Design of Organic-Oraganometallic Hybrid Molecules with Mixed-valence Redox Activity

近年来，由于新型π偶联材料的制备及其在材料科学中的应用，含有多个氧化还原中心的分子的研究在材料科学领域引起了极大的研究兴趣。此外，这种具有两个以上氧化还原活性金属中心的分子是研究由这些多金属体系衍生的混合价态进行多电子转移过程的一个有吸引力的目标。另一方面，利用含16族元素的5π和7π电子骨架设计具有氧化还原活性的新型有机中心的兴趣使我们探索合成新的含硫5元杂环(S)。因此，我们设计了由噻吩桥联的低聚二茂铁衍生物作为阴极和阳极多重氧化还原活性的有机-金属有机杂化分子。每个分子都是以二茂铁或二茂铁基氯化锌为原料，通过与噻吩衍生物或低聚硫吩衍生物的交叉偶联反应，系统地和选择性地合成的。通过物理和光谱手段对分子进行了表征。新型有机-金属有机杂化分子的循环伏安曲线显示，由异常稳定的5π噻吩基阳离子，7π噻吩基阴离子衍生的可逆阳极和阴极台阶清晰可见。此外，这些分子表现出多个不同的可逆阳极步骤，这些步骤来自二茂铁阳离子，这些阳离子被噻吩基或低聚硫吩基隔开。

In recent years, the study of molecules comprising multiple reduction-oxidation (redox) centers have attracted considerable research interest in the field of material science due to the preparation of new π-conjugated materials with application in material science. Moreover, this kind of molecule having more than two redox-active metal centers is a fundamentally attractive target for the study of multi-electron transfer processes via the mixed valence state derived from these multi-metallic systems. On the other hand, interest in the design of novel redox-active organic centers by the use of a 5π- and 7π- electron framework containing group 16 elements has led us to explore the synthesis of new 5-membered heterocycles containing sulfur atom (s). Therefore, we have designed oligo-ferrocene derivatives bridged by thiophene, bithiopehene, and terthiophene as both cathodic and anodic multiple-redox active organic-organometallic hybrid molecules. Each molecule has been systematically and selectively synthesized from heloferrocene or ferrocenylzinc chloride by cross-coupling reactions with thiophene or oligothiophene derivatives. Characterization of the molecules was performed by physical and spectroscopic means. The cyclic voltammograms of the novel organic-organometallic hybrid molecules containing both thiophene and ferrcene fragments showed well-defined reversible both anodic and cathodic steps derived from the unusually stable 5π thiophene radical cations, 7π thiophene radical anions. In addition, the molecules showed multiple distinct reversible anodic steps derived from ferrocenium cations separated from each other by a thiophene or an oligothiophene.