Preparation, spectral study and antimicrobial activity of binary Co(II) complexes derived from 2’-hydroxy chalcones

Abstract

ABSTRACT. The present work comprises preparation, characterization, thermal behavior and growth inhibitory activity of some novel Co(II) complexes derived from substituted (E)-1-(1-hydroxy-4-iodonaphthalen-2-yl)-3-phenylprop-2-en-1-one (L1) and (E)-1-(4-bromo-1-hydroxynaphthalen-2-yl)-3-phenylprop-2-en-1-one (L2-L6). Newly synthesized metal-ligand complexes were structurally confirmed with suitable spectroscopic technique such as FT-IR, EPR, NMR (both ¹H and ¹³C). XRD analysis for complex C1 confirmed the crystal system; tetragonal and space group; P 42/n: 2 with unit cell dimensions a, b = 13.3516 Å, c = 10.8009 Å; α, β, γ = 90^o. The IR and EPR study demonstrated that interaction between metal ions and ligand occurs through carbonyl oxygen and hydroxyl oxygen. From the values of magnetic moment (μ) it was observed that synthesized complexes (C1-C6) are paramagnetic with three unpaired electrons contain one electron in t_2g orbital and two electrons in e_g orbitals. Further all these complexes have been evaluated in-vitro for their antimicrobial activity against the Gram positive bacteria Staphylococcus aureus, Gram negative bacteria Escherichia coli and the yeast Candida albicans. The complex C1 showed the significant antimicrobial activity, whereas the complexes C2, C4, C5 and C6 are moderately active against the tested pathogens. The antimicrobial data revealed that growth inhibitory activities of complexes were enhanced comparatively than its respective ligands. The enhanced antimicrobial activity is attributed to the presence of halogens (Br, Cl, I) and hydroxyl (OH) active substituents associated with the basic nucleus of complexes. Therefore, the present study helps to develop a new class of antimicrobial analogues.

KEY WORDS: Metal complexes synthesis, 1,3-Diaryl-2-propene-1-one, Crystal structure, Thermal properties, Antimicrobial activity

Bull. Chem. Soc. Ethiop. 2021, 35(3), 513-524.

DOI: https://dx.doi.org/10.4314/bcse.v35i3.4