镉（Ⅱ）、钴（Ⅱ）与某些氨基酸配合物的稳定性与配体碱强的直线自由能关系

Linear Free Energy Relationship between Stability of Coordination Compounds of Cd(Ⅱ),Co(Ⅱ)with Amino-acids and Base Strength of ligands

用电位ｐＨ法测定了二元配合物ＭＬ和ＭＬ＿２（其中Ｍ＝Ｃｏ￣（２＋）、Ｃｄ￣（２＋），Ｌ＝甘氨酸（ｇｉｙ￣－）、丙氨酸（ａｌａ￣－）、缬氨酸（ｖａｌ）、亮氨酸（ｌｅｕ）、笨丙氨酸（ｐｈｅ）、色氨酸（ｔｒｙ））在３７℃、μ＝０．０２（Ｎａｃｌ）条件下的稳定常数和相应的各配体的质子化常数。发现配合物的稳定性（ｌｏｇ或）均与配体的碱性强度（ｐＫ＿２）之间存在直线自由能关系，并求出了相应的线性方程式。

The stability constants of binary coordination Compounds ML and ML_2, M=Co￣(2+),Cd￣(2+), L=gly￣-, ala￣-,val￣-,leu￣-,phe￣-,try￣-,have been determined at 37℃with ionicstrength μ= 0. 02(NaCl)by potentiometric method,and the protonation constants of corresponding ligands were also determined simultaneously. It was found that the stabllity ofcoordination compounds was correlated with the base strength of ligands.The linear epnadon were obtained.