MODIFICATION OF POLY(METHYL PHENYLSILANE) BY THE ATTACHMENT OF PI-CONJUGATED SUBSTITUENTS - SYNTHESIS AND PHOTOCHEMICAL STUDIES

Poly(methyl phenylsilane), PMPSi, has been partly chloromethylated and the chloromethylated PMPSi has been formylated via the pyridinium salt and the nitrone (Kroehnke transformation). Subsequently, the aldehyde groups have been converted by condensation with aniline, 4-aminoazobenzene and 4-nitroaniline to the corresponding Schiff bases. Also, the aldehyde groups have been converted to 2,4-dinitrophenylhydrazone groups. The extension of the pi-conjugated system of the phenyl groups by attachment of chromophoric groups does not cause a detectable shift of the u.v. absorption band of the sigma-conjugated backbone. Apart from the formylated derivative, all substituted polysilanes are much less photolabile than the original PMPSi and the partly chloromethylated PMPSi. Emission studies have revealed that the fluorescence of PMPSi is strongly quenched by the attached chromophores.