Here, we report the imidazolium-/pyrrolinium-substituted persistent zwitterionic ferrocenate derivatives, which were characterized by electron paramagnetic resonance (EPR) and ⁵⁷Fe Mössbauer spectroscopy. Additional theoretical studies on these zwitterionic ferrocenate derivatives clearly explain the origin of their thermal stability and the orbital interactions between iron and imidazolium-/pyrrolinium-substituted zwitterionic cyclopentadienyl ligand. Exploiting the facile Fe(II/I) redox chemistry, we successfully demonstrated that the pyrrolinium-substituted ferrocene derivative can be applied as an example of derivatized ferrocene anolyte for redox-flow batteries. These zwitterionic ferrocenate derivatives will not only deepen our understanding of the intrinsic chemistry of ferrocenate but have the potential to open the way for the rational design of metallocenate derivatives for various applications.

中文翻译：

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吡咯啉取代的持久性两性离子二茂铁衍生物使二茂铁阳极液的应用成为可能

在这里，我们报告了咪唑鎓/吡咯啉取代的持久性两性离子二茂铁衍生物，其特征在于电子顺磁共振 (EPR) 和⁵⁷Fe Mössbauer 光谱。关于这些两性离子二茂铁衍生物的其他理论研究清楚地解释了它们热稳定性的起源以及铁和咪唑鎓/吡咯啉取代的两性离子环戊二烯基配体之间的轨道相互作用。利用简便的 Fe(II/I) 氧化还原化学，我们成功地证明了吡咯啉取代的二茂铁衍生物可以用作氧化还原液流电池衍生化二茂铁阳极电解液的一个例子。这些两性离子二茂铁衍生物不仅将加深我们对二茂铁内在化学的理解，而且有可能为合理设计用于各种应用的茂金属衍生物开辟道路。