四氮杂18-冠-6及其臂式衍生物与稀土离子螯合的边臂效应  

Side Arms' Chelating Effect of Tetraaza-18-Crown-6 and Its Armed-Derivatives on Rare Earth Ions

作　　者：张强[1] 刘世昌[1] 高生华[1] 

机构地区：[1]内蒙古师范大学化学与环境科学学院,内蒙古呼和浩特010022

出　　处：《中国稀土学报》2007年第2期143-149,共7页Journal of the Chinese Society of Rare Earths

基　　金：内蒙古自然科学基金资助项目(200508010212;200607010207)

摘　　要：合成和表征了1,10-二氧-4,7,13,16-四氮杂18-冠-6(L1)母体及其两种乙酸乙酯臂式衍生物(L2,L3)。采用pH电位滴定法测定了水溶液中三种冠醚配体与Ce3+,Nd3+,Sm3+,Eu3+,Gd3+,Tb3+,Dy3+和Er3+硝酸盐络合的稳定常数。设计编制了一种新的多元配合物稳定常数计算程序(QB-TITFIT2005),并对实验数据进行拟合处理。用循环伏安法考察了水溶液中Eu3+和Sm3+及其冠醚配合物的电极反应行为。结果表明:稀土离子与3种冠醚均可形成1∶1的配合物。冠醚边臂的螯合效应显著地增加其配合物的稳定性,参与螯合的边臂数受离子大小的限制,四臂冠醚(L3)与半径较大的稀土离子有较大的螯合稳定性,而半径较小的稀土离子与三臂冠醚(L2)的螯合稳定性较高。循环伏安测定数据也支持了这一结果。The parent aracrown ether 1, 10-dioxa-4, 7, 13, 16-tetraaza-18-erown-6（L1） and its two acetic ether armed-derivatives （L2 and L3） were synthesized and characterized. The protonation constants of the maeroeyeles and the stability constants of their complex formation with Ce^3＋, Nd^3＋ , Sm^3＋ , Eu^3＋ , Gd^3＋ , Tb^3＋, Dy^3＋ and Er^3＋ were determined in aqueous solution by potentiometry. A new computer program, QB-TITFIT2005, was developed in which multieomponent complex stability constants were determined by potentiometry. The data were processed by using the program. The electrode reactive behaviors of Eu^3＋, Sm^3＋ and their crown ether complexes were investigat-ed in aqueous solution by cyclic voltammetry. The resuits indicated that three kinds of crown ethers can form stable 1 ： 1 stoichiometric complexes with rare earth ions. The stability of complexes was remarkably enhanced by the chelation between the arms of azacrown ethers and metal ions. The number of the side arm participation in the chelation has restricted by the size of ion. There was an excellent chelating stability between the tetraarmed-crown ether（L3） and the rare earth ions with large radius, and between the triarmed-crown ether（L2） and the rare earth ions with small radius. The cyclic voltammetric measurements gave strong support to the results.

关 键 词：臂式氮杂冠醚 稀土配合物 电位滴定 循环伏安法 边臂效应 

分 类 号：O614.33[理学—无机化学] O627.22[理学—化学]