Solvent Effect on Redox Potentials of Polynuclear Metal Complexes

溶剂对多核金属配合物氧化还原电位的影响

• 批准号: 10440224
• 负责人: ICHIMURA Akio
• 金额: $ 1.28万
• 依托单位: Osaka City University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10440224/
• 关键词: multi-nuclear metal complexes; redox potentials; solvent effect; voltammetry; bifferocene; 1,2-diferrocenylethane; ジフェロセニルエタン; 分光電気化学; 混合原子価状態

The redox behavior of multi-metal complexes exhibits usually the multi-step one-electron transfer processes. The redox potentials are mainly dependent on the degree of interaction among central metal ions and the solvation energy of reductant and oxidant species. In this report, we have studied the solvent effect on the redox potentials for the two one-electron oxidation processes of biferrocene ([Fc-Fc]) and 1,2-differocenylethane ([FcCHィイD22ィエD2]CHィイD22ィエD2Fc]). The electrode reaction entropies were determined from the temperature dependence on the redox potentials for each oxidation step. The ratio of entropy ΔSィイD10ィエD1ィイD22ィエD2/ΔSィイD10ィエD1ィイD21ィエD2 for the biferrocene redox system, where ΔSィイD10ィエD1ィイD21ィエD2 and ΔSィイD10ィエD1ィイD22ィエD2 are the electrode reaction entropies for the first one-electron oxidation of [Fc-Fc]ィイD1+ィエD1/([Fc-Fc]) and the second one-electron oxidation of [Fc-Fc]ィイD12+ィエD1/([Fc-Fc]ィイD1+ィエD1), respectively, is nearly 2, whereas that for the 1,2-differrocenylethane system is nearly 1. Furthermore, ΔSィイD10ィエD1ィイD21ィエD2([Fc-Fc]ィイD1+ィエD1/([Fc-Fc]) is smaller than, ΔSィイD10ィエD1ィイD21ィエD2([FcCHィイD22ィエD2CHィイD22ィエD2Fc]ィイD1+ィエD1/([([FcCHィイD22ィエD2CHィイD22ィエD2Fc]) . These results suggest that the solvation for [Fc-Fc]+ and [Fc-Fc]2+ is represented as charge delocalized ([Fc-Fc]ィイD1+ィエD1)(S)ィイD2pィエD2 and ([Fc-Fc]ィイD12+ィエD1)(S)ィイD2qィエD2 , respectively, where S represents a solvent molecule, and that the solvation for [FcCHィイD22ィエD2CHィイD22ィエD2Fc]ィイD1+ィエD1 and [FcCHィイD22ィエD2CHィイD22ィエD2Fc]ィイD12+ィエD1 is represented as charge localized (S)ィイD2τィエD2ィイD1+ィエD1[FcCHィイD22ィエD2CHィイD22ィエD2Fc]ィイD1+ィエD1 and (S)ィイD2τィエD2ィイD1+ィエD1[FcCHィイD22ィエD2CHィイD22ィエD2Fc]ィイD1+ィエD1(S)ィイD2τィエD2, respectively.

多金属配合物的氧化还原行为通常表现为多步单电子转移过程。氧化还原电位主要取决于中心金属离子之间的相互作用程度以及还原剂和氧化剂物种的溶剂化能。本文研究了溶剂效应对双二茂铁（[Fc-Fc]）和1，2-二苯乙烯乙烷（[FcCH <$D22 <$D2]CH <$D22 <$D2Fc]）两个单电子氧化过程的氧化还原电位的影响。电极反应熵由每个氧化步骤的氧化还原电位的温度依赖性确定。双二茂铁氧化还原体系的熵比ΔS_（10）D_（10）D_（11）D_（22）D_（22）D_（22）/ΔS_（10）D_（11）D_（21）D_（21）D_（22），其中，ΔS β D10 β D1 β D21 β D2和ΔS β D10 β D1 β D22 β D2是[Fc-Fc] β D1+ β D1/（[Fc-Fc]）的第一次单电子氧化和[Fc-Fc] β D1+ β D1/（[Fc-Fc]）的第二次单电子氧化的电极反应熵。イD1, 2 +此外，ΔS β D10 β D1 β D21 β D2（[Fc-Fc] β D1+ β D1/（[Fc-Fc]）小于ΔS β D10 β D1 β D21 β D2（[FcCH β D22 β D2CH β D22 β D2Fc] β D1+ β D1/（[（[FcCH β D22 β D2CH β D22 β D2Fc]）。这些结果表明，[Fc-Fc]+和[Fc-Fc]2+的溶剂化表示为电荷离域（[Fc-Fc] Fc D1+ Fc D1）（S）Fc D2 p Fc D2和（[Fc-Fc] Fc D12+ Fc D1）（S）Fc D2 q + Fc D2，其中S表示溶剂分子，并且[FcCH <$N D22 <$N D2CH <$N D22 <$N D2 Fc]<$N D1+<$N D1和[FcCH <$N D22 <$N D2CH <$N D2 Fc]<$N D12+<$N D1的溶剂化表示为电荷局部化的（S）<$N D2 <$N D1+<$N D1[FcCH <$N D22 <$N D2CH <$N D22 <$N D2 Fc]分别为FcCH D1 + FcCH D2和（S）FcCH D2 + FcCH D2 [FcCH D2] FcCH D2 [FcCH D2

项目成果

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