Stoichiometric synthesis structural properties

The examination of structure/property relations of molecular educts and resulting ceramics required the synthesis of stoichiometrically and stmcturally different precursors. A variety of synthesis routes for Si-B-N-C precursors fiom organosilanes, silazanes, and boron compounds have been reported in recent years [3 - 5]. As an example, Riedel obtained a polymeric precursor via hydroboration of methylvinyldichlorosilane and subsequent condensation of the hydroboration product with ammonia (Eq. 1). Pyrolysis led to silicoboron carbonitride ceramics exhibiting thermal stability up to 2000 °C [6]. 

Experimentally, a few series of oligo(l,l-silole)s have been prepared as models of poly(l, 1 -silolejs and their structures and photophysical properties have been studied in detail59,61,62. We have prepared a series of oligo( 1,1 -silolejs 57 having 3,4-diphenyl-2,5-dimethylsilole as a monomer unit. The stoichiometrically controlled reduction of 1,1-dichlorosilole with sodium followed by treatment with 1-methyl-1-chlorosilole affords tersilole57a and quater-silole 57b, as shown in Scheme 1059. Kira and coworkers have reported the synthesis of... 

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