Solvent Effect on Redox Potentials of Polynuclear Metal Complexes

多金属复合体的redox行为通常展示了多步骤一电子传输过程。Redox潜力主要取决于中央金属和氧化物物种中的相互作用程度和溶解能量的程度。在这份报告中，我们研究了双离子氧化过程中的redox潜力对双离子（[Fc-Fc]）和1，2-differocenylethane（[FcCH-D22-D2]CH-D22-D2 Fc]）的溶解效应。电致反应的入口是由温度依赖于每一个氧化步骤的redox潜力决定的。The ratio of entropy ΔS D10 D1 D22 D2/ΔS D10 D1 D21 D2 for the biferrocene redox system，where ΔS-D10-D1-D21-D2 and ΔS-D10-D1-D22-D2 are the electrode reaction entropies for the first one-electron oxidation of [Fc-Fc]]イD1+イエD1/（[Fc-Fc]） and the second one-electron oxidation of [Fc-Fc] D12+ D1/（[Fc-Fc] D1+ D1）， respectively， is nearly 2， whereas that for the 1，2-differrocenylethane system is nearly 1。Furthermore，[Fc-Fc][Fc-Fc][Fc-Fc][Fc-Fc]] is smaller than，[Fc-Fc]] D10 [D1] D21 [FcCH [D22][FcCH [D22][FcCH [D22][D22][FcCH [D22][D22][FcCH [D2CH]。这些结果建议对[Fc-Fc]+和[Fc-Fc]2+的解决方案表示为单独收费（[Fc-Fc]イイD1+イエD1）（S）イイD2pイエD2 and（[Fc-Fc]イイD12+イエD1）（S）イイD2qイエD2 ， respectively， where S represents a solvent molecule，and that the solvation for [FcCH_D22_イイD1+イエD1 and （S）イイD2イイD1+イエD1[FcCHイD22イエD2CHイD22イエD2Fc]イD1+イエD1（S）イD2イエD2， respectively。

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.