Photocatalytic hydrogen evolution from a cobalt/nickel complex with dithiolene ligands under irradiation with visible light†
Abstract
Two novel metal dithiolene complexes, namely NtBu4[M(BNT)2] [M = Co/Ni, (BNT = (R)-1, 1′-binaphthalene-2,2′-dithiol)], have been synthesized and characterized. An efficient homogeneous photocatalytic system was constructed by a combination of the noble-metal-free target complexes as water reduction catalysts, xanthene dyes as the photosensitizer and triethylamine (TEA) as the sacrificial electron donor under irradiation with visible light (λ > 420 nm). Maximum H2 evolution of 495 and 676 turnovers (vs. catalyst) were recorded for each catalyst, respectively, under optimal conditions in CH3CN/H2O (1 : 1, v/v) after 4 h of irradiation. Furthermore, the mechanism of the H2 evolution was also briefly discussed alongside fluorescence spectra and cyclic voltammetry studies.