Synthesis, structural characterization and properties of the electrocatalyticly prepared hydrogen of 1,2-diarylethylene-1,2- dithiolate nickel complexes with bis(diphenylphosphanyl)amine ligand

Ten nickel complexes bearing 1,2-diarylethylene-1,2-dithiolate and bis(diphenylphosphanyl) amine ligands,(p-XC ₆H ₄N(PPh ₂) ₂) Ni(S ₂C ₂(C ₆H ₄Y-p) ₂) (1:X=Br, Y=CH ₃O; 2:X=Br, Y=CH ₃; 3:X=Br, Y=H; 4:X=Br, Y=Br; 5:X=Br, Y=F; 6:X=F, Y=CH ₃O; 7:X=F, Y=CH ₃; 8:X=F, Y=H; 9:X=F, Y=Br; 10:X=F, Y=F), were synthesized and characterized by elemental analysis, nuclear magnetic resonance spectroscopies, infrared spectra, and ultraviolet-visible absorption spectroscopies. The X-ray single crystal diffraction analysis of 1·DMF showed that the nickel atom is located in the S ₂P ₂coordination environment with an almost perfectly square planar. The electrochemical properties of the complexes in DMF solution and the electrocatalytic hydrogen evolution performance in the presence of trifluoroacetic acid (TFA) were determined by cyclic voltammetry. The research results indicated that the conversion frequencies and overpotentials of the electrocatalytic hydrogen evolution for 0.25 mmol complexes 1-10in the presence of 67.317 mM TFA are 299.3-809.7 mmol ^-1and 0.867-0.995V, respectively.