of their application in the investigations of functional polysiloxanes, cubic oligomeric silsesquioxanes, and spherosilicates prepared by hydrosilylation are presented
(Sect. 12.3). Afterward, the details on incorporation of organic groups into particular compounds and application of spectroscopic methods in the studies are
discussed (Sects. 12.4 and 12.5). Section 12.6 contains concluding remarks.
We hope that this review will be a useful introduction to the chemistry and
spectroscopic properties of polysiloxanes, cubic oligomeric silsesquioxanes, and
spherosilicates for the readers who begin their work on these fascinating compounds. As the summary of recent results, it may also be of interest to other, more
experienced researchers in this field. To the best of our knowledge, this is the first
such review in the literature.
12.2 Hydrosilylation Process
As has been already stated, hydrosilylation is a catalytic reaction which involves
addition of Si–H groups to carbon–carbon, carbon–heteroatom (oxygen, nitrogen),
or heteroatom–heteroatom (nitrogen–nitrogen, nitrogen–oxygen) multiple bonds.
Depending on the reagents, compounds containing Si–C, Si–O, or Si–N bonds are
formed [10].
The first hydrosilylation process was reported by Sommer et al. [16]. It was the
reaction between trichlorosilane (Cl 3 SiH) and oct-1-ene carried out with diacetyl
peroxide as catalyst and yielding trichlorooctylsilane (Cl 3 Si(CH 2 ) 7 CH 3 ).
At present, hydrosilylation of carbon–carbon multiple bonds is an important
method of generating Si–C bonds used in both laboratory and industry [10, 17–19].
Numerous studies employing various hydrosilanes and various alkenes, alkynes, or
their derivatives show that the process can be initiated in different ways. In particular, many early and late transition metals or their compounds are efficient catalysts [10, 17–19]. Two platinum compounds, namely H 2 PtCl 6 and Pt 2 [CH 2 =CHSi
(CH 3 ) 2 O] 3 , should be primarily mentioned here. The former, dissolved in isopropanol, was first described as a hydrosilylation catalyst in 1957 [20], the latter,
prepared by treatment of H 2 PtCl 6 with 1,1,3,3-tetramethyl-1,3-divinyldisiloxane—
in 1973 [21]. They are frequently referred to as Speier’s and Karstedt’s catalysts,
respectively. Addition of a small amount of any of these compounds (usually 5–
10 ppm of Pt) to the reaction medium makes it possible to conduct a great number
of hydrosilylation processes smoothly, with high selectivity, in solution or without
solvent. Because of this, Speier’s and Karstedt’s catalysts are very often used.
Addition of a Si–H group to a carbon–carbon multiple bond may result in two
products: Markovnikov and anti-Markovnikov (a and b, respectively, shown in
Fig. 12.1 for hydrosilylation of carbon–carbon double bonds in polysiloxanes with
hydrosiloxanes). In most cases, b adduct is the dominant one.
It should be noted that in the presence of some catalysts or for some compounds
participating in the process, side reactions may take place during hydrosilylation.
12 Application of Spectroscopic Methods in the Studies …
363
(Sect. 12.3). Afterward, the details on incorporation of organic groups into particular compounds and application of spectroscopic methods in the studies are
discussed (Sects. 12.4 and 12.5). Section 12.6 contains concluding remarks.
We hope that this review will be a useful introduction to the chemistry and
spectroscopic properties of polysiloxanes, cubic oligomeric silsesquioxanes, and
spherosilicates for the readers who begin their work on these fascinating compounds. As the summary of recent results, it may also be of interest to other, more
experienced researchers in this field. To the best of our knowledge, this is the first
such review in the literature.
12.2 Hydrosilylation Process
As has been already stated, hydrosilylation is a catalytic reaction which involves
addition of Si–H groups to carbon–carbon, carbon–heteroatom (oxygen, nitrogen),
or heteroatom–heteroatom (nitrogen–nitrogen, nitrogen–oxygen) multiple bonds.
Depending on the reagents, compounds containing Si–C, Si–O, or Si–N bonds are
formed [10].
The first hydrosilylation process was reported by Sommer et al. [16]. It was the
reaction between trichlorosilane (Cl 3 SiH) and oct-1-ene carried out with diacetyl
peroxide as catalyst and yielding trichlorooctylsilane (Cl 3 Si(CH 2 ) 7 CH 3 ).
At present, hydrosilylation of carbon–carbon multiple bonds is an important
method of generating Si–C bonds used in both laboratory and industry [10, 17–19].
Numerous studies employing various hydrosilanes and various alkenes, alkynes, or
their derivatives show that the process can be initiated in different ways. In particular, many early and late transition metals or their compounds are efficient catalysts [10, 17–19]. Two platinum compounds, namely H 2 PtCl 6 and Pt 2 [CH 2 =CHSi
(CH 3 ) 2 O] 3 , should be primarily mentioned here. The former, dissolved in isopropanol, was first described as a hydrosilylation catalyst in 1957 [20], the latter,
prepared by treatment of H 2 PtCl 6 with 1,1,3,3-tetramethyl-1,3-divinyldisiloxane—
in 1973 [21]. They are frequently referred to as Speier’s and Karstedt’s catalysts,
respectively. Addition of a small amount of any of these compounds (usually 5–
10 ppm of Pt) to the reaction medium makes it possible to conduct a great number
of hydrosilylation processes smoothly, with high selectivity, in solution or without
solvent. Because of this, Speier’s and Karstedt’s catalysts are very often used.
Addition of a Si–H group to a carbon–carbon multiple bond may result in two
products: Markovnikov and anti-Markovnikov (a and b, respectively, shown in
Fig. 12.1 for hydrosilylation of carbon–carbon double bonds in polysiloxanes with
hydrosiloxanes). In most cases, b adduct is the dominant one.
It should be noted that in the presence of some catalysts or for some compounds
participating in the process, side reactions may take place during hydrosilylation.
12 Application of Spectroscopic Methods in the Studies …
363