Photoredox and electrochemical reactions of water-soluble gold porphyrins

Abstract

Photoredox and electrochemical reactions of water-soluble gold porphyrins (AuTMPyP, AuTPyP and AuTSPP) have been investigated in aqueous solution. AuTMPyP is the most durable photoredox catalyst for these porphyrins operating through the reductive electron transfer process. Photogenerated AuTMPyP (π-radical anion) is able to reduce water at pH < 4, although it undergoes disproportionation to form a AuTMPyP(phlorin). The AuTMPyP(phlorin) is completely oxidized back to the parent AuTMPyP in the dark with the appropriate oxidant, but does not have sufficient potential for the reduction of water.