Photoluminescence Electron-Transfer Quenching of Rhenium(I) Complexes with Organic Sulfides

Electron-transfer(ET) from organic sulfides to excited state rhenium(I)-based heteroleptic tricarbonyl complexes [Re(bpy)(CO)3(py)]+ (I) and [Re(bpy)(CO)3(ind))]+ (II) in acetonitrile solution is facile and luminescence quenching constants, kq, are in the range 105–108 M−1s−1. The detection of the sulfide radical cation in this system using time-resolved absorption spectroscopy is a direct evidence for the ET nature of the reaction. The kq values for the quenching of Re(I)-complexes with organic sulfides are analyzed with a scheme involving rate controlling electron transfer process. The measured rate constants for the electron transfer (ET) reaction are close to the values calculated from Marcus theory.