Photochemical Properties of Donor-Acceptor Complexes Formed
by Associated Forms of Porphyrin

A.V. Udal’tsov* and A.A. Churin

Faculty of Biology, Moscow State University, Moscow 119899 Russia

Photochemical properties of meso-tetra(p-aminophenyl)porphine associated in the solution and also absorbance and luminescence properties of the porphyrin in thin films and bound to hydrophobic-hydrophilic copolymers were studied using absorbance, luminescence, EPR, and Raman spectroscopy. The results presented here, together with previous data, show that donor-acceptor complexes are formed between associated molecules of the porphyrin both in thin films and in solution. When porphyrin associated in solution is exposed to visible light, generation of radical ions is observed. The corresponding EPR signals are substantially broadened as compared with those of radical cation and anion of meso-tetraphenylporphine. Under action of blue light, a marked decrease in qauntum yield of the radical ions is observed, whereas intensity of vibrational bands of aminoporphyrin in Raman spectra strongly increases as compared to the bands of solvent. These phenomena are explaned by the competition between dissociation of donor-acceptor complex into radical ions and reception of electron excitation by one of the forms of this complex interacting with water.