Synthesis and Functionalization of Hyperbranched Polycarbosilanes

Hydrosilylation, the reaction of hydrosilanes with multiple bonds is one of the most important reactions in silicon chemistry. A specific application is the formation of dendrimeric or hyper-branched carbosilane-based polymers (1). Speier and Karstedt s catalyst can be named as the catalyst used most frequently. The disadvantage of these common catalysts is the numerous side reactions appearing, such as dehydrogenative silylation or a-addition resulting in the undesired Markovnikov product (2). 

The hyperbranched polymers could be functionalized at the remaining double bonds after the polymerization. Further, hydroboration leads to boranes, used as cocatalysts for olefin polymerization (5). Treatment with H2O2 results in terminal hydroxy functionalities, with the addition of chloromethyldimethyl-silane chloromethylsilane endgroups are obtained (4). 

Three-necked 100 mL Schlenk flask, dropping funnel, reflux condenser magnetic stirrer, separatory funnel, flash chromatography, safety glasses, protective gloves, and laboratory coat. 

Magnesium, l-bromo-4-(but-3-enyl)benzene, dichloromethylsi-lane, saturated NH4CI solution, MgS04, dried tetrahydrofuran, pentane, and ethyl acetate. 

The reaction was performed under Schlenk conditions. In a three-necked 100 mL Schlenk flask equipped with dropping funnel and reflux condenser was dispersed 0.49 g (0.02 mol, 

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