title: E.S.R., magnetic, electronic and superoxide dismutase studies of imidazolate-bridged Cu(II)-Cu(II) complexes with ethylenediamine as capping ligand.
abstract: X-band E.S.R., magnetic and electronic spectra of some imidazolate-bridged homometallic complexes [(en)2Cu-R-Im-Cu(en)2](ClO4)3 where en, ethylenediamine; R-ImH, R = H imidazole (ImH); if R = CH3, 2-methylimidazole (M-ImH) and if R = C2H5, 2-ethylimidazole (E-ImH), and mononuclear complexes [(en)Cu-dien](ClO4)2 and [(en)Cu-PMDT](ClO4)2 where dien, diethylenetriamine; PMDT, pentamethyldiethylenetriamine have been described. Superoxide dismutase (SOD) activity has also been measured and compared with earlier reported complexes. In frozen solution at 77 K, the spectra show axial symmetry with a d(x2-y2) ground state. Difference in lambda(max) between mononuclear and binuclear complexes was found to be approximately 65-75 nm. Magnetic susceptibility and E.S.R. spectral measurements for all these binuclear complexes revealed that the copper(II) ions are involved in antiferromagnetic exchange interactions propagated by the imidazolate bridge.
authors.affiliation: Department of Chemistry, A.P.S. University, Rewa, M.P. 486003, India. rnp64@yahoo.co.uk
authors.forename: R N
authors.initials: RN
authors.lastname: Patel
authors.forename: Nripendra
authors.initials: N
authors.lastname: Singh
authors.forename: K K
authors.initials: KK
authors.lastname: Shukla
authors.forename: V L N
authors.initials: VL
authors.lastname: Gundla
mesh_terms: D001665:Binding Sites; D003300:Copper / Q000737:chemistry*; D004574:Electromagnetic Fields; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D004583:Electrons; D005029:Ethylenediamines / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000737:chemistry*; D020128:Inhibitory Concentration 50; D008024:Ligands; D008280:Magnetics; D008956:Models, Chemical; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry*; D013053:Spectrophotometry; D013482:Superoxide Dismutase / Q000737:chemistry*; D013481:Superoxides / Q000737:chemistry; D013696:Temperature
chemical_list: D005029:Ethylenediamines; D007093:Imidazoles; D008024:Ligands; D009942:Organometallic Compounds; D013481:Superoxides; C031234:ethylenediamine; D003300:Copper; D013482:Superoxide Dismutase