Synthesis, characterization, and biological evaluation of Ni, Co, and Cu Metal Complexes with Heterocyclic Compounds

Abstract

Two new clinically active Schiff bases and their transition metal complexes were synthesized and studied by different spectroscopic and physicochemical methods like NMR, IR, UV-Visible, ESR, TGA, XRD, mass, elemental analysis, molar conductivity and magnetic character. Synthesized complexes and Schiff bases were assessed for invitro antituberculosis activity for Mycobacterium tuberculosis (ATCC–27294) and for antimicrobial activity against drug resistant ESBL (Extended Spectrum β-lactamase) and MBL (Metallo β-lactamase) producing microbial strains. The biological activity of Schiff base was found to improve in presence of transition metal ions. Among the studied metal complexes, copper complexes displayed superior biological activity against all of the microbial strains. Binary complexes of Cu(II), Ni(II), and Co (II) ions have been synthesized by reacting metal salts with a Schiff base, 2-((E)-(5-methylisoxazol-3-ylimino)methyl)-4-methoxyphenol (MIIMMP) in an alcoholic medium. All the metal complexes and schiff base have been characterized by using elemental analysis, IR, UV-VIS, 1H-NMR, 13C-NMR, Mass, ESR spectral data, magnetic moments, TG, and DTA studies. Based on the analytical, spectral data and molecular modeling studies, Ni (II) and Co (II) metal complexes have octahedral geometry, whereas Cu(II) complex has tetragonal geometry. The antimicrobial and cytotoxic activities of the Schiff base and its metal complexes were studied on bacteria, fungi, and human cervical carcinoma cells (HeLa).