Synthesis, Characterization, and Antimicrobial Activity of New Metal Complexes Derived from 4-chloro-N'-[(E)-(3,5-dichloro-2-hydroxyphenyl) methylidene] benzohydrazide

Abstract

Metal(II) complexes, derived from the ligand 4-chloro-N'-[(E)-(3,5-dichloro-2-hydroxyphenyl)methylidene]benzohydrazide (HCBHDCS), were synthesized. These included elemental analyses, IR, UV-VIS, ¹H and ¹³C NMR, ESR and mass spectroscopy, and magnetic susceptibilities and conductivities measurements. The Fe(II), Mn(II), Cu(II), Co(II), and Mn(II) complexes exhibit a high spin octahedral geometry, Pd(II) is square planar, and Cd(II), Hg(II) and Zn(II) are tetrahedral in nature. The electron spin resonance (ESR) spectrum observed in solid copper(II) complex exhibits distinct characteristics indicative of their specific configurations. This complex possesses a ground state with an axial symmetry type. The obtained values substantiated distorted octahedral geometry, indicating a significant ionic or covalent environment. Values for molar conductance in DMF show complexes' non-electrolytic behavior. To determine their crystal structures, X-ray powder diffraction is used. Antimicrobial activity has been tested in the metal complexes and Schiff's base HCBHDCS ligand. In comparison to regular streptomycin, each combination and ligand has greater antibacterial activity against the bacteria E. Coli. At the same time, C. albicans (MCC 1439) and S. cerevisiae (MCC 1033) show good antifungal efficacy, with growth reduced by more than 90% in response to Mn(II) and Fe(II) complexes, respectively. The in-vitro cytotoxic effects of these synthesized ligands and their complexes were also investigated using the brine shrimp bioassay.