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Dynamic Structure and Novel Functions of Dicobalt Complexes

二钴配合物的动态结构和新功能

基本信息

批准号：
16350076
负责人：
HISAEDA Yoshio
金额：
$ 10.11万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

We constructed redox switchable molecular containers with dicobalt complexes. Molecuar switches are the attractive components of molecular electronic devices capable of inducing chemical and physical changes in response to external stimuli such as electrical current, light, and heat. In this study, switching systems were established by using the structural change of dicobalt complexes. Cobalt complexes prefer a six-coordinated structure at the Co(III) state while the Co(II) species prefer a four-coordinated structure. Reversible redox change of dicobalt complexes between Co(III) and Co(II) provides a stable molecular switching system. When diamine was used as axial ligand, each amino groups of diamine were coordinated to cobalt (III) center of planar dicobalt complex with bridged structure. Dissociation of diamines were accompanied by the reduction of dicobalt (III, III) centers to Co(II, II) form by electrochemical stimulus. The bridged structure was recovered with oxidation of cobalt … More centers. We constructed a switching system using this strategy as a molecular container containing a crown ether moiety in diamino-molecules.One-pot syntheses of new water-soluble dicobalt complexes having two cobalt-carbon bonds were investigated. The complexes were characterized by 'H NMR and UV-vis spectroscopies as well as ESI-MS. These complexes were photo-sensitive and the photo-cleavage of the cobaltcarbon bonds upon irradiation with visible light produced methyl radicals which were detected by ESR spin-trapping techniques. The dicobalt complexes exhibited a high ability for DNA cleavage in comparison to that for the corresponding monocobalt complex.A novel dicobalt complex, where a dinucleating ligand has two N2O2 metal-binding sites which are linked to each other with a phenyl spacer, was synthesized and its redox behavior was investigated in THF using cyclic voltammetry in comparison with that for the corresponding mononuclear complex. The controlled-potential electrolysis of alkyl halides at-1.60 V vs. Ag/AgCl in the presence of the rigid and planar dicobalt complex led to reductive coupling. The use of rigid, planar dicobalt complex to effect the reductive dimerization of alkyl halides has been demonstrated for the first time. Less

我们构建了具有二钴配合物的氧化还原可切换分子容器。分子开关是分子电子器件中极具吸引力的元件，它能够对电流、光和热等外部刺激产生化学和物理变化。在本研究中，利用二钴配合物的结构变化建立了开关系统。钴配合物在Co（III）态倾向于六配位结构，而Co（II）态倾向于四配位结构。二钴配合物在Co（III）和Co（II）之间的可逆氧化还原变化提供了一个稳定的分子开关系统。当二胺作为轴向配体时，二胺的每个氨基被配位到具有桥式结构的平面二钴配合物的钴（III）中心。二胺解离反应伴随着电化学刺激下二钴（III， III）中心还原为Co（II， II）形式。通过氧化钴恢复了桥接结构。我们利用这一策略构建了一个开关系统，作为在二氨基分子中含有冠醚片段的分子容器。研究了一锅法合成具有两个钴碳键的新型水溶性二钴配合物。通过核磁共振、紫外-可见光谱和ESI-MS对配合物进行了表征。这些配合物是光敏的，在可见光照射下，钴碳键的光裂解产生甲基自由基，并通过ESR自旋捕获技术检测到甲基自由基。与相应的单钴配合物相比，二钴配合物表现出更高的DNA切割能力。合成了一种新型的二钴配合物，其中双核配体具有两个N2O2金属结合位点，并通过苯基间隔剂相互连接，并用循环伏安法研究了其在THF中的氧化还原行为，并与相应的单核配合物进行了比较。在刚性和平面的二钴配合物存在下，烷基卤化物在1.60 V下对Ag/AgCl的控制电位电解导致了还原偶联。首次证实了刚性平面二钴配合物对烷基卤化物还原二聚化反应的影响。少