Metal Complexes of Pentadentate Macrocyclic Ligands Containing Oxygen and Nitrogen as Donor Atoms
作者:M. F�tima Cabral、Rita Delgado
DOI:10.1002/hlca.19940770212
日期:1994.3.23
sequence of protonation of ligand 1 was studied by 1H-NMR spectroscopy. The Irving-Williams' order of stability is obeyed for the complexes of all the ligands, and the metal complexes of 1 present the higher values of stability. A drop in the stability of all the metal complexes studied is observed when the metal complexes of 1 are compared with the corresponding complexes of 2. The effect of the increase
已合成了四个大环配体:1-oxa-4,7,10,13-四氮杂十五烷(1),1,4-dioxa-7,10,13-三氮杂十五烷(2),1,4- dioxa -7,11 ,14-triazacyclohexadecane(3),1,4-二氧杂-7,11,15- triazacycloheptadecane(4),它们中的一个3,为第一次。在25°C水溶液中,通过电位法测定了配体的质子化常数和由四个配体与一些二价第一系列过渡金属离子Cd 2+和Pb 2+形成的配合物的稳定性常数。和余= 0.10M(KNO 3)。配体1的质子化顺序通过1 H-NMR光谱研究。的欧文-威廉姆斯稳定性的'顺序遵守所有配体的配合物,以及金属配合物1本稳定的更高的值。当将1的金属配合物与2的对应配合物进行比较时,观察到所有研究的金属配合物的稳定性均下降。对于一系列配体2 4的金属配合物,可以观察到大环环尺寸增加的影响,尽管配体的整体碱度略有增加(2的配比为20