title: Synthesis, spectral and oxidase studies of a new diamide copper(II) complex with pendant benzimidazolyl groups.
abstract: A new benzimidazole-based diamide ligand-N,N'-bis(alanine-2-benzimidazolyl) hexanediamide (ABHA) has been synthesized and utilized to prepare Cu(II) complexes of general composition [Cu(ABHA)X2].nH2O,where X is an exogenous anionic ligand (X=Cl-,NO3-). Low temperature EPR spectra has been obtained that shows gparallel>gperpendicular>2.0024, indicating a tetragonal geometry in the solution state. The complexes display a quasi-reversible redox wave due to the Cu(II)/Cu(I) reduction process. E1/2 values shift anodically as NO3-<Cl-, indicating that the bound NO3- stabilizes the Cu(II) ion while the bonded Cl- destabilizes it. The complex [Cu(ABHA)Cl2] has been found to oxidize dopamine to dopachrome or aminochrome, both in a methanolic and a reverse-miceller system. The oxidation of dopamine to aminochrome is reminiscent of the functioning of Prostglandin H-synthetase in brain cells which requires dopamine as a cofactor for catalytic activity.
authors.affiliation: Department of Chemistry, University of Delhi, Delhi 110007, India.
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Upadhyay
authors.forename: Sarita
authors.initials: S
authors.lastname: Tehlan
authors.forename: Pavan
authors.initials: P
authors.lastname: Mathur
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology; D002384:Catalysis; D002413:Cations, Divalent / Q000737:chemistry; D002614:Chelating Agents / Q000138:chemical synthesis* / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D003958:Diamide / Q000138:chemical synthesis* / Q000737:chemistry*; D004298:Dopamine / Q000737:chemistry; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry*; D011451:Prostaglandin-Endoperoxide Synthases / Q000737:chemistry
chemical_list: D002413:Cations, Divalent; D002614:Chelating Agents; D003958:Diamide; D003300:Copper; D010088:Oxidoreductases; D011451:Prostaglandin-Endoperoxide Synthases; D004298:Dopamine