用NMR法研究铜(Ⅱ)-氨基酸二元配合物配体交换反应动力学  

KINETIC STUDY ON THE LIGAND EXCHANGE REACTIONS OF COPPER(Ⅱ) COMPLEX COMPOUNDS WITH AMINO ACIDS BY NMR METHOD

作　　者：李跃进[1] 张启衍 陈荣悌[2] 

机构地区：[1]天津师范大学化学系 [2]南开大学化学系,天津300071

出　　处：《无机化学学报》1991年第1期82-87,共6页Chinese Journal of Inorganic Chemistry

基　　金：中国科学院武汉物理研究所资助项目

摘　　要：采用Varian XL200超导核磁谱仪,在200.057MHz和25±0.5℃条件下,测定了水溶液中Cu(Ⅱ)分别与脯氨酸、缬氨酸、α-氨基丁酸、苏氨酸、丙氨酸和甘氨酸配合物的配体交换反应速率常数.根据NMR原理导出了实验线宽与配体交换反应速率常数之间的关系,解释了弛豫时间随配体浓度的变化关系.实验表明,交换反应速率大小顺序与氨基酸配体的空间因素一致,即随氨基酸的碳原子数增加,交换反应速率常数减少.根据实验结果提出涉及三角双锥过渡态的反应机理.The rate constants of ligand exchange reactions of the complexes of copper(Ⅱ) with amino acids in aqueous solution have been determined by proton NMR line broadening studies. The experimental results showed the experimental line width to be linearly proportional to the free-ligand coucentration. The relationship between the line width and the ligand exchange rate constant was derived from NMR theory and kinetic considerations. The order of the exchange rate has been found to be glycine>alanine>threonine>α-NH2-butyric>valine > isoleucine > proline, which is in agreement with the sequence of the dynamic steric effect of these ligands. The mechanism proposed involves a trigonal-bipyramidal transition state.

关 键 词：铜 氨基酸 配合物 动力学 NMR 

分 类 号：O614.121[理学—无机化学]