Synthesis, structure and biomimetic properties of Cu(II)-Cu(II) and Cu(II)-Zn(II) binuclear complexes: possible models for the chemistry of Cu-Zn superoxide dismutase.
Four imidazolate-bridged binuclear copper(II)-copper(II) and copper(II)-zinc(II) complexes viz., [(Bipy)(2)Cu-Im-Cu(Bipy)(2)](ClO(4))(3).CH(3)OH, [(Phen)(2)Cu-Im-Cu(Phen)(2)](BF(4))(3).2CH(3)OH, [(Bipy)(2)Cu-Im-Zn(Bipy)(2)](BF(4))(3), and [(Phen)(2)Cu-Im-Zn(Phen)(2)](BF(4))(3), (Bipy=2,2'-Bipyridyl, Phen=1-10-Phenanthroline and Im=imidazolate ion) were synthesized as a possible models for superoxide dismutase (SOD). Complex [(Bipy)(2)Cu-Im-Cu(Bipy)(2)](ClO(4))(3).CH(3)OH has been structurally characterized. This complex crystallizes in the triclinic space group P1, with the unit parameters a=8.88(5) A, b=13.79(17) A, c=20.18(18) A, alpha=76.424(8)(o), beta=85.888(6)(o), gamma=82.213(7). The metal-nitrogen bond length from 1.972-2.273 A and the distance Cu-Cu is 5.92 A. The five-coordinate geometry about the copper(II) ion is square pyramidal. Magnetic moment and electron paramagnetic resonance (e.p.r.) spectral measurements of the homobinuclear complexes have shown an antiferromagnetic exchange interaction. From the e.p.r. and UV-Vis spectral measurement studies, these complexes have been found to be stable (pH 8.5-10.5 for 1, 10.5 for 2,3 and 8.5 for 4). These complexes catalyse the dismutation of superoxide radical (O(2)(-)) at biological pH. All the observations indicate that these complexes act as good possible models for superoxide dismutase.
Patel
R N
RN
Department of Chemistry, A.P.S. University, Rewa, MP 486 003, India. rnp64@yahoo.co.uk
Singh
Nripendra
N
Shukla
K K
KK
Gundla
V L N
VL
Chauhan
U K
UK
D000818:Animals; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D020134:Catalytic Domain; D002417:Cattle; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004578:Electron Spin Resonance Spectroscopy; D066298:In Vitro Techniques; D008956:Models, Chemical; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry* / Q000494:pharmacology; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013053:Spectrophotometry; D013482:Superoxide Dismutase / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
D000900:Anti-Bacterial Agents; D009942:Organometallic Compounds; D003300:Copper; D013482:Superoxide Dismutase; D015032:Zinc