Nickel(II) complex with an asymmetric tetradentate Schiff base ligand: synthesis, characterization, crystal structure, and DFT studies

Abstract

A new asymmetric tetradentate Schiff base, bis(5-methoxysalicylidene)-4-methylbenzene-1,2-diamine), H2L, and its Ni(II) complex were prepared and characterized using elemental analyses (CHN), FTIR, UV–Vis, 1H NMR, and 13C{1H} NMR spectroscopic techniques, and crystal structures of both were determined by X-ray crystallography. For both ligand and Ni(II) complex, density functional theory calculations to find geometry parameters, IR frequencies, electronic properties, and natural bond orbital analysis (NBO) were done with M062X method and Def2-TZVP basis set. All calculated data are consistent with the experiments. NBO data for the Ni(II) complex show that the main type of transition in UV-Vis is interligand charge-transfer, which is assigned as π-π*.