Synthesis and characterization of two binuclear nickel(II) complexes of thiophenol-based “end-off” compartmental ligands and their application as catalysts for selective oxidation of sulfides

Synthesis, physicochemical, XRD/HSA-interactions, heteromeric [CH···Cl/CH···πPh] synthon, DFT, thermal and 1BNA-DNA molecular coupling of cis-Ni(S, N)2 complex using hydrazine carbodithioate schiff base

The reaction of bidentate-S, N-thione Schiff base ligand, Phenyl (E)-2-(1-phenylethylidene)-hydrazine-1-carbodithioate (PPEHCDT) with NiCl2.3H2O produced a neutral NiII(S, N)2 complex with cis form as kinetic favor isomer. Various physicochemical techniques, including EDX, FAB-MS, UV-Vis, IR, CHN, and XRD-crystal analysis, were employed to characterize the desired complex. These techniques provided evidence supporting the coordination of the ligand with the Ni-center, as indicated by the neutral cis-Ni(L)2 formula. The XRD-results revealed a cis-isomer as anionic S-thiol and bis-bidentate-N-azomethine, as well as a slightly distorted square planar neutral cis-Ni(PPEHCDT)2 complex. In contrast, the DFT simulation supported a distorted tetrahedral as favor geometry, despite the fact that the XRD/DFT structural parameters results agreed. Moreover, the Molecular Electrostatic Potential (MEP) together with the Hirshfeld Surface Analysis (HSA) confirmed the XRD seen in appearance of the Heteromeric sub-synthons via C-H….πPh and C-H···S interactions. Moreover, the TG/DTG technique exhibited a high level of stability (∼ 250 °C) and a two-step thermal degradation process for the prepared cis-Ni(PPEHCDT)2 complex. Furthermore, it has been observed that the molecular docking of 1BNA-DNA with the free ligand is superior to that of the cis-Ni(PPEHCDT)2 complex due to the presence of two H-bonds with a larger binding energy as opposed to a single H-bond with a lower binding energy.