N—乙酸取代的四氮杂环十四烷加质子平衡的研究

本文用电位—PH 法测得了5,5,7,12,12,14—六甲基一四氮杂环十叫烷 L~1及其 N-乙酸取代物 L~2和 L~3的加质子常数。发现在大环氮原子α位引入烷基或在氮上引入乙羧基会使配体碱性增强。在水溶液中它们主要似 H_2L 的形式存在。探讨了它们与金属 N~(2+)的配合速率结果表明它们的配合速率有如下关系:L~1》L~2>L~3.

The Study on an Aqueous Solution Eqquilicrium of N-substituted Tetraazacyclotradecane Acetic Acid

The protonation constants of 5,5,7,12,12,14—hexamethyltetraaza-cyclote- tradecane(L~1)and N—siubsttuted derivations L~2,L~3 were determined by potentiometric titration.It is found that the basicity of these ligands is increased when methyl was introduced to the alpha-carbon of the N—atom or acetic acid to N—atomin L~1.In aqueous solutions of the macrocycles, the main species present is theudiprotonation form H2L.the kinetcs of complex formation between L~1,L~2,L~3and Ni(Ⅰ)have been studied.The complexation rate was obtained as follows:L~1>>L~2>L~3.