Cyclopolymerization of 1,1-Dipropargyl-1-silacyclohexane by Transition Metal Catalysts

Abstract

A conjugated spirocyclic polymer was synthesized via the cyclopolymerization of 1,1-dipropargyl-1-silacyclohexane with various transition metal catalysts. The monomer, 1,1-dipropargyl-1-silacyclohexane was synthesized by Grignard reaction of 1,1-dichloro-1-silacyclohexane with propargyl magnesium bromide. This polymerization proceeded well to give the corresponding poly(1,1-dipropargyl-1-silacyclohexane). The catalytic activity of WCl 6 was found to be similar with that of MoCl 5 . The structure of polymer having the conjugated backbone with silacyclohexane moieties was characterized by such instrumental methods as NMR ( 1 H-, 13 C-), IR, and UV-visible spectroscopies. The resulting polymers were mostly yellow or light-brown powders, depending on the catalyst systems used. This polymer was completely soluble in halogenated and aromatic hydrocarbons such as chloroform, 1,2-dichloromethane, benzene, toluene, and chlorobenzene, etc. The thermal and oxidative stabilities of polymer were also studied and discussed.