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Stereoselective Formation and Chemical Properties of Chiral Polynuclear Complexes Depending on Oxidation Numbers

取决于氧化数的手性多核配合物的立体选择性形成和化学性质

基本信息

批准号：
14540510
负责人：
OKAMOTO Ken-ichi
金额：
$ 2.24万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14540510/
关键词：
S-Bridged Complexes Electric Redox Behavior Spectroelectrochemistry Spectrochemistry Stereochemistry

项目摘要

The UV-vis spectroelectrochemical properties of S-bridged tricobalt(III) complexes [Co^<III>{Co^<III>(aet or L-cys)_3}_2]^<3+ or 3-> and dicobalt(III) complexes [Co^<III>{Co^<III>(aet or L-cys)_3}(dien)]^<3+ or 0> (aet = 2-aminoethanethiolate, L-cys = L-cysteinate, dien = diethylenetriamine) were investigated using a thin-layer quartz cell with a platinum mesh working electrode. The absorption spectroelectrochemical measurements for the tricobalt(III) complexes indicated that a two-electron reduction proceeds through pseudo two-steps, Co^<III>Co^<III>Co^<III>→Co^<III>Co^<II>Co^<III>→Co^<III>Co^<II>Co^<II> for the aet complex, while through pseudo one-step for the L-cys complex. The CD spectroelectrochemical measurements demonstrated that the optically active isomer (ΔΔ form) of the aet tricobalt(III) complex loses chirality during the one-electron reduction, whereas the Δ_<LLL>Δ_<LLL> isomer of the L-cys tricobalt(III) complex is reduced with an inversion of configuration, to form the Λ_<LLL>Λ_<LLL> isomer. The Λ_<LLL>Λ_<LLL> isomer is reduced with a retention of configuration. The aet and L-cys dicobalt(III) complexes were converted to the corresponding tricobalt(III) complexes by electrochemical reduction, accompanied by the release of the Co(II) ion and dien ligand. It was also elucidated that this conversion occurred with a retention of configuration.Similar properties and reactivities have been studied for the polynuclear complexes with various metal ions and organic ligands.

采用铂网工作电极，在石英薄层池中研究了S-桥联三钴（III）配合物[Co^<III>{Co^<III>（aet或L-cys）_3}_2]^<3+或3->和二钴（III）配合物[Co^<III>{Co^<III>（aet或L-cys）_3}（dien）]^<3+或0>（aet = 2-氨基乙硫醇，L-cys = L-半胱氨酸，dien =二乙烯三胺）的紫外-可见光谱电化学性质。三钴配合物的吸收光谱电化学研究表明，aet配合物的双电子还原过程为准两步：Co^<III>Co^<III>Co^<III>→Co^<III>Co^<II>Co^<III>→Co <III>^<II>Co^<II>，而L-cys配合物的双电子还原过程为准一步。CD光谱电化学研究表明，aet三钴（III）配合物的光学活性异构体（ΔΔ形式）在单电子还原过程中失去手性，而<LLL><LLL>L-cys三钴（III）配合物的Δ_ Δ_异构体在单电子还原过程中发生构型反转，形成Λ_<LLL>Λ_<LLL>异构体。Λ_<LLL>Λ_<LLL>异构体被还原，构型保持不变。aet和L-cys二钴（III）配合物通过电化学还原转化为相应的三钴（III）配合物，伴随着Co（II）离子和二烯配体的释放。研究了不同金属离子和有机配体的多核配合物的类似性质和反应性。