Synthesis, crystal structure, spectral characterization, theoretical and computational studies of Ni(II), Cu(II) and Zn(II) complexes incorporating Schiff base ligand derived from 4-(diethylamino)salicylaldehyde

Abstract

Three new nickel(II), copper(II), and zinc(II) complexes were prepared by treating symmetrical tetradentate Schiff base ligand (H2L) with Ni(OAc)2·4H2O, Cu(OAc)2·H2O, and Zn(OAc)2·2H2O salts, respectively. The synthesized compounds were structurally characterized by elemental (CHN) and spectroscopic analysis like FT-IR and 1H NMR. Moreover, the crystal structure of the Ni(II) complex (NiL) has been determined by SC-XRD. The crystal structure investigation confirms that the metal ion is tetra coordinated by ONNO donor sites of ligand to acquire a square planar geometry, which is further compared with some related crystal structures by Cambridge structure database search. A Hirshfeld surface inspection was conducted for the sake of further investigation of the non-covalent interactions in NiL. An enrichment ratio is also calculated for the chemical species to determine the tendency of their interactions in the crystal packing. The theoretical values based on DFT using B3LYP/Def2-TZVP level of theory ensured that the expected consequences matched the experimental findings.