Determination of side products in the photocatalytic generation of hydrogen with copper photosensitizers by resonance Raman spectroelectrochemistry

A combination of UV-Vis and resonance Raman spectroscopy in conjunction with electrochemistry is employed to reveal the nature of a side product formed when using heteroleptic Cu(I)-photosensitizers [(P<<^>>P)Cu(N<<^>>N)](+) for photocatalytic hydrogen generation. It is shown that homoleptic [Cu(N<<^>>N)(2)](+) complexes are formed under oxidative conditions confirming a proposed deactivation pathway.