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以CoCl_2.6H_2O为原料,H_2O_2为氧化剂制备钴(Ⅲ)的赖氨酸(Lys)、半胱氨酸(Cys)配合物。发现溶液pH值对配合物的生成有很大影响,以Lys为配体时,最佳pH值为7.5~8.5;而以Cys为配体时,最佳pH值为8.0~9.5.产物的IR光谱测定表明,两种生物配体均以α-氨基氮原子和羧基氧原子同钴(Ⅲ)键合,Lys中的另一个氮原子和Cys中的硫原子不参加配位。利用分光光度法研究了上述配合物在酸性介质中的离解动力学,发现离解反应呈一级动力学规律,求出离解速率常数和离解反应的活化能。
Cobalt (Ⅲ) lysine (Lys) and cysteine (Cys) complexes were prepared by using CoCl_2.6H_2O as raw material and H_2O_2 as oxidant. It was found that the pH value of the solution had a great influence on the formation of the complex. When Lys was used as the ligand, the optimum pH was 7.5-8.5. When Cys was used as the ligand, the optimum pH was 8.0 ~ 9.5. IR spectroscopy of the product showed that both of the biological ligands were bonded to cobalt (III) with an α-amino nitrogen atom and a carboxyl oxygen atom, and the other nitrogen atom in Lys and the sulfur atom in Cys did not participate in the coordination. The dissociation kinetics of the above complex in acid medium was studied by spectrophotometry. The dissociation reaction showed a first-order kinetic law, and the dissociation rate constant and the activation energy of the dissociation reaction were calculated.