title: Bivalent transition metal complexes of ONO donor hydrazone ligand: Synthesis, structural characterization and antimicrobial activity.
abstract: Mononuclear transition metal complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with a new hydrazone ligand derived from pyrazine-2-carbohydrazide and 2-hydroxyacetophenone have been synthesized. The isolated complexes were characterized by elemental analysis, spectral and analytical methods including elemental analyses, IR, diffuse reflectance, (1)H-NMR, mass spectra, molar conductance, magnetic moment, ESR, XRD, TG and SEM analysis. From the elemental analyses data, the stoichiometry of the complexes was found to be 1:1 (metal:ligand) having the general formulae [M(HL)(Cl)(H2O)2], [M=Mn(II), Co(II), Ni(II) and Cu(II)] and [M(L)(H2O)], [M=Zn(II) and Cd(II)]. The molar conductance values indicate the nonelectrolytic nature of metal complexes. The IR spectral data suggest that the ligand behaves as tridentate moiety with ONO donor atoms sequence towards central metal ion. The Mn(II), Co(II), Ni(II) and Cu(II) complexes have been assigned a monomeric octahedral geometry whereas tetrahedral to Zn(II) and Cd(II) complexes. The antibacterial and antifungal activities of the ligand and its metal complexes were studied against bacterial species Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, Enterococcus faecalis and Streptococcus pyogenes and fungi Candida albicans, Aspergillus niger and Aspergillus clavatus. The activity data show that the metal complexes have a promising biological activity comparable with the parent ligand against all bacterial and fungal species.
authors.affiliation: Department of Chemistry, Sant Gadge Baba Amravati University, Amravati 444602, MS, India.
authors.forename: Ravindra
authors.initials: R
authors.lastname: Bhaskar
authors.affiliation: Department of Chemistry, Sant Gadge Baba Amravati University, Amravati 444602, MS, India.
authors.forename: Nilesh
authors.initials: N
authors.lastname: Salunkhe
authors.affiliation: Department of Chemistry, Sant Gadge Baba Amravati University, Amravati 444602, MS, India.
authors.forename: Amit
authors.initials: A
authors.lastname: Yaul
authors.affiliation: Department of Chemistry, Sant Gadge Baba Amravati University, Amravati 444602, MS, India. Electronic address: aswaranand@gmail.com.
authors.forename: Anand
authors.initials: A
authors.lastname: Aswar
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D000935:Antifungal Agents / Q000737:chemistry / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D056831:Coordination Complexes / Q000737:chemistry*; D005658:Fungi / Q000187:drug effects; D006835:Hydrazones / Q000737:chemistry*; D008024:Ligands; D013058:Mass Spectrometry; D008670:Metals / Q000737:chemistry*; D015394:Molecular Structure; D012545:Schiff Bases / Q000737:chemistry / Q000494:pharmacology*; D013055:Spectrophotometry, Infrared; D028561:Transition Elements / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D056831:Coordination Complexes; D006835:Hydrazones; D008024:Ligands; D008670:Metals; D012545:Schiff Bases; D028561:Transition Elements
keywords: Biological activity; Complexes; Hydrazone ligand; Spectroscopy