Exploration on Synthesis, Characterization and Biological Activities of Transition Metal Complexes Comprising Hydroxybenzylideneaminocyclohexylimino-methyl-4,6-dibromophenol Schiff Base Ligand

The development of novel compounds is essential for the discovery of new therapeutic chemopharmaceuticals. We have synthesized a new Schiff base ligand through condensation of 3,5-dibromo-2-hydroxybenzaldehyde with cyclohexane-1,2-diamine and its relevant transition metal complexes with Mn, Fe, Co, Ni, Cu and Zn metal ions. The synthesized ligand and the metal complexes have been characterized by elemental analysis, UV–Vis, FT-IR, ¹H-NMR, ¹³C-NMR spectroscopy and ESI mass spectrometry; these studies revealed that ligand is bonded to the metal ion via two phenolic oxygen and two azomethine nitrogen. SEM-EDX with mapping analyses of zinc metal complex also demonstrated needle-shaped morphology with uniform distribution of elements. Schiff base metal complexes have been screened for their in vitro antimicrobial activities against Escherichia coli and Staphylococcus aureus bacteria as well as Candida albicans and Aspergillus niger fungi. Also, molecular docking studies inferred the possible interaction of the metal complexes that have been computed using the molecular mechanic calculations using the HyperChem 8.03 molecular modeling program to confirm that there exists a favorable interaction between biomolecules and metal complex. The anticancer tests for MCF-7 breast cancer cell lines conducted with Zn (II) metal complex demonstrated its synergistic effect, exemplifying its involvement in stronger anticancer action, and implementing a higher inhibitory efficiency of the IC₅₀ value of 86.68 ± 0.72 μg/ml for MCF-7 cell. As a result, the current study recognizes the potential of the newly synthesized Schiff base-derived complexes as a preclinical therapeutic agent.