Photochemical Reduction and Oxidation of Cerium(IV) Porphyrin Sandwich Complexes

S. Radzki Dept. of Chemistry, UMCS, Pl. M. Curie-Skłodowskiej 3, 20-031 Lublin, Poland and Ch. Giannotti Institut de Chimie des Substances Naturelles, CNRS, 91198 Gif-sur-Yvette, France

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Irradiation of cerium(IV) complex of octaethyl bisporphyrin Ce[OEP(-2]2 with visible light, in the presence of CCl]4 as an electron acceptor, leads to their photooxidation and π cation radical formation. The process was followed using electron absorption and magnetic circular dichroism spectroscopy. Electronic configuration in neutral mono- and bisporphyrin (sandwich) complexes were compared to the one of the neutral species. Photoirradiation of sandwich octaethyl- and tetraphenyl bisporphyrins, in the presence of an electron donor (triethylamine) results in their photoreduction on different pathways. Formation of the [Ce(III)(TPP)(-2)TPP(-2)]¯ and [Ce(III)(OEP)(-1)(OEP)(-2)] complexes was followed by absorption and electron spin resonance spectroscopy.

DOI: 10.12693/APhysPolA.90.385 PACS numbers: 82.50.Fv