Physical and chemical behaviour of polymeric silicon phthalocyanines

Abstract

A study was made of the formation of silicon phthalocyanine polymers from dihydroxysilicon phthalocyanine (HO) 2SiPc in quinoline, sulpholane and nitrobenzene in the presence of dehydrating additives (ZnCl 2, P 2O 5). An oligomer was obtained with a degree of polymerization higher than 10. Electron absorption spectra and the kinetic stability of silicon complexes were examined according to the degree of polymerization. It was found that two different types of polymeric phthalocyanines combined in a polymer chain through benzene rings of phthalocyanine and the central atom of silicon by oxygen bridges behave in diametrally opposite ways in acid media. In the first case the kinetic stability of polymers decreases, while in the second, it increases, compared with the monomer. The intensity of absorption bands in electron spectra decreases for both types of compound in proportion to the increase in the degree of polymerization. a mechanism is proposed for the breakdown of polymers and a silicon phthalocyanine monomer in concentrated H 2SO 4.