Synthesis of Novel Heteroleptic Oxothiolate Ni(II) Complexes and Evaluation of Their Catalytic Activity for Hydrogen Evolution

Two heteroleptic nickel oxothiolate complexes, namely [Ni(bpy)(mp)] (1) and [Ni(dmbpy)(mp)] (2), where mp = 2-hydroxythiophenol, bpy 2,2?-bipyridine dmbpy 4,4?-dimethyl-2,2?-bipyridine were synthesized characterized with various physical spectroscopic methods. Complex 2 was further by single crystal X-ray diffraction data. The complex crystallizes in the monoclinic P 21/c system its neutral form. catalytic properties of both complexes for proton reduction evaluated photochemical electrochemical studies. different their nature photosensitizers, fluorescein CdTe-TGA-coated quantum dots, tested under conditions. role electron donating character methyl substituents revealed light Thus, catalyst performs better than 1, reaching 39.1 TONs vs. 4.63 3 h, respectively, experiments. In contrast, 1 is more photocatalytically active 2, achieving a TON over 6700 120 h irradiation. This observed reverse activity suggests that HER mechanism follows pathways electrocatalysis photocatalysis.