摘要
用ｐＨ电位滴定法测定了金属离子（Ｍ^（２＋）＝Ｃｕ^（２＋），Ｃｏ^（２＋），Ｎｉ^（２＋），Ｚｎ^（２＋），Ｃｄ^（２＋）与核酸碱基（Ｌ＝腺嘌呤，胞嘧啶）形成的二元配合物以及与腺昔－５’－三磷酸（ＡＴＰ）形成的三元混配配合物的稳定常数。三元配合物相对于二元配合物的稳定性用平衡常数表示。结果表明：ΔｌｇＫ_ｍ比咪唑或氨的相应配合物ΔｌｇＫ_ｍ大，这可能与三元混配配合物分子内存在配体间的芳环堆积、氢键作用以及π_Ａ－π_Ｂ协同效应有关。
The stability constants of binary complexes ML￣(2+)(M￣(2+)=Cu￣(2+), Co￣(2+), Ni￣(2+),Zn￣(2+), Cd￣(2+); L=Adenine, Cytosine) and their ternary complexes with ATP (Adenosine 5'-triphosphate) were determined by potentiometric pH titration in aqueous solution (T=25℃,I=0.1mol/L NaClO4), the stability of ternary complexes in relation to the stability of their binary parent complexes was characterized by the equilibrium constants △lgK_M (△lgKM=lgK-lgK) corresponding to the equilibrium M (ATP)￣(2-)+ML￣(2+)=M (ATP)L￣(2-)+M￣(2+). The results obtained show that the △lgK_M for L=Adenine and cytosine is larger than that of the corresponding complexes of imidazole or ammonia due to the intramolecular ligand-ligand stacking interaction and hydrogen bond of the ternary complexes.
出处
《高等学校化学学报》
CSCD
北大核心
1995年第10期1500-1503,共4页
Chemical Journal of Chinese Universities
基金
国家教委博士点基金
国家自然科学基金
南京大学配位化学国家重点实验室资助
关键词
配合物
核酸碱基
稳定常数
腺嘌呤
胞嘧啶
Ternary mixed-ligand complexes
ATP
Nucleic acid bases
Stability constants
Stacking interaction
