A synthesis of a new macromolecular class of vinylene-arylene copolymers with double-decker silsesquioxane in the main chain is presented. Two transition-metal-catalyzed processes, which is silylative-coupling copolycondensation (SCC) and ADMET copolymerization of divinyl-substituted double-decker silsesquioxanes (DDSQ-2SiVi) with selected diolefins, are reported to be highly efficient tools for the formation of stereoregular copolymers containing DDSQ-silylene-vinylene-arylene units. The copolymeric products are studied in terms of their structural, thermal, and mechanical properties. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1044–1055

A new highly selective method for the synthesis of borasiloxanes through the O-borylation of silanols, disilanols, and disiloxanediols with vinylboronates in the presence of Ru⁰ complexes (mainly Ru₃CO₁₂) is described. The method leads to the formation of special compounds with a B–O–Si inorganic framework. When Ru⁰ complexes are used as a catalyst, no vinylboronate homocoupling is observed. A mechanism for this transformation is proposed on the basis of stoichiometric reactions of Ru⁰ with triethylsilanol and vinylboronate.

A series of functionalized dialkenylsilsesquioxanes were obtained by efficient and highly stereoselective silylative coupling and cross-metathesis of divinylsubstituted double-decker silsesquioxanes (DDSQ-2SiVi) with substituted styrenes and other olefins. Both reactions proceed highly stereoselectively and lead to nearly quantitative formation of E isomers. The optimized reaction conditions for styrene were adopted for successful silylative coupling polycondensation of DDSQ-2SiVi with 1,4-divinylbenzene yielding stereoregular cooligomer containing double-decker (silsesquioxyl-silylene)-vinylene-phenylene units.

Ruthenium alkylidene complexes, based on second generation Hoveyda–Grubbs catalysts, have been directly attached to silica through covalent Ru-O-Si bonds, characterized by using cross polarization magic angle spinning ¹³C NMR (CP MAS ¹³C NMR) spectroscopy, and proved active in selected metathetic transformations. The complexes can be easily recycled and subsequently reused. In the ring closing metathesis (RCM) reaction of diethyl diallyl malonate the heterogenized complex can be recycled up to 15 times.

Monovinylheptaisobutylsilsesquioxane undergoes efficient cross-metathesis and silylative coupling with styrenes. Allyl derivatives were successfully tested in cross-metathesis in the presence of first generation Grubbs’ catalyst, while heteroatom-substituted vinyl derivatives (vinyl ethers, 9-vinylcarbazole) efficiently undergo silylative coupling catalysed by ruthenium hydride complexes. Both reactions proceed highly stereoselectively and lead to nearly quantitative formation of E isomers. Only when vinyl ethers are used does the reaction lead to a mixture of stereoisomers. Atmospheric pressure photoionisation has been successfully used for recording mass spectra of the functionalised silsesquioxanes.

Surface rhodium siloxide phosphine complexes have been synthesized directly by condensation of the molecular precursor Rh(cod)(PR₃)(OSiMe₃) [R=Cy (1), Ph (2), iPr(3); cod=1,5-cyclooctadiene] with silanol groups on silica (Aerosil 200) and their structures have been characterized by ¹³C, ²⁹Si, and ³¹P cross-polarization magic-angle spinning (CP/MAS) NMR spectroscopy. Such single-site complexes have been tested for their activity in hydrosilylation of olefins with heptamethyltrisiloxane and poly(hydromethyl-co-dimethyl)siloxane. The immobilized catalysts 1–3 all retained their effectiveness even after recycling up to at least five times and mostly up to ten times. Based on the results of CP/MAS NMR measurements, a mechanism of hydrosilylation catalysis by single-site rhodium siloxide phosphine complexes is proposed, which involves concurrent pathways of oxidative addition and replacement of phosphine by olefins.

A series of substituted vinylgermanes and divinylgermanes have been synthesized in moderate or high yield via two reactions of olefins and dienes catalyzed by [RuHCl(CO) (PCy₃)₂], i.e. germylative coupling with vinylgermanes and dehydrogenative germylation with hydrogermanes. While the former reaction can be a versatile way of regioselective synthesis of products (particularly useful for the stereoselective synthesis of germylsilylethenes), the latter could be used as a complement, especially in synthesis of germylate dioxol ethene and vinyl ethers. Copyright © 2008 John Wiley & Sons, Ltd.