SYNTHESIS AND CHARACTERIZATION OF COBALT PHTHALOCYANINES COVALENTLY ATTACHED TO SILICA

We have synthesized cobalt phthalocyanines (PcCo, 4-t-Bu4-PcCO) covale ntly attached to a silica surface. The formation of the sulfonamide li nkage was used as a mode of attachment. The resulting catalysts were e xamined in the reaction of autoxidation of cysteine. The catalytic pro perties of the silica-attached PcCo are compared to those of PcCo in c rystalline, soluble and adsorbed states. It was shown that the method of covalent attachment yields highly active catalysts which are stable under the experimental conditions. The degree of PcCo dispersion in t hese catalysts was found to depend on the hydroxylated structure of Si O2, the structure of the phthalocyanine molecule, and the concentratio n of phthalocyanine in the sample. The structural parameters of the si lica-attached phthalocyanine layers in the samples studied have been e stimated by assuming a correlation between the catalytic activity data and the degree of PcCo dispersion.