Photophysical and photochemical properties of the water-soluble porphyrin complexes of metals of the platinum group

Consideration is given to phosphorescence and photochemical properties of the coordination compounds Pt(II), Pd(II), and Rh(III) with three water-soluble porphyrins, i.e., meso-tetrakis (4-N,N,N-trimethylaminophenyl) porphin (H₂TTMAP⁴⁺), meso-tetrakis (4-N-methylpyridyl) porphin (H₂TMPyP⁴⁺) and meso-tetrakis (4-sulfonatophenyl) porphin (H₂TSPP^4-). It is shown that the process of photoreduction by an irreversibly oxidized electron donor (EDTA) proceeds only for the complexes with TMPyP, which is attributed to the strongest oxidative properties of these metal poprhyrins in the triplet excited state. The end products of the photoreduction reaction (metal chlorins and metallophlorin-anions) are established and its possible mechanism is suggested.