PREPARATION OF SUBSTITUTED NETWORK POLYSILANES BY A DISPROPORTIONATION REACTION OF ETHOXYDISILANE INITIATED BY A SMALL AMOUNT OF ORGANOLITHIUM REAGENTS

Network methylethoxypolysilanes containing various substituents such a s phenyl, butyl, phenylene, thiophene, and anthracene groups were prep ared by a disproportionation reaction of 1,1,2,2-tetraethoxy-1,2-dimet hyldisilane initiated by addition of a small amount of organolithium r eagents that have the corresponding substituents. The reaction was con sidered to be catalyzed by lithium ethoxide, which was formed by the s ubstitution reaction of the ethoxydisilane with the lithium reagents. Both the substituted and pristine disilanes participated in the dispro portionation reaction to yield the network polysilanes. The amount of the substituents and the molecular weight of the polysilanes varied, d epending on what and how much of the lithium reagent were used. The el ectrical conductivity of some polysilanes was measured, and polymers w ith thiophene or anthracene groups were found to show relatively highe r conductivity of 10(-4) Scm(-1) after iodine doping. (C) 1997 John Wi ley & Sons, Inc.