Potential Bioactive ligand and its divalent M(II) complexes: Synthesis, Physicochemical characterization, DFT calculations and Biological applications

Abstract

A new series of Zinc, Copper, Nickel and Cobalt coordinated metal complexes have been harvested by newly synthesized bioactive ligand 2-chloro-6-((2,5-dimethoxybenzylidene)amino)-4-nitrophenol (L) derived from 2,5-dimethoxybenzaldehyde and 2-Amino-6-chloro-4-nitrophenol. Synthesized compounds have been spectrochemically characterized by UV-visible, FT-IR, NMR, ESI-MS, Powder-XRD, elemental analysis, molar conductance, and cyclic voltammetry (CV). The chelation of metal ions to bioactive ligand L was confirmed by FT-IR data. Thermogravimetric analysis (TGA) has been used to investigate the thermal stability of synthesized complexes as well as to identify the coordinated and lattice water molecules. Non-electrolytic behavior of synthesized metal complexes was examined by study of molar conductance. Theoretical study has been carried out using the method DFT/B3LYP at basic sets 6-31G for the bioactive ligand L and LANL2DZ for the metal complexes (CoL, NiL, CuL, ZnL) respectively. Molecular Electrostatic Potential (MEP), Mulliken charges, HOMO-LUMO and global reactivity descriptors; chemical hardness (η), chemical potential (μ), global softness (S) and electrophilicity index (ω) have been estimated and correlated with antimicrobial activity. Biological evaluations of syntyhesized compounds exhibited potent antifungal activity against Fusarium Oxysporum and Aspergillus Niger, and antibacterial against Staphylococcus aureus and E.Coli. All the synthesized compounds have also been screened for dye-degradation against methylene blue dye, in which Cu metal complex displayed better activity comparison to others.