Preparation, spectral characterization and antimicrobial activity of binary and ternary Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Ce(III) and UO2(VI) complexes of a thiocarbohydrazone ligand

A series of binary complexes of iron(III), cobalt(II), nickel(II), copper(II), zinc(II), cerium(III) and uranyl(VI), have been synthesized by using the organic ligand, H3L, formed by the condensation of thiocarbohydrazide with 2-hydroxy-1-naphthaldehyde. Also, ternary complexes were synthesized by using 1,10-phenanthroline or oxalic acid as a secondary ligand. Characterization and structure elucidation of the synthesized compounds were achieved by elemental and thermal analyses, spectral (IR, electronic, ESR and 1H and 13C NMR), molar conductivities as well as magnetic measurements. The spectroscopic data showed that the ligand acts as a neutral, monobasic or dibasic tetradentate ligand. All the metal complexes exhibited octahedral geometry except cerium(III) and uranyl(VI) complexes in which the metal ions are hepta- and octa-coordinated. The ligand and some metal complexes showed antibacterial activity towards Staphylococcus aureus and Escherichia coli bacteria and antifungal activity towards the fungi Candida albicans and Aspergillus flavus.