Synthesis, crystal structures and conducting properties of heteroleptic nickel(II) 1,1-dithiolate-bpy/dppe ligand complexes

The rigidity and chelation effect of ligands on the hydrogen evolution reaction catalyzed by Ni(ii) complexes

“…60 The Ni–S bond distances (2.2009(5) and 2.2105(6) Å) and Ni–P distances (2.2108(6) and 2.2082(6) Å) are well within the range expected for square planar Ni complexes. 51,52,61 Similarly, the distance of iron from nickel, 4.157 Å, is within the expected range. The S(1)–Ni–P(1) and S(2)–Ni–P(2) angles show less deviation from 90° than the S(1)–Ni–S(2) and P(1)–Ni–P(2) angles.…”

“…These stretching frequency values are in line with earlier reported values. 47,51,52,58,59 IR spectra of complexes 1 and 2 are shown in Fig. S1 and S2, ESI †…”

“…The synthesis of the ligand began with the abstraction of the methylene acidic protons of 2-(methylene-1,1′dithiolato)-5,5′-dimethylcyclohexane-1,3-dione derivatives using KOH, followed by an in situ reaction with CS 2 similar to the reported literature procedure. 51,52 The heteroleptic complexes 1-3 were prepared by the reaction of a mixture containing equivalent amounts of the potassium salt of the dithiolato ligand and NiCl 2 •6H 2 O in methanol with PPh 3 , DPPF, and DPPE in DCM (Scheme 1), respectively. All complexes were obtained as auburn solids which were stable in air and moisture and melted in the temperature range of 110-190 °C.…”

“…6,46–50 Singh et al have synthesized functionalized heteroleptic Ni( ii ) dithiolate-phosphine-based complexes and studied their ability to catalyse water oxidation (oxygen evolution reaction) 47 as well as investigated their photosensitizing properties 51 and semiconductor behaviour. 52…”

“…6,[46][47][48][49][50] Singh et al have synthesized functionalized heteroleptic Ni(II) dithiolate-phosphine-based complexes and studied their ability to catalyse water oxidation (oxygen evolution reaction) 47 as well as investigated their photosensitizing properties 51 and semiconductor behaviour. 52 In this study, we have synthesized and characterized three heteroleptic Ni(II) complexes with the general formula [Ni(II)L (L′) 2 ], where L = 2-(methylene-1,1′-dithiolato)-5,5′-dimethylcyclohexane-1,3-dione is a common component in all complexes, while L′ varies as PPh 3 (1), DPPF (2), and DPPE (3). The chelation effect of the ligand K 2 L provides stability, while the other ligands, L′, are chosen to explore the steric or geometric effect on the HER activity of the complexes.…”