钴(Ⅱ)—5-取代邻菲咯啉—α-氨基酸形成三元配合物的动力学研究

Kinetic Study on the Formation of Ternary Complexes of Co(Ⅱ)-5-Substituted Phenanthrolines and α-aminoacids

本文采用温度跃迁装置,即T-jump方法研究了钴(Ⅱ)—5—取代邻菲咯啉,—α-氨基酸生成三元配合物的动力学性质、测定了该三元体系在25.0±0.1℃,离子强度为0.1mol·dm^(-3)(KNO_3)水溶液中的反应速率常数.结果表明反应速率常数与5-取代邻菲咯啉的质子化常数之间存在着直线自由能关系.讨论了具有不同取代基配体的电子效应对反应速率的影响,以及d-p反馈π键的强弱与该三元体系反应速控步骤速率常数之间的关系.

Kinetics on the formation of the ternary complexes Co(Ⅱ)-5-substituted phenanthro-lines and α-aminoacids was studied by temperature-jump technique and their formation rate constants were determined at 25.0 ±0.1℃, I=0.1mol · dm-3 KNO3. The results show that linear free energy relationships exist between the formation rate constants of the ternary complexes and the protonation constant of 5-substituted phenanthrolines. The substituents of 5-substituted phenanthrolines influenced the formation rate constants of the ternary complexes. The dependence relationships of the rate constants of rate-determining step with the extent of back bonding were discussed.