
(benzene-d6, 500 MHz)
S50
Figure S.46 1H NMR spectrum of the reaction between PhSiH3 and nPrNH2 catalyzed by 1
(benzene-d6, 500 MHz)
S51
Figure S.47 1H-29Si{1H} HSQC spectra of the reaction between PhSiH3 and nPrNH2 catalyzed
by 1 (benzene-d6, 99 MHz)
S52
PhSiH3 and tBuNH2.11,12 An oven-dried scintillation vial containing 1 (3.6 mg, 7.8 mol %) was
charged with PhSiH3 (14.3 mg, 0.1 mmol), followed by 0.5 mL benzene-d6, tBuNH2 (42.2 mg, 0.6
mmol), and TMS (7.3 mg, 64.0 mol %). After 24 h of irradiation, the mixture showed 89%
conversion to PhSiH2(HNtBu) and 11% conversion to PhSiH(HNtBu)2 according to 1H NMR
spectroscopy.
Figure S.48 Stacked 1H NMR spectra of the reaction between PhSiH3 and tBuNH2 catalyzed by 1
(benzene-d6, 500 MHz)
S53
Figure S.49 1H NMR spectrum of the reaction between PhSiH3 and tBuNH2 catalyzed by 1
(benzene-d6, 500 MHz)
S54
Figure S.50 29Si{1H} NMR spectrum of the reaction between PhSiH3 and tBuNH2 catalyzed by 1
(benzene-d6, 99 MHz)
S55
PhSiH3 and PhNH2. An oven-dried scintillation vial containing 1 (3.6 mg, 9.3 mol %) was
charged with PhSiH3 (11.9 mg, 0.1 mmol), followed by 0.5 mL benzene-d6, PhNH2 (47.0 mg, 0.5
mmol), and TMS (12.8 mg, 132.0 mol %). After 20 h of irradiation, it was hypothesized that the
resonance at δ 5.07 was PhSiH2(HNPh) which was produced in 20% conversion according to 1H
NMR spectroscopy.
Figure S.51 Stacked 1H NMR spectra of the reaction between PhSiH3 and PhNH2 catalyzed by 1
(benzene-d6, 500 MHz)
S56
Figure S.52 1H NMR spectrum of the reaction between PhSiH3 and PhNH2 catalyzed by 1
(benzene-d6, 500 MHz)
S57
Figure S.53 1H-29Si{1H} HSQC spectra of the reaction between PhSiH3 and PhNH2 catalyzed by
1 (benzene-d6, 99 MHz)
S58
PhSiH3 and iPrNH2.13 An oven-dried scintillation vial containing 1 (3.6 mg, 8.5 mol %) was
charged with PhSiH3 (13.5 mg, 0.1 mmol), followed by 0.5 mL benzene-d6, iPrNH2 (26.3 mg, 0.4
mmol), and TMS (4.2 mg, 40.0 mol %). After 20 h of irradiation, the mixture showed 100%
conversion to PhSiH2(HNiPr) according to 1H NMR spectroscopy.
Figure S.54 Stacked 1H NMR spectra of the reaction between PhSiH3 and iPrNH2 catalyzed by 1
(benzene-d6, 500 MHz)
S59
Figure S.55 1H NMR spectrum of the reaction between PhSiH3 and iPrNH2 catalyzed by 1
(benzene-d6, 500 MHz)
S60
Figure S.56 1H-29Si{1H} HSQC spectra of the reaction between PhSiH3 and iPrNH2 catalyzed by
1 (benzene-d6, 99 MHz)
S61
PhSiH3 and Et2NH.14 An oven-dried scintillation vial containing 1 (3.6 mg, 8.5 mol %) was
charged with PhSiH3 (12.8 mg, 0.1 mmol), followed by 0.5 mL benzene-d6, Et2NH (41.5 mg, 0.6
mmol), and TMS (5.0 mg, 47.2 mol %). After 4 h of irradiation, the mixture showed 29%
conversion to PhSiH2(NEt2) and 71% conversion to PhSiH(NEt2)2 according to 1H NMR
spectroscopy.
Figure S.57 Stacked 1H NMR spectra of the reaction between PhSiH3 and Et2NH catalyzed by 1
(benzene-d6, 500 MHz)
S62
Figure S.58 1H NMR spectrum of the reaction between PhSiH3 and Et2NH catalyzed by 1
(benzene-d6, 500 MHz)
S63
Figure S.59 1H-29Si{1H} HSQC spectra of the reaction between PhSiH3 and Et2NH catalyzed by
1 (benzene-d6, 99 MHz)
S64
PhMeSiH2 and nPrNH2.13 An oven-dried scintillation vial containing 1 (3.6 mg, 9.3 mol %) was
charged with PhMeSiH2 (13.2 mg, 0.1 mmol), followed by 0.5 mL benzene-d6, nPrNH2 (27.5 g,
0.5 mmol), and TMS (6.2 mg, 64.0 mol %). After 24 h of irradiation, the mixture showed 60%
conversion to PhMeSiH(HNnPr) according to 1H NMR spectroscopy.
Figure S.60 Stacked 1H NMR spectra of the reaction between PhMeSiH2 and nPrNH2 catalyzed
by 1 (benzene-d6, 500 MHz)
S65
Figure S.61 1H NMR spectrum of the reaction between PhMeSiH2 and nPrNH2 catalyzed by 1
(benzene-d6, 500 MHz)
S66
Figure S.62 1H-29Si{1H} HSQC spectra of the reaction between PhMeSiH2 and nPrNH2 catalyzed
by 1 (benzene-d6, 99 MHz)
S67
PhMeSiH2 and tBuNH2.13 An oven-dried scintillation vial containing 1 (3.6 mg, 7.8 mol %) was
charged with PhMeSiH2 (15.7 mg, 0.1 mmol), followed by 0.5 mL benzene-d6, tBuNH2 (39.1 mg,
0.5 mmol), and TMS (5.3 mg, 46.2 mol %). After 24 h of irradiation, the reaction showed 100%
conversion to PhMeSiH(HNtBu) according to 1H NMR spectroscopy.
Figure S.63 Stacked 1H NMR spectra of the reaction between PhMeSiH2 and tBuNH2 catalyzed
by 1 (benzene-d6, 500 MHz)
S68
Figure S.64 1H NMR spectrum of the reaction between PhMeSiH2 and tBuNH2 catalyzed by 1
(benzene-d6, 500 MHz)
S69
Figure S.65 1H-29Si{1H} HSQC spectra of the reaction between PhMeSiH2 and tBuNH2 catalyzed
by 1 (benzene-d6, 99 MHz)
S70
PhMeSiH2 and iPrNH2.13 An oven-dried scintillation vial containing 1 (3.6 mg, 9.3 mol %) was
charged with PhMeSiH2 (13.5 g, 0.1 mmol) followed by 0.5 mL benzene-d6, iPrNH2 (26.3 mg, 0.4
mmol), and TMS (6.3 mg, 64.9 mol %). After 24 h of irradiation, it was hypothesized that the
reaction reached 100% conversion from PhMeSiH2 according to 1H NMR spectroscopy.
Figure S.66 Stacked 1H NMR spectra of the reaction between PhMeSiH2 and iPrNH2 catalyzed by
1 (benzene-d6, 500 MHz)
S71
Figure S.67 1H NMR spectrum of the reaction between PhMeSiH2 and iPrNH2 catalyzed by 1
(benzene-d6, 500 MHz)
S72
Figure S.68 1H-29Si{1H} HSQC spectra of the reaction between PhMeSiH2 and iPrNH2 catalyzed
by 1 (benzene-d6, 99 MHz)
S73
PhMeSiH2 and Et2NH.14 An oven-dried scintillation vial containing 1 (3.6 mg, 10.2 mol %) was
charged with PhMeSiH2 (12.8 mg, 0.1 mmol), followed by 0.5 mL benzene-d6, Et2NH (41.5 mg,
0.6 mmol), and TMS (4.8 mg, 54.4 mol %). After 24 h of irradiation, the reaction showed 100%
conversion from PhMeSiH2 according to 1H NMR spectroscopy.
Figure S.69 Stacked 1H NMR spectra of the reaction between PhMeSiH2 and Et2NH catalyzed by
1 (benzene-d6, 500 MHz)
S74
Figure S.70 1H NMR spectrum of the reaction between PhMeSiH2 and Et2NH catalyzed by 1
(benzene-d6, 500 MHz)
S75
Figure S.71 1H-29Si{1H} HSQC spectra of the reaction between PhMeSiH2 and Et2NH catalyzed
by 1 (benzene-d6, 99 MHz)
S76
Ph2SiH2 and nPrNH2.13 An oven-dried scintillation vial containing 1 (3.6 mg, 6.8 mol %) was
charged with Ph2SiH2 (28.4 mg, 0.2 mmol), followed by 0.5 mL benzene-d6, nPrNH2 (37.0 mg, 0.6
mmol), and TMS (5.2 mg, 39.3 mol %). After 24 h of irradiation, the reaction showed 74%
conversion to Ph2SiH(HNnPr) according to 1H NMR spectroscopy.
Figure S.72 Stacked 1H NMR spectra of the reaction between Ph2SiH2 and nPrNH2 catalyzed by
1 (benzene-d6, 500 MHz)
S77
Figure S.73 1H NMR spectrum of the reaction between Ph2SiH2 and nPrNH2 catalyzed by 1
(benzene-d6, 500 MHz)
S78
Figure S.74 1H-29Si{1H} HSQC spectra of the reaction between Ph2SiH2 and nPrNH2 catalyzed by
1 (benzene-d6, 99 MHz)
S79
Ph2SiH2 and tBuNH2.14 An oven-dried scintillation vial containing 1 (4.0 mg, 8.1 mol %) was
charged with Ph2SiH2 (25.1 mg, 0.1 mmol), followed by 0.5 mL benzene-d6, tBuNH2 (45.8 mg,
0.6 mmol), and TMS (3.8 mg, 30.8 mol %). After 24 h of irradiation, the reaction showed 44%
conversion to Ph2SiH(HNtBu) according to 1H NMR spectroscopy.
Figure S.75 Stacked 1H NMR spectra of the reaction between Ph2SiH2 and tBuNH2 catalyzed by
1 (benzene-d6, 500 MHz)
S80
Figure S.76 1H NMR spectrum of the reaction between Ph2SiH2 and tBuNH2 catalyzed by 1
(benzene-d6, 500 MHz)
S81
Figure S.77 1H-29Si{1H} HSQC spectra of the reaction between Ph2SiH2 and tBuNH2 catalyzed
by 1 (benzene-d6, 99 MHz)
S82
Ph2SiH2 and iPrNH2.12 An oven-dried scintillation vial containing 1 (3.6 mg, 7.8 mol %) was
charged with Ph2SiH2 (23.3 mg, 0.1 mmol), followed by 0.5 mL benzene-d6, iPrNH2 (36.3 mg, 0.6
mmol), and TMS (5.5 mg, 48.0 mol %). After 24 h of irradiation, the reaction had reached 100%
conversion from Ph2SiH2 according to 1H NMR spectroscopy. However, in addition to
Ph2SiH(HNiPr) at δ -20.14 shown in 1H-29Si HSQC, a second signal appeared at δ -21.76. Although
this was hypothesized to be Ph2Si(HNiPr)2, the 29Si NMR chemical shift does not match literature
values.
Figure S.78 Stacked 1H NMR spectra of the reaction between Ph2SiH2 and iPrNH2 catalyzed by 1
(benzene-d6, 500 MHz)
S83
Figure S.79 1H NMR spectrum of the reaction between Ph2SiH2 and iPrNH2 catalyzed by 1
(benzene-d6, 500 MHz)
S84
Figure S.80 1H-29Si{1H} HSQC spectra of the reaction between Ph2SiH2 and iPrNH2 catalyzed
by 1 (benzene-d6, 99 MHz)
S85
Ph2SiH2 and Et2NH.14 An oven-dried scintillation vial containing 1 (3.6 mg, 8.5 mol %) was
charged with Ph2SiH2 (22.7 mg, 0.1 mmol) followed by 0.5 mL benzene-d6, Et2NH (47.5 mg, 0.7
mmol), and TMS (6.5 mg, 61.4 mol %). After 24 h of irradiation, the reaction showed 22%
conversion to Ph2SiH(NEt2) according to 1H NMR spectroscopy.
Figure S.81 Stacked 1H NMR spectra of the reaction between Ph2SiH2 and Et2NH catalyzed by 1
(benzene-d6, 500 MHz)
S86
Figure S.82 1H NMR spectrum of the reaction between Ph2SiH2 and Et2NH catalyzed by 1
(benzene-d6, 500 MHz)
S87
Figure S.83 1H-29Si{1H} HSQC spectra of the reaction between Ph2SiH2 and Et2NH catalyzed by
1 (benzene-d6, 99 MHz)
S88
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