STUDIES ON THE PHOTOCHEMICAL-REACTIONS CA TALYZED BY METALLOPORPHYRINCOMPLEXES .2. AFFECT PHOTOSENSITIZED REACTION BY AROUNDSUBSTITUTING GROUP AND AXIAL COORDINATION OF METALLOPORPHYRIN COMPLEXES

The photosensitized reduction reaction of methylviologen was investiga ted by tetrakis [(4-trimethylamino) phenyl] metalloporphyrins [MeTPI, Me=H-2, Zn(II), Ni(II), Cu(II), Mn(III), Co(III)]. The kinetic paramet er a, inductive time t(i) and initial rate upsilon(o) in photosensitiz ed reaction were applied to measure the photosensitivity of photosensi tizers. Both substituting groups and axial coordinations of metallopor phyrin can exert a great influence on the photosensitivity of photosen sitizers. The experimental results. demonstrated that (1) zinc porphyr in is the best photosensitizers in the same series of porphyrins and m etalloporphyrins; (2) the aromatic organic bases can increase the phot osensitivity through axial ligation, on the contrary, the aliphatic am ines can decrease the photosensitivity; (3) the aromatic organic bases with positive charge can increase the photosensitivity considerably.