Preparation and degradation of polysilylenes

Abstract

Mechanistic aspects of preparation and degradation of polysilylenes (polysilanes) are discussed. Reductive coupling of disubstituted dichlorosilanes at ambient temperatures in the presence of ultrasound leads to monomodal polymers with relatively narrow molecular weight distributions (Mw/Mn from 1.2 to 1.5) and relatively high molecular weights (Mn from 50,000 to 100,000). Ring-opening polymerization of 1,2,3,4,-tetramethyl-1,2,3,4-tetraphenylcyclotetrasilane initiated with carbanions and silyl anions provides polymers with molecular weights from 10,000 to 100,000 and gives potential possibility of the microstructure control. The dearylation of phenyl containing polysilylenes with triflic acid provides polymers with strong electrophilic silyl triflate moieties. They can react with any nucleophiles such as alcohols, amines, carbanions, organometallics, etc., and produce various functional polysilylenes. Synthesis and solid-state transitions in random copolysilylenes are discussed. Thermal, mechanical, and chemical degradation of polysilylenes is described.