Syntheses, crystal structures, spectral studies, and DFT calculations of two new square planar Ni(II) complexes derived from pyridoxal-based Schiff base ligands

Two new complexes based on a Schiff base derived from pyridoxal N,N-dimethylethylenediamine (HL¹) and N,N-diethylethylenediamine (HL²), [Ni(L¹)SCN] (1) and [Ni(L²)SCN] (2), have been synthesized and structurally characterized by single-crystal X-ray diffraction along with other physical techniques, including elemental analyses, IR spectra, cyclic voltammetry, UV-vis, and luminescence studies. X-ray studies suggest that in both the complexes nickel lies in a slightly distorted square planar environment occupied by the tridentate ONN ligand and an isothiocyanate moiety. Density functional theory computations have been carried out to characterize the complexes.