SYNTHESIS AND ELECTROCHEMICAL PROPERTIES OF OXO-BRIDGED MANGANESE DIMERS INCORPORATING ALKALI AND ALKALINE-EARTH CATIONS
SYNTHESIS AND ELECTROCHEMICAL PROPERTIES OF OXO-BRIDGED MANGANESE DIMERS INCORPORATING ALKALI AND ALKALINE-EARTH CATIONS
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DOI：
10.1016/0020-1693(94)04047-8
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发表时间：
1994-10-01
影响因子：
2.8
通讯作者：
CIRINGH, Y
中科院分区：
文献类型：
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作者：
HORWITZ, CP;CIRINGH, Y
二聚体[(1)Mn-III](2)(Mu-O)(3)是通过单核Mn(II)络合物在CH3CN中氧化合成的。所用配体为3，3‘-17-冠-6-SAL-3-CH3-OPHEN(1)。二聚体3在DMF中与KPF6和BA(SO3CF3)(2)反应生成3 2KPF(6)和3 2BA(SO3CF3)(2)，用光谱和电化学方法对它们进行了分离和表征。所有的二聚体都参与了一个可逆的双电子转移过程，该过程产生了相应的Mn-II，Mn-II(Mu-oxo)二聚体。在二聚体的冠醚部分加入阳离子使3的形式还原电势向更正值移动：E度(3)=-120 mV，CH2Cl2；E度(3 2KPF(6))=0 mV，CH3CN；E度(3 2BA(SO3CF3)(2))=180 mV，CH3CN ALVS SSCE。UV-Vis实验结果表明，形式还原电势的移动主要是由静电效应引起的，而不是由于d轨道在Mn(III)中心上的扰动。
The dimer [(1)Mn-III](2)(mu-O) (3) was synthesized by oxygenation of the mononuclear Mn(II) complex in CH3CN. The ligand used was 3,3'-17-crown-6-SAL-3-CH3-OPHEN (1). Dimer 3 reacted with KPF6 and Ba(SO3CF3)(2) in DMF forming 3 2KPF(6) and 3 2Ba(SO3CF3)(2) and these were isolated and characterized by spectroscopic and electrochemical means. All of the dimers participated in a reversible two-electron transfer process that produced the corresponding Mn-II,Mn-II (mu-oxo) dimer. Inclusion of cations into the crown ether portions of the dimer caused that formal reduction potential of 3 to shift to more positive values: E degrees (3) = - 120 mV, CH2Cl2; E degrees (3 2KPF(6)) = 0 mV, CH3CN; E degrees (3 2Ba(SO3CF3)(2)) = 180 mV, CH3CN all versus SSCE. Results of UV-Vis experiments suggested that the shift in formal reduction potential was caused primarily by an electrostatic effect and not a perturbation of the d orbitals on the Mn(III) centers.