Hydrosilylation and Related Reactions of Silicon Compounds

Polysiloxanes Grafted with Mono(alkenyl)Silsesquioxanes—Particular Concept for Their Connection

“…When 10 −4 mol of Karstedt's catalyst was exploited, only 50% of Si-H conversion was noted, as well as even longer, i.e., 96 h of reaction time. It might be also the aspect of steric hindrance and closure of the SQ core preventing the effective addition of vinyl moiety into the coordination sphere of Pt (according to the Chalk-Harrod mechanism) [100]. On the contrary, the hydrosilylation of 4-PhT 8 and 5-PhT 8 might also be conducted with lower loading of the catalyst, i.e., 10 −4 mol of (Pt 2 (dvds) 3 ) ( Table 2, entries 9 and 12), but it affects the total reaction time and an additional 72 h apart from 24 h which are required for complete Si-H conversion.…”

“…It is worth mentioning that hydrosilylation may not proceed with a complete selectivity control towards the desired product, i.e., in this system, β-addition product and side reactions may occur, e.g., isomerization of olefin, α-addition product or dehydrogenative silylation [100,108,109]. For the reactions with SQs with an alkenyl chain longer than -vinyl, i.e., for -allyl, -hex-5-enyl and -dec-9-enyl derivatives (3-5RT 8 ), a careful evaluation of spectroscopic analyses (Figures 4 and 5) revealed the presence of by-products (Scheme 2).…”

“…It was monitored with FTIR in situ apparatus ( Figure 2). Moreover, as the hydrosilylation reaction may be accompanied by side-reactions, such as dehydrogenative silylation, isomerization or olefin's hydrogenation, additional studies were undertaken to resolve this aspect using diverse Pt-based catalytic systems [100]. The final products, i.e., the polysiloxanes grafted with mono(alkenyl)silsesquioxanes T 8 @PS were obtained as air-stable organosilicons systems with diverse structures and a morphology dependent on the amount of the SQ attached to the polysiloxane chain as well as the length of the alkyl linker between them.…”

Preparation of Tri(alkenyl)functional Open-Cage Silsesquioxanes as Specific Polymer Modifiers

“…It should be highlighted that the hydrosilylation process might not be selective and side reactions may occur, e.g., the isomerization of olefin, αand/or β-addition products or dehydrogenative silylation products, etc. [49]. For the hydrosilylation of 1,5-hexadiene and 1,9-decadiene, despite >99% consumption of SQ-R-SiH reagent the crude products were accompanied by traces (for 1,9-decadiene) or notable, up to 30% amount (for 1,5-hexadiene) of olefin isomerization products (for possible structures, see Supplementary Materials, Section 3a).…”

A Platinum Molecular Complex Immobilised on the Surface of Graphene as Active Catalyst in Alkyne Hydrosilylation

“…Hydrosilylation of alkynes represents a direct approach for the synthesis of carbon-silicon bonds. [1][2][3][4] These compounds are useful industrial intermediates for the production of silicones, lubricants, coatings and fine chemicals. [5,6] Among all the metals active in hydrosilylation reactions, platinum stands out in terms of activity and selectivity.…”