权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

The Structure-Reactivity Relationship in Heme Complexes. An Important Role of Rotational Orientations of Axial Ligands

血红素复合物的结构-反应性关系。

基本信息

批准号：
03671034
负责人：
SATO Mitsuo
金额：
$ 1.34万
依托单位：
Teikyo University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03671034/
关键词：
Low-spin Fe(III) heme complexes Direction of low- symmetry field Principal axes of g tensor Principal axes of hyperfine tensor ESR of low-spin Fe(III) complexes Rotational orientation of axial ligands Direction of maximum unpaired spin density

项目摘要

Electron spin resonance (ESR) data for low-spin Fe(III) heme complexes are analyzed within the framework of low-symmetry (C_2) crystal field model. In the analysis, the effect of the rotational orientation angle (phi_*) of axial ligands is taken into consideration. Equations are derived which relate phi_* with the orientation angle of the rhombic field and those of the principal axes of g and hf tensors. The direction of the maximum unpaired spin density, derived from the wave functions of the Kramers doublets, is found approximately parallel to the direction of the low-symmetry field.With these angular relations, ESR data previously reported for myoglobin azide (MbN_3) and those recently observed for model heme complexes, such as Fe(TPP)(OMe)_2^- and Fe(TPP)(OMe)(CN), are reevaluated and analyzed, respectively. It is found that the direction of the maximun unpaired spin density in MbN_3 is different from that reported previously. In model complexes, the angular analysis has enabled us to determine the relative orientations of g and hf tensors, the sign of g tensor determinant, and the low-symmetry crystal field parameters. The structure-reactivity relationship in heme complexes is discussed in the light of the angular relations and emphasis is placed to an important role of the axial ligand orientation.

在低对称性（C_2）晶场模型的框架下，分析了低自旋Fe（III）血红素配合物的电子自旋共振（ESR）数据。分析中考虑了轴向配体的旋转取向角φ * 的影响。导出了φ * 与菱形场取向角以及g张量和hf张量主轴取向角的关系式。根据Kramers双峰波函数得到的最大未成对自旋密度的方向与低对称场的方向近似平行，利用这些角度关系，分别对以前报道的肌红蛋白叠氮化物（MbN_3）的ESR数据和最近观察到的模型血红素复合物Fe（TPP）（OMe）_2^-和Fe（TPP）（OMe）（CN）的ESR数据进行了重新评价和分析。发现MbN_3中最大未成对自旋密度的方向与以前报道的不同。在模型复合物中，角分析使我们能够确定g张量和hf张量的相对取向，g张量行列式的符号，以及低对称性晶场参数。从角的角度讨论了血红素配合物的结构-反应性关系，并强调了轴向配体取向的重要作用。