A water soluble cocatalyst based on a cobalt(II) complex of S,S’-bis(2-pyridylmethyl)-1,2-thioethane for photochemical driven hydrogen evolution from water under visible light

Abstract The reaction of S,S’-bis(2-pyridylmethyl)-1,2-thioethane (bpte) and CoCl 2 formed a new cobalt(II) complex, [(bpte)CoCl 2 ], a new cocatalyst for photochemical driven hydrogen evolution from water. Several physico-chemical and spectroscopic methods were used to characterize the cobalt complex. Under photoirradiation with blue light (λ max  = 469 nm), together with CdS nanorods (CdS NRs) as a photosensitizer, and ascorbic acid (H 2 A) as a sacrificial electron donor, the cobalt complex can catalyze hydrogen evolution in heterogeneous environments and can remain for 120 h. Under an optimal condition, this photocatalytic system achieved a turnover number (TON) of 9810 mol H 2 per mol of catalyst (mol of cat −1 ) during 95 h irradiation.