DISILANYLENEARYLENE OLIGOMERS AND POLYMERS FROM DEHYDROPOLYMERIZATION OF 1,4-RH2SIC6H4SIH2R (R = METHYL, ETHYL, AND HEXYL)

The dehydropolymerization of 1,4-RH2SiC6H4SiH2R (R = Me, Et, hexyl) monomers with CpCp*Zr[Si(SiMe3)3]Me catalyst produces linear RH2Si-(C6H4SiHRSiHR)n-C6H4SiH2R oligomers under mild conditions (room temperature). Further heating of the polymerization mixtures (for R = Me or Et) leads to increases in molecular weight, which appear to result partially from cross-linking reactions that occur by dehydrocoupling of ''backbone'' SiH groups. Eventually, insoluble polymers form at higher conversion. The new materials have been characterized spectroscopically, and by thermal gravimetric analysis. The insoluble (cross-linked) EtH2Si-(C6H4SiHEtSiHEt)n-C6H4SiH2Et polymer gives a much higher ceramic yield (67% to 1100-degrees-C) than do the corresponding, low molecular weight oligomers (35% to 1100-degrees-C for M(w) = 860).