Photoinduced Electron Transfer Reactions of Hexarhenium(III) Cluster: Oxidative Quenching of [Re6S8Cl6]4− Emission by Electron Acceptors

The photoredox ability of a hexarhenium(III) cluster, [Re6(μ3-S)8Cl6]4−, in acetonitrile was examined on the basis of the emission quenching experiments of the cluster by a series of neutral organic electron acceptors (A). The photoinduced electron transfer quenching rate constants and the relevant activation parameters demonstrated that the hexarhenium(III) cluster acted as a useful photoredox sensitizer towards various A and the system gave a high charge separation yield owing to electrostatic repulsion between the product ions: [Re6(μ3-S)8Cl6]3− and A−. These results were proved explicitly by nanosecond transient absorption spectroscopy.