Synthesis, spectroscopic characterization, and antimicrobial activity of cobalt(II) complexes of acetone-N(4)-phenylsemicarbazone: crystal structure of [Co(HL)2(MeOH)2](NO3)2

Abstract

Four Co(II) complexes, [Co(HL)2](OAc)2, [Co(HL)2Cl2], [Co(HL)2(MeOH)2](NO3)2, and [Co2(HL)4(SO4)2] (HL = acetone-N(4)-phenylsemicarbazone) were synthesized and characterized by physicochemical and spectroscopic methods. The magnetic susceptibility measurements indicate that the complexes are paramagnetic with three unpaired electrons. In all the complexes, the semicarbazone is coordinated as a neutral bidentate ligand. The structure of [Co(HL)2(MeOH)2](NO3)2 was confirmed by single crystal X-ray crystallography. The ligand is neutral and bidentate, being coordinated to the cobalt atom through the carbonyl oxygen and the azomethine nitrogen. Intermolecular hydrogen bonding and C–H···π interactions combine to stabilize the crystal structure. The ligand and its two complexes [Co(HL)2Cl2] and [Co(HL)2(MeOH)2](NO3)2 were screened for their antibacterial and antifungal activities using disk diffusion methods.