Syntheses,Characterization and Equilibrium between Mono—and Aqua—bridged Dicobalt(

Syntheses,Characterization and Equilibrium between Mono—and Aqua—bridged Dicobalt（Ⅱ）Complexes.A Structural Model for Methionine

Aminopeptidase

YE,Bao-Hui;CHEN,Xiao-Ming

【期刊名称】《中国化学：英文版》 【年(卷),期】2003(021)005

【摘要】A monomeric complex[Co(Im)2(O2CMe)2](1) and a novel aquabridged dimeric complex [Co2(μ-H2O）（μ-O2CMe)2(Im)4-(O2CMe)2](2)

(Im=imidazole)

have

been

synthesized

and

characterized.Complexes 1 and 2 coexisted in solution.Pure forms of either complex can be obtained from the same solution by controlling the crystallization conditions.All two complexes possess a carboxylate-Im-cobalt(Ⅱ） triad system analogous to the carboxylate-histidine-metal triad systems that have been found in many zinc enzymes and coblat(Ⅱ）-substituted enzymes.In2,two Co2+ ions are conected by a wate nolecule in a bridging fasion with Co……Co[0.3687(1)nm],Co-OH2[0.2159(3)nm],and

Co-OH2-Co[0.3687(1)nm],Co-

OH2[0.2159(3)nm],and Co-OH2-Co[117.2(3)°]，in which the water molecule is further stabilized by two intramolecular hydrogen bonds with the oxygens of the terminal monodentate acetate groups with the distance of 0……0[0.2609(7)nm].The terminal monodentate acetate