Heteroleptic metal chellates of m-nitrobenzaldehyde benzoylhydrazone and nicotinamide: synthesis, characterization and antibacterial studies
Keywords:
Mixed ligands complexes, Nicotinamide, m-Nitrobenzaldehydebenzoylhydrazone, Antimicrobial activityAbstract
Mixed ligand complexes of m-nitrobenzaldehydebenzoylhydrazone (m-NBH) and nicotinamide (NA), were synthesized and their elemental, magnetic moment, molar conductivity, Fourier Transform Infra-Red (FT-IR)(UV) spectroscopic characterization were carried out. The IR spectra revealed that the VC=O band of the hydrazone shifted in wavenumber from 1654 cm-1 to 1624,1674, 1625, 1622 cm-1 in the Fe-, Co-, Ni-, Cu- complexes, respectively, while the intensity of the VC=N band at 1542 cm-1 decreased. Nicotinamide coordinated via the –N of pyridine, and not through the –NH2 or –C=O groups. The vibrations of M-N and M-O bonds were identified by sharp bands in the range of 426 – 582 cm-1 and 526 – 688 cm-1, respectively. Intra-ligand π→π* and n→π* electronic transitions shifted to lower wavenumbers between 214 - 224 nm and 245 - 262 nm, respectively. For the metal-centered bands, Cu-complex had a broad band around 647 nm. Cocomplex had bands at 505, 645, and 761 nm, and Ni-complex at 654, 721, and 876 nm. Weak bands were observed for the Fe-complex. The molar conductivities of the complexes range from 259 to 331 Ω-1cm2mol-1, indicating their electrolytic nature and the magnetic moment (5.83, 4.30, 2.73, 1.74 MB) showed that the complexes (Fe, Co, Ni, Cu, respectively) were paramagnetic. The stoichiometry ratio of the complexes was 1:1:2 (m-NBH:M:NA). The antibacterial activity of the complexes and ligands was evaluated against fifteen bacteria isolates. There was improved activity by the metal complexes compared to the ligands, except for the Cu-complex.