Unsymmetrical Ni(II) Schiff base complex: Synthesis, spectral characterization, crystal structure analysis, Hirshfeld surface investigation, theoretical studies, and antibacterial activity

A new nickel(II) complex (NiLUns) is synthesized by the reaction of unsymmetrical tetradentate salophen-based Schiff base (H2LUns) with Ni(CH3COO)(2)center dot 4H(2)O. The different techniques, like elemental analysis (C, H, and N), FT-IR, UV-Vis, and NMR (H-1 & C-13), were used for structural elucidation of the H2LUns and NiLUns complex. The crystal structure of the nickel complex was studied in detail with the help of the X-ray diffraction technique. It was revealed from the diffraction data that the ligand chelates the Ni(II) ion by using its ONNO set of donor sites and forms a square planar geometry. The different types of strong as well as weak intermolecular interactions were explored with the help of Hirshfeld surface investigation. The theoretical parameters of the optimized structures were calculated by the DFT employing the B3LYP/Def2-TZVP level of theory. Furthermore, the synthesized NiLUns complex was screened against four different bacterial strains to evaluate its biocidal potential, which revealed that metal chelate is slightly more active than the free ligand. The synthesized NiL(Uns )complex is novel concerning its spectroscopic analysis, diffraction studies, theoretical investigation, and antibacterial screening. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

A new nickel(II) complex was synthesized and characterized. The crystal structure of the complex revealed a specific coordination geometry between the ligand and the nickel ion. Theoretical calculations and antibacterial screening demonstrated the potential biocidal activity of the synthesized complex.