Comments on Mechanism of Formation

The reaction pathway followed by the reaction of CH Cl with silicon can be understood by considering the mechanism developed by Klebanski and Fikhtengol ts [51] for the reaction of Si(Cu) with MeCl. The first stage involves adsorption of CH2CI2 molecules on the surface of the catalyst, whereby the CH group and the Cl atom of CH2CI2 are directed towards the Si atom and Cu of the catalyst respectively 

This suggested mechanism clarifies why unbranched carbosilane chains are formed in the reaction with CH2CI2, while chain branching occurs in the reaction involving HCCI3. It is also evident that linear compounds will not form during the reaction of Si with CCl.  

A novel group of carbosilanes is formed in the reaction of (Cl3Si)2CCl2 with silicon (Cu catalyst) in a fluid bed at about 310 °C. Besides of (0138 4 0 the following compounds were isolated [179]. 

Spiro-connected four-membered ring structures with a common carbon atom were obtained. Small amounts of even higher molecular carbosilanes of the same structure type seem also to be present. The isolated compounds form white soluble crystals. 

The formation of carbosilanes through rearrangement reactions using AICI3 is already known. This process is best illustrated by considering the transition of Si—Si—C to 

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