End Group Analysis Accounts for the Low Molecular Weight Observed in the 1,3-Divinyltetramethyldisiloxane−Pt Complex Catalyzed Hydrosilylation Copolymerization of α,ω-Dienes and 1,3-Dihydridotetramethyldisiloxane

Abstract

The 1,3-divinyltetramethyldisiloxane−Pt complex (Karstedt catalyst) facilitates copolymerization of α,ω-dienes, such as 1,7-octadiene or 1,5-hexadiene, with 1,3-dihydridotetramethyldisiloxane. Spectroscopic analysis of the copolymers indicates the presence dimethylsiloxy and either 2-octenyl or 2-hexenyl end groups. Apparently, the catalyst not only facilitates the hydrosilylation reaction of 1,3-dihydridotetramethyldisiloxane with terminal C−C double bonds but also catalyzes the isomerization of terminal alkenes to internal alkenes, which are not reactive.

Karstedt Catalyst – Catalyzed stepgrowth co-polyaddition of 1,9-decadiene and 1,1,3,3-tetramethyldisiloxane

“…The process, studied for the first time as early as 1965 [12], is well described and explained in the literature. Sargent and Weber have dealt with the consequences of this C@C isomerization particularly for the maximum achievable chain lengths in equimolar axdiene/A copolymerizations [4,5].…”

“…tetramethyldisiloxane A in refluxing toluene with a Pt/carbon catalyst. Sargent and Weber [4,5] and independently Domenico et al [6] described the synthesis of silalkylenesiloxane copolymers by reacting ax-dienes incl. 1,9-decadiene B with A in equimolar quantities in the presence of a 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex.…”

Careful investigation of the hydrosilylation of olefins at poly(ethylene glycol) chain ends and development of a new silyl hydride to avoid side reactions

“…In 1999, Weber and coworkers attempted to copolymerize α,ω‐diene and 1,3‐dihydridotetramethyldisiloxane by hydrosilylation using the Karstedt catalyst . Although hydrosilylation is known to be a high yielding reaction, the maximum molecular weight they could obtain was only 3100 gmol −1 (determined by GPC MALLS).…”

Three‐dimensional computed tomography in the cardiac catheterization laboratory

“…Silicon/carbon based copolymers namely polycarbosilanes or polycarbosiloxanes have garnered considerable interest due to enhanced materials response i.e., high thermal stability, good electrical resistance, low surface tension, release and lubrication properties, and high hydrophobicity in addition to their application to ceramic precursors 1–6. The synthesis of linear polycarbosilanes was not trivial and main synthetic routes were limited to coupling reactions and ring opening polymerization6; however research conducted by Webber and coauthors7–17 and Interrante and coauthors18–26 allow define some viable synthetic routes.…”