Functionalized vinylsilanes via highly efficient and recyclable Pt-nanoparticle catalysed hydrosilylation of alkynes

Article abstract of DOI:10.1039/c7dt00544j

A mild, selective and facile synthesis of vinylsilanes via a recyclable platinum nanoparticle catalysed hydrosilylation of alkynes is reported. Various functionalized alkynes are selectively hydrosilylated to furnish functional β-E vinylsilanes in high yi

Full text of DOI:10.1039/c7dt00544j

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ISSN 1477-9226
PAPER
Joseph T. Hupp, Omar K. Farha et al.
Efficient extraction of sulfate from water using
framework
a Zr-metal–organic
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Functionalized Vinylsilanes Via Highly Efficient and Recyclable Pt-
Nanoparticle Catalysed Hydrosilylation of Alkynes
Bhanu P. S. Chauhan,*,a and Alok Sarkara,†
Received 00th January 20xx,
Accepted 00th January 20xx
DOI: 10.1039/x0xx00000x
www.rsc.org/
A mild, selective and facile synthesis of vinylsilanes via a recyclable heterogeneous counterparts such as platinum-metal supported
platinum nanoparticle catalysed hydrosilylation of alkynes is on titania,14 silica,19 and activated-carbon,20 have provided
reported. Various functionalized alkynes are selectively benefits in terms of ease of catalyst recovery and recyclability,
hydrosilylated to furnish functional -E vinylsilanes in high yields. but the reactivity and selectivity of such catalysts are generally
The catalytic effectiveness, ease of catalyst recovery and very low and often require stringent reaction condition to
recyclability of polysiloxane stabilized Pt-nanoparticle catalyst are achieve 100% conversion.
the major achievements of this work. Detailed in situ
characterization using Electron Microscopy and controlled
Scheme 1: Hydrosilylation of alkynes with functional silanes
poisoning experiments supports the participation of Pt-
nanoparticles as an active catalyst.
Vinylsilanes are versatile organosilicon family of compounds,
which have found applications as important building blocks for
the construction of novel organic/inorganic hybrid functional
materials.1-2 In last few decades, the utilization of this specific
class of organometalloids in transition-metal catalysed cross-
coupling reactions has grown tremendously due to their
relatively low toxicity, high chemical stability and low molecular
weight when compared with other organotin, organoboron, and
organozinc counterparts.3-9
Efforts in our laboratory, have been directed towards creating
heterogeneous platforms of selectively cross-linked
polysiloxanes, in which the metal nanoparticles are nucleated in
desired concentration and morphology. Using such catalysts, we
have examined and reported highly efficient, mild and
recyclable catalysts for hydrolytic oxidation of organosilane,
hydrosilylation of olefin and polyolefins where the air-stable
solid catalyst first forms a homogeneous/dispersed phase with
the reactant molecules and separates out on the way to the end
of reaction.22-24
To further extend our ongoing efforts towards the development
of such hybrid-phase catalyst to produce industrially relevant
building blocks, we wish to present herein a highly selective,
mild and practical hydrosilylation reaction of functional alkynes
with hydrosilanes to produce corresponding vinylsilanes in high
yields. In this communication, catalytic performance of
heterogeneous platinum nanoparticles powders in terms of
activity, selectivity and recyclability is also examined. In
Metal complex catalysed hydrosilylation of alkynes has been
investigated extensively because it can lead to variety of
vinylsilanes with 100% atom efficiency (scheme 1). 10-21
Platinum based catalysts have been most common and active
catalysts for regio- and stereospecific hydrosilylation reactions.
A large body of platinum catalysed hydrosilylation studies has
been conducted under homogeneous conditions where
expensive Pt-catalysts are not recyclable. Moreover, due to their
extremely high reactivity, the handling of the catalysts often
requires inert atmosphere compromising their utility for large
scale production in industrial setting. On the other hand, their
aEngineered Nanomaterials Laboratory, Department of Chemistry, William
Paterson University, 300 Pompton Road, Wayne, New Jersey 07470-2103, USA.
Email: chauhanbps@wpunj.edu, Phone: +1 973 720 2470; Fax: +1 973 720 2972
†Present Address: Momentive Performance Materials Pvt. Ltd., Survey No. 9,
Electronic City (West), Hosur Road, Bangalore 560100, India. Email:
alok.sarkar@momentive.com, Phone: +91 80 4935 2121, Fax: +91 80 4935 2233
Electronic Supplementary Information (ESI) available: See DOI: 10.1039/x0xx00000x
This journal is © The Royal Society of Chemistry 20xx
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addition, the initial studies of the nature and surface reactions amount of polysiloxane-platinum nanoparticles, the
View Article Online
DOI: 10.1039/C7DT00544J
triethylsilane smoothly underwent hydrosilylation reaction with
of polysiloxane stabilized Pt- nanoparticles is also reported.
The polysiloxane stabilized platinum nanoparticles were 1-trimethylsilyl propyne at room temperature affording a
prepared according to the slightly modified procedure reported mixture of only two isomers in a ratio of 91: 9. We were
earlier by our group.25 Briefly, the platinum complex, Me2Pt surprised to encounter such a selective transformation because
(COD) (COD: 1,5 cyclo-octadiene) (0.25 mmol, 0.084 g), and unsymmetrially disubstituted alkyne can give rise to four
polymethylhydrosiloxane (PMHS, average MW ~2000) (10.00 possible isomers (-E, -E, -Z, -Z and-Z) depending upon the
mmol, 0.60 mL) were mixed in 50 mL toluene in a 200-mL round mode of addition of Si-H bond across the triple bond.
o
bottom flask. The reaction mixture was stirred at 80 C for 24 h
under positive pressure of nitrogen. The reduction reaction of
Scheme 3: Hydrosilylation of Trimehylsilyl-1-propyne (1) with functional silanes (2a-f).
Me2Pt (COD) to Pt-particles was monitored with UV-Vis
spectroscopy, which revealed a gradual disappearance of
intense absorption peak at ~320nm associated with the Me2Pt
(COD) leading to a featureless UV-Vis spectrum.
Scheme 2: Synthesis of Cross-linked polysiloxane stabilized Pt-Nanoparticles
Detailed NMR studies were carried out to establish the ratios of
1
the isomers. In the H NMR, the vinylic proton of the major
product appeares as singlet peak at 6.05 ppm whereas for other
isomer it was found to be a quartet at 6.8 ppm. Based on the
spin-multiplicity analysis of these peaks, it was concluded that
the major product was one of the
whereas the minor product was an
further distinguish the two isomers, the products were analysed
by 1D NOE techniques. In the case of -isomer a pronounced

- isomers (i.e.

-E or
-Z)

-isomers (i.e -E or

-Z). To

NOE effect was observed between the -Me and –SiMe3 protons
whereas no such effect was observed between the –Me and
vinylic protons. Similarly, in case of the -isomer a strong NOE
was again observed between -Me and –SiMe3 protons but no
such effect was there between the –Me and -SiEt3 proton. In
order to show an NOE effect, both -Me and –SiMe3 protons need
At this juncture, the TEM analysis was carried out to
authenticate the formation of Pt-nanoparticles. The TEM
analysis indicated presence of spherical metal nanoparticles
with an average particle size of 2 nm. After verifying the
presence of Pt-nanoparticles in the solution, the reaction flask
was exposed to air. Further stirring of the solution in air yielded
a black gummy solid. We assumed and later confirmed that this
gummy solid was formed due to the oxidative coupling of the
remaining silicon-hydrogen bonds in presence of oxygen to
furnish cross-linked polysiloxane stabilized platinum
nanoparticles in the powder form.
The resulting solid was thoroughly washed with benzene (100
mL) to remove any impurities. Air-drying of the solid furnished
the polysiloxane conjugated Pt-nanoparticle catalyst as a black
powder. The NMR, SEM and Elemental analyses of powder form
of the catalyst have revealed that the material has a composition
containing about 5% platinum metal uniformly dispersed in
cross-linked polysiloxane. In the XPS spectra of the solid powder,
two broad bands appear which correspond to the Pt4f7/2 and
Pt4f5/2 levels. The Pt4f7/2 peaks were deconvoluted into two
components and found to be at 72.75 and 75.5 eV respectively
which is in good agreement with reported results for binding
energy of Pt-Si bonds and in zero oxidation state of platinum.26
The initial investigations of catalytic activity of Pt-nanoparticles
towards the hydrosilylation of alkyne were carried out using
trimethylsilyl-1-propyne (Scheme 3). In the presence of catalytic
to be within a close proximity which was only met in
E isomers. These results confirmed the structure of major
product as a -E isomer and the minor product as -E isomer.
-E and -


A series of organosilanes containing different substituents on
the silicon were employed as hydrosilylating agent for
examining the scope of the preliminary findings. All reactions
were carried out at room temperature using equimolar amount
of silane and alkyne in presence 0.1 mol% with respect to alkyne.
After completion of the reaction, the product was isolated from
the catalyst by centrifugation while the precipitated catalyst was
washed with hexane and re-used for next cycles of reaction. The
identification of different isomers was made based on the
analysis of spin-multiplicity, proton-proton coupling constant (J)
values and Nuclear Overhauser effect (NOE) obtained from the
1H NMR studies of the isolated product. The distribution of
different isomers in the product was calculated using
quantitative 1H and 29Si NMR spectroscopic techniques. Results
are shown in Table 1.
The alkoxy- and chloro- substituted silanes (Entry 2b-f, Table 1)
were reacted with trimethylsilyl-1-propyne under similar
reaction conditions and molar ratios. The substitution of alkoxy
and chloro groups on hydrosilane (2b-f) had a very positive
impact on the selectivity towards
reaction of trimehylsilyl-1-propyne (
to the quantitative formation of
-E isomer. To our surprise
1
) with hydrosilanes 2b-f led

-E isomer. Out of three other
2 | J. Name., 2012, 00, 1-3
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Table 2: Hydrosilylation of disubstituted alkyne using Triethyl silanea
possible isomers, no other isomer was observed. Such a
selectivity with alkoxy- and chloro- functionalities bodes really
well for vinyl silane application because these silanes can further
undergo various transformation to produce intermediates and
precursors to high end materials for various applications.
View Article Online
DOI: 10.1039/C7DT00544J
Isolated
Alkyne
R1
R2
Selectivity‡
-E: -E
6a:7a (85:15)
-
6c:7c (87:13)
6d:7d (54:46)
Yield (%)
96
NR
97
98
5a
5b
5c
5d
SiMe3
SiMe3
SiMe3
C6H5
C6H5
1-Cyclohexenyl
Cyclopropyl
Me
Table 1. Hydrosilylation of Trimethylsilyl-1-propyne (1) in presence of cross-linked
polysiloxane stabilized platinum nanoparticlesa
aAlkyne (1.0 mmol), silane (1.0 mmol), polysiloxane stabilized Pt-nanoparticles (5
mg, 0.1 mol% of Pt), Benzene (2.0 ml), RT; See ‡ for NMR data.
‡
Silane
R1
R2
R3
Isolated
Yield (%)
Selectivity
-E: 
2a
2b
2c
2d
2e
2f
Et
OEt
OEt
Cl
Cl
Cl
Et
Me
OEt
Me
Cl
Et
Me
OEt
Me
Et
98
98
97
98
98
95
3a:4a (91: 9)
Since, it is well known that the silanes bearing electron-
withdrawing groups undergo oxidative addition more efficiently
than those bearing electron-donating groups, an electron
withdrawing group substituted silane dimethylchlorosilane 2d
was investigated as reactant. As we expected, the
3b:4b (100: 0)
3c:4c (100: 0)
3d:4d (100: 0)
3e:4e (100: 0)
3f:4f (100: 0)
Cl
Cl
hydrosilylation reactions of acetylenes 5a-d, produced
-E
aTrimethylsilyl-1-propyne (1.0 mmol), silane (1.0 mmol), polysiloxane stabilized Pt-
nanoparticles (5 mg, 0.1 mol% of Pt), Benzene (2.0 ml) and r.t.; See ‡ for NMR data
isomer in more than 90 % yield. The same trend was observed,
when disubstituted acetylenes 5a and 5b, were subjected to
hydrosilylation reaction with dimethylchlorosilane 2d. Exclusive
To further explore the scope of the present catalysis, various
functionalized alkynes were subjected to the hydrosilylation
reaction. Unless mentioned otherwise, all reactions were
carried out at RT using equimolar amounts of silane and alkyne
in presence of 0.005 g of polysiloxane stabilized platinum
nanoparticles (0.001 mmol of Pt, 0.1 mol% with respect to
alkyne).
formation of
(table 3).
-E isomer was observed in quantitative yield.
Scheme 5: Hydrosilylation of disubstituted alkyne using Dimethylchlorosilane.
All alkynes underwent Pt-nanoparticle catalyzed hydrosilylation
at room temperature to selectively produce corresponding
-E
and -E isomers in 96-98% yield (Scheme 4). Formation of other
two possible isomers (Scheme 1) was not detected in any of the
hydrosilylation reactions. In most cases, relatively higher

Table 3: Hydrosilylation of disubstituted alkyne using Dimethylchlorosilane.
Alkyne
R1
R2
Isolated
Yield (%)
96
Selectivity ‡
-E: 
8a:9a (100:0)
8b:9b (100:0)
8c:9c (98:02)
8d:9d (92:08)
selectivity towards -E over the Eisomer was observed.
Since, the hydrosilylation with triethylsilanes is known to be
sluggish and produce mixtures, the hydrosilylation reactions of
triethylsilane with disubstitutedacetylenes were examined to
access the efficacy and selectivity of present catalyst.
5a
5b
5c
5d
SiMe3
SiMe3
SiMe3
C6H5
C6H5
1-Cyclohexenyl
Cyclopropyl
Me
98
98
98
In order to elucidate the electronic and steric implications of the
substituent present on alkyne moiety, disubstituted alkynes
with four possible combination of substituents including -SiMe3
/-C6H5 (entry 5a, Table 2), -SiMe3/1-Cyclohexenyl (entry 5b), -
SiMe3/1-Cyclopropyl (entry 5c), and -C6H5/-Me (entry 5d,) were
subjected to hydrosilylation reaction under the present catalytic
conditions. It was quite interesting to note that whereas all the
substituents combination smoothly underwent selective
hydrosilylation, the alkyne containing -SiMe3/1-Cyclohexenyl
substituents (5b) did not show any reactivity towards the
present catalytic system. As is evident from the table 2, in most
aAlkyne (1.0 mmol), silane (1.0 mmol), polysiloxane stabilized Pt-nanoparticles (5
mg, 0.1 mol% of Pt), Benzene (2.0 ml), RT; See ‡ for NMR data.
Similar effects were also noticed while performing the
hydrosilylation of phenylacetylene with functional silanes
(Scheme 6). In these cases, the selectivity towards -E isomer
was improved from 87% upto 100% when a chlorosilane was
used (2d, 2f, Table 4). It is worthwhile mentioning that
hydrosilylation of phenylacetylene was reported to give
polyphenylacetylene as undesired side-product,19 whereas
under the present catalytic conditions the phenylacetyne was
selectively converted to corresponding vinylsilane without the
formation of any side-product. From synthetic perspective, the
predictable selectivity, moderate reaction conditions and
functional group tolerance are quite notable features of this
catalysis.
cases a mixture of
cases, except entry 5d, the regioselectivity is favored towards
formation of -E isomer.
-E and -E isomers was observed. In most

Scheme 4: Hydrosilylation of disubstituted alkyne using Triethyl silane.
0.1% Pt-Nano
Benzene/RT
Et3Si
R1
H
H
SiEt3
R2
R1
R2
Scheme 6: Hydrosilylation of phenylacetylene with various functional silane
+
R2
R1
HSiEt3
7a-d 
6a-d -E
5a-d
2a
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Table 5: Hydrosilylation of functional monosubstituted alkyne with Triethylsilane
Acetylene
R3
Isolated
Yield (%)
Selectivity‡
-E: -E
Table 4: Hydrosilylation of phenylacetylene with various functional silanea
13a
13b
13c
4-C6H4F
95
98
98
96
96
14a:15a (85:15)
14b:15b (88:12)
14c:15c (84:16)
14d:15d (85:15)
14e:15e (89:11)
4- C6H4(OMe)
4- C6H4Me
4- C6H4NH2
CH2CH2CH2CN
Silane
R1
R2
Et
R3
Et
Isolated
Yield (%)
98
Selectivity ‡
-E: 
11a:12a (87: 13)
11b:12b (100:0)
11c:12c (100:0)
13dc
13ec
2a
2d
3f
Et
Cl
Cl
13fc
13gc
CH2NEt2
COOH
96
96
14f:15f (92:08)
14g:15g (30:70)
Me Me
Cl Cl
98
98
aAlkyne (1.0 mmol), silane (1.0 mmol), polysiloxane stabilized Pt-nanoparticles (5
aAlkyne (1.0 mmol), silane (1.0 mmol), polysiloxane stabilized Pt-nanoparticles (5
mg, 0.1 mol% of Pt), Benzene (2.0 ml) and RT; See ‡ for details and NMR data.
mg, 0.1 mol% of Pt), Benzene (2.0 ml) and r.t.; See ‡ for NMR data
In order to further scrutinize the scope and new opportunities
for generating functionalized vinly silanes the hydrosilylation
reactions of various functional acetylenes were performed. In
these investigations, one of the sluggishly reacting silane was
used for all the transformation. First experiments were carried
out with aromatic acetylenes (R3=para-X-C6H4-) bearing a
substituent at para-position of the aryl ring (Scheme 7).
One of the important feature of the present catalysis is the
recyclability of the nanoparticle catalysts. In order to scope and
study the limitation, hydrosilylation of 4-methylphenyl
acetylene with triethylsilane was examined under standard
reaction protocols (see supplementary materials). To our
delight, quantitative conversion was recorded in the
hydrosilylation of 4-methylphenyl acetylene with triethylsilane
using recycled a platinum nanoparticle catalyst up to five
consecutive runs with no significant loss in the catalytic activity.
The in-situ UV-vis experiment for all the catalyst cycles resulted
in a featureless spectra indicating the fact that Pt-nanoparticles
were involved in each cycle of the catalysis. It was also evident
from the ICP analysis of hydrosilylated products that the amount
of leachable platinum found in the product was in the range
between 0.01-0.5 ppm.
Scheme 7: Hydrosilylation of functional monosubstituted alkyne with Triethylsilane
In this series of acetylenes, we observed that the -E:  ratio was
In view of extending the present protocol towards the large
scale applications the above reaction was tested in various
solvents including benzene, toluene, xylene and hexane where
no change in reactivity as well as selectivity was detected.
The exact nature of the catalyst was established via controlled
poisoning experiments where a series of hydrosilylation
reactions were performed in the presence of a ligand that is
capable of forming strong coordination bond with the metallic
surface preventing the reactant molecules to approach
nanoparticle surface. Various coordinating ligands have been
reported to be used as an effective surface stabilizing agents for
the synthesis of stable metal nanoparticles.27-28
only slightly influenced by the nature of the substituents at the
para position of the aromatic ring. For example, an electron
withdrawing -OMe group at the para position of aryl ring
furnished 88% selectivity towards
electron-donating -Me and –NH2 groups were found to be 84% and
85% selective toward -E isomer (Table 5).
-E isomer whereas the

Similar observations were also noted in the case of
hydrosilylation of terminal aliphatic alkyne possessing different
functional moieties. Thus, the hydrosilylation of 5-cyanopentyne
(13e, Table 5) produced corresponding -E isomer with 87%
selectivity whereas the diethylamino 2-propyne afforded
isomer with 92% selectivity (13e, Table 5).
-E
In order to investigate the nature of the catalyst during the
catalysis, hydrosilylation of trimethylsilyl-1-propyne with
triethylsilane (scheme 2) was selected as standard reaction.
Thus, under standard reaction conditions, transmission Electron
Microscopic (TEM) and UV-vis studies were performed in
combination with quantitative poisoning studies. Thus, during
the catalysis (silane 2a, scheme 2) one drop of crude reaction
mixture was deposited on formvar/carbon-coated copper grid
and analyzed by TEM, which showed the presence of Pt-
nanoparticle in the size regime of 2-3 nm. The reaction was also
monitored by UV-visible spectroscopy at regular intervals and
It is worth noting that the only exception in all the acetylenes,
which were studied, was the hydrosilylation studies of the
propiolic acid (13g, table 5). In this case our catalysts showed
inverse selectivity by furnishing the sterically unfavorable

isomer over the -E isomer (Entry 15, Table 5). It is also

noteworthy that no dehydrocoupling reaction involving the
silane and carboxylic acid moiety was detected during the
hydrosilylation of the propiolic acid. It is important to mention
that though almost all the alkynes underwent room
temperature hydrosilylation reaction under the present
nanoparticle catalysis, some alkynes especially those
functionalized with a coordinating group such as -(CH2)4CN, –-
showed featureless spectra,
nanoclusters.5d
a
characteristic of Pt-
o
C6H4NH2, -CH2NEt2 and –COOH required heating at 70 C for a
little bit longer reaction time (20h) to provide 100% conversion.
4 | J. Name., 2012, 00, 1-3
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Additional poisoning experiments were performed to further Acknowledgement: Thanks are due to Center foVrieEwnAgrtiicnleeOenrleinde
support the nanoparticle catalysis where
series of Polymeric Materials of City University of DNOeIw: 10Y.1o0r3k9/fCo7rDsTt0u0d5e4n4Jt
a
hydrosilylation reactions were performed in the presence of a support to (AS) at the preliminary stage of this work. We would
coordinating ligand such as pyridine that is capable of forming also like to acknowledge Ms. Katrina E. Caroccia for her
strong coordination bond with the metallic surface preventing participation in the early stages of this work.
the reactant molecules to approach nanoparticle surface. In a
typical procedure, a standard hydrosilylation (entry 13c, table 5)
was performed in three different schlenk tubes in presence of
Notes and references
‡ Typical procedure for Pt-nanoparticle catalyzed hydrosilylation
of alkyne. A Schlenk tube was charged with Pt-nanoparticle
catalyst (0.005g, 0.001 mmol of Pt) and flushed thoroughly with
nitrogen. To this solid catalyst, benzene (2 ml), alkyne (1 mmol)
and silane (1.0 mmol) were added consecutively and the resulting
mixture was stirred at room temperature. Within a period of 30
minutes the solid catalyst was gradually disperse into the reaction
mixture resulting in an almost homogeneous solution. After the
completion of the reaction (10 hours), the catalyst was
precipitated and isolated by centrifuging the reaction mixture at
about 2000 rpm. On evaporation of the solvent from the
supernatant products were obtained in high yields. The isolated
different amounts of pyridine (0.0005 mmol, 0.001 mmol and
0.002 mmol). The reaction mixtures were monitored using
1HNMR; while we observed significant retardation of catalysis
with 0.5 and 1.0 equivalent of pyridine (0.0005 mmol and 0.001
mmol) and complete retardation was observed with 2.0
equivalent of pyridine (0.002 mmol). An additional poisoning
experiment was performed adding pyridine (0.002 mmol) after
~40 % conversion of the reaction; no reaction was observed
thereafter (figure 1).
Figure 1. Catalyst Poisoning During The Catalysis Using Pyridine.
1
products were characterized by H, 13C and 29Si NMR techniques.
100
80
Spectral signatures of the vinyl silane products reported in this
paper are given below.
3a.
Hz, SiCH2), 0.96 (9H, t, J=7.4 Hz,SiCH2CH3), 1.95 (3H,s,CH3), 6.05
(1H,s,C=CHSiMe3). C(150MHz; CDCl3; CHCl3) 0.3, 1.5, 7.4, 21.7,
142.5, 157.5. Si(120MHz; CDCl3)-11.95, 1.98.
4a. H (600MHz; CDCl3;CHCl3)0.25 (9H, s, SiMe3), 0.72 (6H, q, J=7.4
H(600MHz; CDCl3;CHCl3) 0.21 (9H, s, SiMe3), 0.68 (6H,q, J=7.4
60
2.0 equiv. pyridine added

40
20
0


Hz, SiCH2), 0.99 (9H, t, J=7.4 Hz, SiCH2CH3), 2.01 (3H, d, J=6.7 Hz,
CH3), 6.80 (1H, q, J=6.7 Hz, C=CHMe).
0
200
400
600
800
1000
1200
3b.
SiMe2OEt), 1.04 (3H, t, J=6.9 Hz, OCH2CH3), 2.78 (3H, s,CH3), 3.49
(2H, q, J=6.9 Hz, SiCH2CH3), 6.0 (1H, s, C=CHSiMe3). C(150MHz;
CDCl3; CHCl3) -2.9, -0.07, 18.3, 20.2, 58.2, 142.7, 157.8.
Si(120MHz;CDCl3)-11.31, 5.58.
3c. H (600MHz; CDCl3;CHCl3) 0.08 (9H, s, SiMe3), 1.17 (9H, t, J=6.9
Hz, OCH2CH3), 1.86 (3H, s, CH3), 3.77 (6H, q, J=6.9 Hz, OCH2CH3),
H (600MHz; CDCl3;CHCl3) 0.05 (9H, s, SiMe3), 0.28 (6H, s,
Time (min)


Conclusions

In this paper, a mild, predictable, facile and widely applicable Pt-
based recyclable platinum nanoparticle catalyzed selective
hydrosilylation of mono- and di-substituted alkynes is reported.
A variety of hydrosilanes were selectively reacted with alkynes
6.32 (1H, s, C=CHSiMe3). C(150MHz; CDCl3; CHCl3)-0.1, 18.2, 20.7,
58.5, 147.3, 150.2.
3d. H(600MHz; CDCl3;CHCl3) 0.14 (9H, s, SiMe3), 0.38 (6H, s,
containing diverse functionality including –Me, –C6H5, para - SiMe2Cl), 1.90 (3H, s,CH3), 6.13 (1H, s, C=CHSiMe3).
3e. H (600MHz; CDCl3;CHCl3) 0.13 (9H, s, SiMe3), 1.02 (3H, t, J=7.0
Hz, SiCH2CH3), 1.06 (2H, q, J=7.0 Hz, SiCH2CH3), 1.95 (3H, s, CH3),
6.38 (1H, s, C=CHSiMe3).C(150MHz; CDCl3; CHCl3)-2.7, 6.3, 11.3,
C6H4Me, para-C6H4(OMe), -SiMe3, -(CH2)4CN, -C6H4NH2, -CH2NEt2
and -COOH to furnish corresponding vinylsilanes in high yields.
In situ characterization using UV-vis, Electron Microscopy and
controlled poisoning experiments during the reaction has
revealed the participation of Pt-nanoparticles as an active
catalyst. Whereas, the regio and stereo selectivity of the present
nanoparticles catalyst were not very different for the
hydrosilylation of certain alkynes reported previously,
significant improvement in terms of catalytic efficiency, ease of
catalyst recovery and recyclability over other platinum-based
catalysts were achieved using polysiloxane stabilized Pt-
nanoparticle catalysis. Thus, excellent yields of various
19.3, 148.4, 150.6.
3f. H (600MHz; CDCl3;CHCl3) 0.01 (9H, s, SiMe3), 1.88 (3H, s, CH3),
6.53 (1H, s, C=CHSiMe3). ).C(150MHz; CDCl3; CHCl3)-0.4, 18.5,
147.9, 151.4. Si(120MHz;CDCl3)-8.19, -4.17.
6a. H (600MHz; CDCl3;CHCl3) -0.31 (9H, s, SiMe3), 0.47 (6H, q,
Si(120MHz;CDCl3)-9.27, 17.25.



J=7.6 Hz, SiCH2CH3), 0.78 (9H, t, J=7.6 Hz, SiCH2CH3), 6.1 (1H, s,
C=CHSiMe3) 6.99-7.25 (5H, m, C6H5).C(150MHz; CDCl3; CHCl3)
0.1, 2.8, 7.3, 125.6, 127.0, 127.7, 132.2, 145.9, 163.6.
7a. H( 600MHz; CDCl3;CHCl3) 0.06 (9H, s, SiMe3), 0.16 (6H, q,
J=7.6 Hz, SiCH2CH3), 0.59 (9H, t, J=7.6 Hz, SiCH2CH3), 6.99 -7.25 (5H,
functionalized vinylsilanes (95%) can be achieved by using
m, C6H5), 7.65 (1H, s, C=CHC6H5).
polysiloxane stabilized Pt-nanoparticles providing a significant
cost advantage over homogeneous platinum complexes. Further
research to expand the substrate scope of the present catalysis SiCH2CH3), 1.74 (1H, m, CH), 5.85 (1H, s, C=CHSiMe3).
6c.
CH2CH2), 0.54 (6H, q, J=7.9 Hz, SiCH2CH3), 0.88 (9H, t, J=7.9 Hz,
C(150MHz;
CDCl3; CHCl3) 0.22, 2.58, 4.16, 7.53, 21.81, 128.33, 142.5.
H (600MHz; CDCl3;CHCl3) 0.13 (9H, s, SiMe3), 0.44 (4H, m,

is underway.
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7c. H (600MHz; CDCl3;CHCl3) 0.18 (9H, s, SiMe3), 0.44 (4H, m,
CH2CH2), 0.45 (6H, q, J=7.9 Hz, SiCH2CH3), 0.84 (9H, t, J=7.9 Hz,
SiCH2CH3), 1.19 (1H, m, CH), 5.73 (1H, d, J= 9.8 Hz, C=CHSiMe3).
Journal Name
CHCl3) 3.5, 7.3, 114.7, 120.5, 127.3, 133.2, 144.5, 146.3.

View Article Online
DOI: 10.1039/C7DT00544J

15d.
Si(120MHz;CDCl3) 0.14.

H (600MHz; CDCl3;CHCl3) 0.54 (6H, q, J=8.0 Hz, SiCH2CH3),
6d.
0.95 (9H, t, J=7.6 Hz, SiCH2CH3), 1.60 (3H, s, C=CCH3C6H5), 6.85 (1H, J=3.2 Hz, C=CHH), 5.74 (1H, d, J=3.2 Hz, C=CHH), 6.46 (2H, d, J=8.4
s, C=CHC6H5), 6.97-7.32 (5H, m, C6H5). Hz, C6H4), 6.89 (2H, d, J=8.4 Hz, C6H4).
7d. H (600MHz; CDCl3;CHCl3) 0.73 (6H, q, J=7.6 Hz, SiCH2CH3), 14e. H (600MHz; CDCl3;CHCl3) 0.53 (6H, q, J=7.9 Hz, SiCH2CH3),
0.95 (6H, t, J=7.6 Hz, SiCH2CH3 ), 2.00 (3H, d, , J=2.8 Hz, C=CHCH3), 0.90 (9H, t, J=7.9 Hz, SiCH2CH3 ), 1.76 (2H, quintet, J=7.2 Hz,
H (600MHz; CDCl3;CHCl3) 0.61 (6H, q, J=7.6 Hz, SiCH2CH3), 0.83 (9H, t, J=8.0 Hz, SiCH2CH3), 3.46 (2H, br, NH2), 5.36 (1H, d,


6.10 (1H, q, J=2.8 Hz, C=CHCH3), 6.97-7.32 (5H, m, C6H5).
C=CHCH2CH2), 2.25 (2H, dt, J=7.2 Hz, J=6.3 Hz, CHCH2CH2), 2.30
(2H, t, J=7.2 Hz, CH2CN), 5.63 (1H, d, J=18.7 Hz, SiCH=CHCH2), 5.92
8a. H (600MHz; CDCl3;CHCl3) -0.19 (9H, s, SiMe3), 0.42 (6H, s,

SiMe2Cl), 6.58 (1H, s, C=CHSiMe3), 6.99-7.25 (5H, m, C6H5). (1H, dt, J=18.7 Hz, J=6.3 Hz, SiCH=CHCH2).
C(150MHz; CDCl3;
CHCl3) 3.3, 7.2, 16.2, 24.3, 35.4, 119.5, 128.7, 145.0.

C(150MHz; CDCl3; CHCl3) -0.2, 1.3, 126.4, 127.7, 128.8, 142.7,

Si(120MHz;CDCl3) -1.04.
148.0, 160.8.
Si(120MHz; CDCl3) -8.31, 17.05.
15e. H (600MHz; CDCl3;CHCl3) 0.58 (6H, q, J=7.9 Hz, SiCH2CH3),

8b. H (600MHz; CDCl3;CHCl3) -0.01 (9H, s, SiMe3), 0.30 (6H, s,

0.90 (9H, t, J=7.9 Hz, SiCH2CH3), 1.76 (2H, quintet, J=7.2 Hz,
CH2CH2CH2CN), 2.21 (2H, t, J=7.2 Hz, CH2CH2CH2CN ), 2.30 (t, 2H,
J=7.2 Hz, CH2CH2CH2CN), 5.36 (1H, d, J=2.5 Hz, C=CHH), 5.60 (1H,
d, J=2.5 Hz, C=CHH).
SiMe2Cl), 1.48 (4H, m, C=CHCH2CH2), 1.93 (4H, m, C=CHCH2CH2),
5.16 (1H, s, C=CHSiMe3), 6.09 (1H, m, C=CHCH2CH2).
8c. H (600MHz; CDCl3;CHCl3) 0.09 (9H, s, SiMe3), 0.45 (6H, s,
SiMe2Cl), 0.74 (4H, m, CH2CH2), 1.66(1H, m, CH), 6.32 (1H, s,
C=CHSiMe3).C(150MHz; CDCl3; CHCl3) 0.0, 3.0, 7.2, 16.9, 147.0,
160.0.
14f. H (600MHz; CDCl3;CHCl3) 0.73 (6H, q, J=7.9 Hz, SiCH2CH3),
1.08 (9H, t, J=7.9 Hz, SiCH2CH3), 1.15 (6H, t, J=7.2 Hz, NCH2CH3),
2.69 (4H, q, J=7.2 Hz, NCH2CH3), 3.33 (2H, d, J=5.8 Hz, C=CHCH2N),
5.90 (1H, d, J=18.6 Hz, C=CHSi), 6.25 (1H, dt, J=18.6 Hz, J=5.8 Hz,
8d.
C=CCH3), 6.86 (s, 1H, C=CHC6H5), 7.20-7.32 (5H, m, C6H5).
9d. H (600MHz; CDCl3;CHCl3) 0.40 (6H, s, SiMe2Cl), 1.58 (3H, d,
H (600MHz; CDCl3;CHCl3) 0.55 (6H, s, SiMe2Cl), 1.99 (3H, s,
C=CHCH2N).
C(150MHz; CDCl3; CHCl3) 3.4, 7.3, 11.6, 46.7, 59.3,

128.9, 145.5.
J=6.9 Hz, C=CHCH3), 6.34 (1H, q, J=6.9 Hz, C=CHCH3), 7.20-7.32
(5H, m, C6H5).
15f. H (600MHz; CDCl3;CHCl3) 0.78 (6H, q, J=7.9 Hz, SiCH2CH3),
1.12 (9H, t, J=7.9 Hz, SiCH2CH3), 1.19 (6H, t, J=7.2 Hz, NCH2CH3),
2.56 (q, 4H, J=7.2 Hz, NCH2CH3), 3.17 (2H,s, NCH2C=C), 5.50 (1H, d,
J=3.5 Hz,C=CHH ), 5.95 (1H, d, J=3.5 Hz, C=CHH).
14g. H (600MHz; CDCl3;CHCl3) 0.51(6H, q, J=7.0 Hz, SiCH2CH3),
0.92 (9H, t, J=7.0 Hz, SiCH2CH3), 6.27 (1H, d, J=19.1 Hz, C=CHSi),
7.36 (1H, d, J=19.1 Hz, SiC=CHCOOH), 12.10 (1H, br, COOH)
15g. H (600MHz; CDCl3;CHCl3) δ 0.73(6H, q, J=7.0 Hz, SiCH2CH3),
0.92 (9H, t, J=7.0 Hz, SiCH2CH3), 6.09 (1H, d, J=2.6 Hz, C=CHH), 6.95
(1H, d, J=2.6 Hz, C=CHH), 12.10 (1H, br, COOH).
11a. H (600MHz; CDCl3;CHCl3) 0.58 (6H, q, J=8.0 Hz, SiCH2CH3),
0.91 (9H, t, J=8.0 Hz, SiCH2CH3), 6.35 (1H, d, J=19.7 Hz, C=CHSi)
6.80 (1H, d, J=19.7 Hz, C=CHC6H5), 7.00-7.36 (5H, m, C6H5).
12a. H (600MHz; CDCl3;CHCl3) 0.53 (6H, q, J=8.0 Hz, SiCH2CH3),
0.85 (9H, t, J=8.0 Hz, SiCH2CH3), 5.47 (1H, d, J=2.9 Hz, C=CHH) 5.77
(1H, d, J=2.9 Hz, C=CHH), 7.01-7.35 (5H, m, C6H5).
11b.
J=19.2 Hz, C=CHSi) 7.11 (1H, d, J=19.2 Hz, C=CHC6H5), 7.30-7.50
(5H, m, C6H5). C(150MHz; CDCl3; CHCl3) 2.0, 124.5, 126.8, 128.5,
128.8, 137.1, 146.5. Si(120MHz; CDCl3) 19.47.
11c. H (600MHz; CDCl3;CHCl3) 6.00 (1H, d, J=18.6 Hz, C=CHSi),
6.72 (1H, d, J=18.6 Hz, C=CHC6H5), 7.10-7.42 (5H, m, C6H5).
14a. H (600MHz; CDCl3;CHCl3) 0.83 (6H, q, J=7.8Hz, SiCH2CH3),
1.15 (9H, t, J=7.8Hz, SiCH2CH3), 6.48 (1H,d, J=19.2Hz, C=CHSi), 7.10
H (600MHz; CDCl3;CHCl3) 0.63 (6H, s, SiMe2Cl), 6.50 (1H, d,


1
I. Ojima, Z, Li, J. Zhu, In The Chemistry of Organosilicon
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
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CDCl3) 0.42.
14b. H (600MHz; CDCl3;CHCl3) 0.51 (6H, q, J=7.6 Hz, SiCH2CH3),
0.83 (9H, t, J=7.6 Hz, SiCH2CH3 ), 3.62 (3H, s, C6H4OMe), 6.07 (1H,
d, J=19.6 Hz, C=CHSi), 6.69 (1H, d, J=19.6 Hz, C=CHC6H4), 6.67 (2H,
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15b. H (600MHz; CDCl3;CHCl3) 0.47 (6H, q, J=7.6 Hz, SiCH2CH3),
0.77 (9H, t, J=7.6 Hz, SiCH2CH3), 3.62 (3H, s, C6H4OMe), 5.35 (1H,d,
J=3.1 Hz, C=CHH), 5.70 (1H, d, J=3.1 Hz, C=CHH), 6.93 (2H, d,
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1.26 (9H, t, J=8.0 Hz, SiCH2CH3), 2.59 (3H, s, C6H4Me), 6.63 (1H, d,
J=18.8 Hz, C=CHSi), 7.15 (1H, d, J=18.8 Hz, C=CHC6H4), 7.38 (2H, d,
J=8.4Hz, C6H4), 7.60 (2H, d, J=8.4Hz, C6H4).
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15c. H (600MHz; CDCl3;CHCl3) 0.93 (6H, q, J=7.6 Hz, SiCH2CH3),
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1.20 (9H, t, J=7.6 Hz, SiCH2CH3), 2.59 (3H, s, C6H4Me), 5.82 (1H, d,
J=2.8 Hz, C=CHH), 6.14 (1H, d, J=2.8 Hz, C=CHH), 7.13-7.38 (4H, m,
C6H4).
14d. H (600MHz; CDCl3;CHCl3) 0.56 (6H, q, J=8.0 Hz, SiCH2CH3),
0.87 (9H, t, J=8.0 Hz, SiCH2CH3), 3.46 (2H, br, NH2), 6.05 (1H, d,
J=19.2 Hz, C=CHSi), 6.47 (2H, d, J=8.4 Hz, C6H4 ), 6.68 (1H, d, J=19.2
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C(150MHz; CDCl3;
6 | J. Name., 2012, 00, 1-3
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