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 procduct 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.