Synthesis, characterization, and spectroscopic properties of three novel pentadentate copper(II) complexes related to the metal-chelating inhibitors against DNA binding with HIV-EP1
作者:Hiromasa Kurosaki、Rakesh Kumar Sharma、Sachiko Aoki、Teruhiko Inoue、Yoshinari Okamoto、Yukio Sugiura、Mitsunobu Doi、Toshimasa Ishida、Masami Otsuka、Masafumi Goto
DOI:10.1039/b006949n
日期:——
Three potentially five-coordinate peptide ligands having a pyridine and two histidine moieties, were synthesized to study their copper(II) complexation. Blue copper(II) complexes with deprotonated amide groups were isolated from methanolic solutions of the corresponding ligands with equimolar Cu(OAc)2·H2O. The structures of two of them were determined by X-ray crystallography. The Cu is coordinated to five nitrogen atoms in both complexes; the coordination geometry was a distorted square pyramid in one, and intermediate between a square pyramid and trigonal bipyramid in the other. EPR spectra in frozen methanol solutions at 77 K as well as visible absorption spectra indicate that the distortion of the geometry around the copper is reduced by the introduction of an alkylamine substituent on the pyridine of the ligand and that the substituted complexes distort toward trigonal bipyramidal geometry compared to the unsubstituted one in solution.
合成了三种可能具有五配位特征的肽配体,每个配体包含一个吡啶和两个组氨酸部分,旨在研究它们与铜(II)的配位作用。从相应配体与等摩尔Cu(OAc)2·H2O的甲醇溶液中分离得到了含有去质子化酰胺基团的蓝色铜(II)配合物。通过X射线晶体学确定了其中两个配合物的结构。在这两个配合物中,铜均与五个氮原子配位;其中一个的配位几何形状为扭曲的四角锥,另一个则介于四角锥和三角双锥之间。在77K下测得的冷冻甲醇溶液的EPR谱以及可见吸收光谱表明,在配体的吡啶上引入烷基胺取代基可以减少铜周围几何形状的扭曲,并且与未取代的配合物相比,取代后的配合物在溶液中更倾向于形成三角双锥几何形状。