INTRAMOLECULAR 2-ELECTRON TRANSFER BETWEEN MANGANESE(II) AND SEMIQUINONE LIGANDS - SYNTHESIS AND CHARACTERIZATION OF MANGANESE 3,5-DI-TERT-BUTYLQUINONE COMPLEXES AND THEIR RELATIONSHIP TO THE PHOTOSYNTHETIC WATER OXIDATION SYSTEM
INTRAMOLECULAR 2-ELECTRON TRANSFER BETWEEN MANGANESE(II) AND SEMIQUINONE LIGANDS - SYNTHESIS AND CHARACTERIZATION OF MANGANESE 3,5-DI-TERT-BUTYLQUINONE COMPLEXES AND THEIR RELATIONSHIP TO THE PHOTOSYNTHETIC WATER OXIDATION SYSTEM
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DOI：
10.1021/ja00319a023
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发表时间：
1984-01-01
影响因子：
15
通讯作者：
PIERPONT, CG
中科院分区：
文献类型：
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作者：
LYNCH, MW;HENDRICKSON, DN;PIERPONT, CG
报道了制备绿色 Mn4(3,5-DBSQ)8 [锰 3,5-二叔丁基醌]四聚体的合成程序。该配合物的光谱和结构表征表明，金属离子为 Mn(II) 形式，并且醌配体以半醌形式键合。高自旋d5金属离子和顺磁性配体之间的弱磁交换导致室温下每个Mn(3,5-DBSQ)2单元5.1μB的磁矩。结构研究表明，该分子的金属离子是 Mn(IV)，醌配体以儿茶酚盐形式键合。 EPR 光谱验证了金属离子的 d3 构型。在室温下的甲苯溶液中，配合物的紫色晶体产生绿色溶液。温度低于 230°C 时K 溶液呈现晶体的紫色。光谱证据表明，在甲苯中 230 至 300 K 的温度范围内，配合物的 MnII(3,4-DBSQ)2(py)2（绿色）和 MnIV(3,4-DBCat)2(py)2（紫色）形式之间达到平衡。在吡啶中，平衡温度范围增加了大约 100°C。 K. 将锰络合物的物理和结构特性与与光合水氧化相关的锰蛋白的特性进行比较。
Synthetic procedures for preparing the green Mn4(3,5-DBSQ)8 [manganese 3,5-di-tert-butylquinone] tetramer are reported. Spectral and structural characterization of the complex shows that the metal ions are in the Mn(II) form and that the quinone ligands are bonded as semiquinones. Weak magnetic exchange between the high-spin d5 metal ions and the paramagnetic ligands results in a magnetic moment of 5.1 .mu.B per Mn(3,5-DBSQ)2 unit at room temperature. A structural study has shown that the metal ion of this molecule is Mn(IV) and that the quinone ligands are bonded in their catecholate form. EPR spectra verify the d3 configuration of the metal ion. In toluene solution at room temperature purple crystals of the complex give a green solution. At temperatures below 230.degree. K the solution assumes the purple color of the crystals. Spectral evidence suggests an equilibrium between MnII(3,4-DBSQ)2(py)2 (green) and MnIV(3,4-DBCat)2(py)2 (purple) forms of the complex over the temperature range between 230 and 300 K in toluene. In pyridine the equilibrium temperature range is increased by approximately 100.degree. K. The physical and structural properties of the manganese complexes are compared with the properties of the manganese protein associated with photosynthetic water oxidation.