Four new nickel(II) complexes based on an asymmetric Salamo-type ligand: Synthesis, structure, solvent effect and electrochemical property

Abstract

Four new solvent-induced Ni(II) complexes with chemical formulae {[NiL(MeOH)(μ-OAc)]2Ni}·2MeOH (1), {[NiL(EtOH)(μ-OAc)]2Ni} (2), {[NiL(i-PrOH)(μ-OAc)]2Ni} (3) and {[NiL(DMF)(μ-OAc)]2Ni}·2DMF·0.44H2O (4), where H2L=5-methoxy-4′-chloro-2,2′-[(1,3-propylene)dioxybis(nitrilomethylidyne)]diphenol, have been synthesized and characterized by elemental analyses, 1H NMR, FT–IR, UV–Vis spectra and X-ray crystallography. X-ray crystallographic analyses of the Ni(II) complexes reveal that they crystallize in the triclinic system, space group P1¯, and consists of three Ni(II) ions, two deprotonated L2− units, two μ-acetato ligands and two coordinated solvent molecules. In each of the Ni(II) complexes, the Ni(II) ions are hexa-coordinated with a slightly distorted octahedral coordination geometries. Although the molecule structures of the Ni(II) complexes are similar each other, obtained in different solvents, the supramolecular structures are entirely different. The complexes 1 and 3 possess a self-assembled infinite 2D and 1D supramolecular structures via the intermolecular hydrogen bonds, respectively. But the Ni(II) complexes 2 and 4 are formed 0D structures by intramolecular hydrogen bonds. Cyclic voltammetry is used to characterize electrochemical property of the Ni(II) complex 1.