Si-B-C-N ceramic precursors derived from dichlorodivinylsilane and chlorotrivinylsilane.: 1.: Precursor synthesis

Dichlorodivinylsilane and chlorotrivinylsilane were used as starting materials for the synthesis of Si-B-C-N-H polymers. They were either reacted with ammonia to yield silazanes or with cyanamide to form silylcarbodiimides. The reactions occurred almost quantitatively. Starting from dichlorodivinylsilane, oligomeric or polymeric compounds were obtained, whereas reaction of chlorotrivinylsilane delivered monomers. The products were polymerized into solid Si-B-C-N-H polymers by the addition of borane dimethyl sulfide leading to an almost complete hydroboration of the vinyl groups. The compounds were characterized by chemical analysis and infrared spectroscopy. Boron-free compounds were further analyzed by nuclear magnetic resonance spectroscopy and partly by gas chromatography-mass spectroscopy studies.