Preferred orientation of imidazole ligands in metalloporphyrins
Preferred orientation of imidazole ligands in metalloporphyrins
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DOI：
10.1021/ja00266a008
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发表时间：
1986-03
影响因子：
15
通讯作者：
W. Scheidt;D. Chipman
中科院分区：
文献类型：
--
作者：
W. Scheidt;D. Chipman
最近的工作表明，轴向配体方向可以影响金属卟啉的理化性质。晶体学数据分析表明，金属卟啉中的轴向咪唑配体倾向于偏好空间上不利的取向，从而使赤道 M-N/sub p/ 键黯然失色。对广泛选择的代表性系统的电子效应的电荷迭代扩展休克尔理论计算表明，M-N（咪唑）..pi.. 键中存在先前未被认识的取向偏好，该键有利于重叠取向。有点令人惊讶的是，发现该..pi..键主要由金属p..pi..-咪唑p..pi..相互作用支配。这些理论结果解释了为什么取向效应似乎对金属 d/sup n/ 构型、自旋态、氧化态以及第六轴向配体的存在或不存在不敏感。 23 篇参考文献、1 张图、3 个表格。
Recent work has suggested that axial ligand orientation can affect the physiocochemical properties of metalloporphyrins. Analysis of crystallographic data indicates that axial imidazole ligands in metalloporphyrins tend to prefer sterically unfavorable orientations that eclipse equatorial M-N/sub p/ bonds. Charge iterative extended Hueckel theory calculations on electronic effects for a broad selection of representative systems indicate a previously unrecognized orientational preference in the M-N(imidazole) ..pi.. bond which favors eclipsed orientations. Somewhat surprisingly, this ..pi.. bond is found to be dominated by the metal p..pi..-imidazole p..pi.. interaction. These theoretical results provide an explanation of the mystery of why the orientation effect seems to be insensitive to metal d/sup n/ configuration, spin state, oxidation state, and the presence or absence of a sixth axial ligand. 23 references, 1 figure, 3 tables.