Synthesis, crystal structure, evaluation of biological activity and docking study of a novel Schiff base complex bis(2-{[(2-methylpropyl)imino] methyl}phenolato) zinc (II)

Even at low concentrations, several transition metal-based drugs can be harmful to the body, causing consequences such as nephrotoxicity, myelosuppression, and neurotoxicity. Zinc (II) complexes in general exert low toxicity and fewer side effects when compared to other metal-based drugs. A new Schiff base complex, bis(2-{[(2methylpropyl)imino]methyl}phenolato) Zinc (II), was synthesised by a one-pot synthesis method using 2hydroxybenzaldehyde, isobutylamine, and zinc acetate. It was subjected to elemental analysis and spectral characterisation such as UV-vis, FTIR, and 1 H, 13 C NMR. The monomeric mass (m/z = 417 g/mole) in the solid state was measured by mass spectrometry (MS). The complex was thermally stable, resulting in a nil residue at 340 degrees C in a single-step decomposition. It was found to show a sharp melting at 206 +/- 2 degrees C. The single crystal Xray diffraction (XRD) study revealed a tetragonal crystal system with distorted tetrahedral geometry. Hirshfeld surface analysis (HAS) showed the H & ctdot;H, interatomic contact is the largest contributor to crystal packing with 68.7 % with other interactions such as C & ctdot;H (22.2 %), and O & ctdot;H (8.2 %). The zinc complex showed good antibacterial activity with the zone depth (mm) and minimum inhibitory concentration (mu g/mL) for the bacterial strains Escherichia coli (20; 300), Pseudomonas aeruginosa (22; 400), Staphylococcus aureus (21; 400) and Bacillus cereus (23; 400). The zone depth (mm) and MIC (mu g/mL) for antifungal activity were Candida albicans (19; 300), Aspergillus niger (20; 400), Aspergillus flavus (22; 400), and Candida tropicalis (21; 400). The IC50 values for MCF7 and A549 were found to be 37.6 and 33.2 mu g/mL respectively. The docking study showed a higher binding affinity of-9.15 kcal/mol for the species S. aureus (PDB:2W9H).