Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1236853 | Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy | 2009 | 6 Pages |
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 â1.4Â V. 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 0.4-1.6Â V. The observed rate constant values for catalysis of the hydrolysis of 4-nitrophenyl phosphate are in the range of 1.36Â ÃÂ 10â2-9.14Â ÃÂ 10â2Â minâ1. 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.
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Authors
S. Sreedaran, K. Shanmuga Bharathi, A. Kalilur Rahiman, R. Suresh, R. Jegadeesh, N. Raaman, V. Narayanan,