Development of New Double-Stranded Phenylalanyl Chelators Using .ETA.-.CHI. Diagrams and Binding Constants for Chelators and Lanthanide Ions
作者:Shigeki Kobayashi、Makoto Watanabe、Toshiyuki Chikuma
DOI:10.1248/cpb.58.620
日期:——
We examined the interaction between several ligands and alkaline (M+) or lanthanide (Ln3+) ions using η–χ diagrams. η and χ represent absolute hardness and absolute electronegativity, respectively. Based on the diagrams, new double-stranded amino acid chelators (1) conjugated to Cat (catechol) were synthesized. They had two cavities coordinating hard metal ions, such as Li+ and K+, and soft metal ions, such as Lu3+ and Eu3+. 1 formed a solvated molecular complex, 1–Ln3+, with a molar ratio of 1 : 1 at a binding constant (Kb) of 104—106 with Y3+, La3+, Eu3+, and Lu3+, respectively. With a chemical hard ion, Li+, we found that the Kb of the 1–Eu3+ complex increased. The optimized geometries of 1–Lu3+ and 1–La3+ complexes were obtained from B3LYP correlation functions using Stuttgart-Dresden-Bonn (SDD) Effective Core Potential (ECP) basis sets for Lu3+ and La3+ ions. The double-stranded chelator may prove useful for studying the selective separation of lanthanide ions, and the development of functional peptides.
我们利用η-χ图研究了几种配体与碱性(M+)离子或镧系(Ln3+)离子之间的相互作用。根据这些图表,合成了与 Cat(儿茶酚)共轭的新型双链氨基酸螯合剂(1)。它们有两个空腔,分别配位 Li+ 和 K+ 等硬金属离子以及 Lu3+ 和 Eu3+ 等软金属离子。1 与 Y3+、La3+、Eu3+ 和 Lu3+ 分别形成摩尔比为 1 : 1、结合常数(Kb)为 104-106 的溶解分子配合物 1-Ln3+。在化学硬离子 Li+ 的作用下,我们发现 1-Eu3+ 复合物的 Kb 增加了。我们利用斯图加特-德累斯顿-波恩(SDD)有效核心势能(ECP)基集对 Lu3+ 和 La3+ 离子进行 B3LYP 相关函数计算,得到了 1-Lu3+ 和 1-La3+ 复合物的优化几何结构。这种双链螯合剂可能有助于研究镧系元素离子的选择性分离以及功能肽的开发。