title: Electrochemical, catalytic and antimicrobial activities of N-functionalized cyclam based unsymmetrical dicompartmental binuclear nickel(II) complexes.
abstract: Five binuclear nickel(II) complexes have been prepared by simple Schiff base condensation of the compound 1,8-[bis(3-formyl-2-hydroxy-5-bromo)benzyl]-l,4,8,11-tetraazacyclotetradecane (L) with appropriate aliphatic or aromatic diamine, nickel(II) perchlorate and triethylamine. All the complexes were characterized by elemental and spectral analysis. Positive ion FAB mass spectra show the presence of dinickel core in the complexes. The electronic spectra of the complexes show red shift in the d-d transition. Electrochemical studies of the complexes show two irreversible one electron reduction processes in the range of 0 to -1.4V. The reduction potential of the complexes shifts towards anodically upon increasing chain length of the macrocyclic ring. All the nickel(II) complexes show two irreversible one electron oxidation waves in the range 0.4-1.6V. The observed rate constant values for catalysis of the hydrolysis of 4-nitrophenyl phosphate are in the range of 1.36x10(-2)-9.14x10(-2)min(-1). The rate constant values for the complexes containing aliphatic diimines are found to be higher than the complexes containing aromatic diimines. Spectral, electrochemical and catalytic studies of the complexes were compared on the basis of increasing chain length of the imine compartment. All the complexes show higher antimicrobial activity than the ligand and metal salt.
authors.affiliation: Department of Inorganic Chemistry, School of Chemical Sciences, University of Madras, Guindy Campus, Chennai 600 025, Tamil Nadu, India.
authors.forename: S
authors.initials: S
authors.lastname: Sreedaran
authors.forename: K Shanmuga
authors.initials: KS
authors.lastname: Bharathi
authors.forename: A Kalilur
authors.initials: AK
authors.lastname: Rahiman
authors.forename: R
authors.initials: R
authors.lastname: Suresh
authors.forename: R
authors.initials: R
authors.lastname: Jegadeesh
authors.forename: N
authors.initials: N
authors.lastname: Raaman
authors.forename: V
authors.initials: V
authors.lastname: Narayanan
mesh_terms: D000935:Antifungal Agents / Q000737:chemistry* / Q000494:pharmacology; D002176:Candida albicans / Q000187:drug effects; D002384:Catalysis; D004563:Electrochemistry; D006571:Heterocyclic Compounds / Q000737:chemistry* / Q000494:pharmacology; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry* / Q000494:pharmacology; D010084:Oxidation-Reduction
chemical_list: D000935:Antifungal Agents; D006571:Heterocyclic Compounds; C024560:cyclam; D009532:Nickel