UV-LIGHT AND RED-LIGHT CHEMISTRY OF METALLOPHTHALOCYANINE - WAVELENGTH-DEPENDENT PHOTOCHEMICAL REDUCTION OF TETRASODIUM SALTS OF ZN(II) ANDCU(II) TETRASULPHONATOPHTHALOCYANINES WITH AMINES

Irradiation of tetrasodium salts of zinc(II) (Na+,ZnPcS(4-)) and coppe r(II) (Na(4)(+)CuPcS(4-)) tetrasulphonatophthalocyanine in the presenc e of triethanolamine, triethylamine or ethylenediaminetetraacetic acid in degassed aqueous acetonitrile (1:1 by volume) with red fight at 65 6 nm exciting their Q band did not induce any reaction but that with U V light at 365 nm exciting their Soret band led to their reduction. Th e reciprocal quantum yields for photoreduction of ZnPcS(4-) and CuPcS( 4-) on 365 nm excitation increased with increasing concentration of th e amines. The mechanism of the reaction was discussed and participatio n of a higher excited state of the phthalocyanines was suggested.