Metal Complexes with Macrocyclic Ligands. Part XXXVIII. Steric effects in the copper(II) and nickel(II) complexes with tetra-N-alkylated 1,4,8,11-tetraazacyclotetradecanes
作者:Martin R. Oberholzer、Markus Neuburger、Margareta Zehnder、Thomas A. Kaden
DOI:10.1002/hlca.19950780220
日期:1995.3.22
A series of tetra-N-alkylated 1,4,8,11-tetraazacyclotetradecanes have been synthesized and their complexation potential towards Ni2+ and Cu2+ studied. In the case of sterically demanding alkyl substituents, such as i-Pr, PhCH2, or 2-MeC6H4CH2, no metal complexes are formed, whereas for substituents such as Me, Et, and Pr, the metal ion is incorporated into the macrocycle. The spectroscopic properties
已经合成了一系列的四-N-烷基化的1,4,8,11-四氮杂环十四烷,并且研究了它们对Ni 2+和Cu 2+的络合潜力。在空间上需要烷基取代基(例如i-Pr,PhCH 2或2-MeC 6 H 4 CH 2)的情况下,不会形成金属络合物,而对于诸如Me,Et和Pr的取代基,金属离子为纳入大循环。水溶液中Ni 2+和Cu 2+配合物的光谱性质表明,取决于N的空间位阻-取代基,配合物是正方形平面的或五配位的。所有这些Ni 2+和Cu 2+络合物均与N反应生成三元物质,其稳定性已通过分光光度滴定法确定。N的结合趋势随着烷基取代基的空间位阻的增加而降低。X射线研究带有两个Me和两个Pr基团取代的具有大环11的Ni 2+配合物以及带有四乙基衍生物8的Cu 2+配合物的X射线研究表明,在固态下,金属离子呈正方形平面配合,对四面体几何形状的变形很小。