Preparation of substituted network polysilanes by a disproportionation reaction of alkoxydisilanes in the presence of alkoxysilanes

Network methylethoxypolysilanes containing various substituents such as hexyl, phenyl, ethylene, hexamethylene, phenylene, and thiophene groups were prepared by a disproportionation reaction of 1,1,2,2-tetraethoxy-1,2-dimethyldisilane in the presence of the corresponding substituted alkoxysilanes. The reaction was considered to proceed via a silyl anion mechanism. The silyl anion produced from a disilane or a higher homologue attacked the alkoxysilane, and that caused the alkoxysilane moiety to be introduced into the polysilane. The amount of incorporated substituents varied from 3 to 29% of all organic substituents, depending on which alkoxysilane was reacted. The electrical conductivities of some polysilanes were measured, and the polymer with thiophene groups was found to show relatively higher conductivity of 10(-5) Scm(-1) after iodine doping. (C) 1996 John Wiley & Sons, Inc.