论文部分内容阅读
A monomeric complex [Co(Im) 2(O 2CMe) 2] (1) and a novel aqua bridged dimeric complex [Co 2(μ H 2O)(μ O 2CMe) 2(Im) 4 (O 2CMe) 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 cobalt(II) substituted enzymes. In 2, two Co 2+ ions are connected by a water molecule in a bridging fashion with Co…Co [0 3687(1) nm], Co—OH 2 [0 2159(3) nm], and Co OH 2 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 O…O [0 2609(7) nm]. The terminal monodentate acetate groups display quite abnormal geometry due to the strong “pulling effect” on the carboxylates by intermolecular and intramolecular hydrogen bonds. Complex 2 showed weak antiferromagnetic coupling at low temperature with g =2 22 and J =-1 60 cm -1 .
A monomeric complex [Co (Im) 2 (O 2 CMe) 2] and a novel aqua bridged dimeric complex [Co 2 (μ H 2O) (μ O 2 CMe) 2 (Im) 4 (O 2 CMe) 2] 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) (2) (Im = imidazole) have been synthesized and characterized. Complexes 1 and 2 coexisted in solution. triad system analogous to the carboxylate histidine metal triad systems that have been found in many zinc enzymes and cobalt (II) substituted enzymes. In 2, two Co 2+ ions are connected by a water molecule in a bridging fashion with Co ... 0 3687 (1) nm], Co-OH 2 [0 2159 (3) nm], and Co OH 2 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 O ... 0 [0 2609 (7) nm]. The terminal monodentate acetate groups display quite abnorma Complex due to the strong “pulling effect” on the carboxylates by intermolecular and intramolecular hydrogen bonds. Complex 2 showed weak antiferromagnetic coupling at low temperature with g = 2 22 and J = -1 60 cm -1.