Pyrrolinium-Substituted Persistent Zwitterionic Ferrocenate Derivative Enabling the Application of Ferrocene Anolyte

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 derivatives clearly explain origin of their thermal stability orbital interactions between iron cyclopentadienyl ligand. Exploiting facile Fe(II/I) redox chemistry, successfully demonstrated that pyrrolinium-substituted ferrocene derivative can be applied as an example derivatized anolyte for redox-flow batteries. These will not only deepen our understanding intrinsic chemistry but have potential to open way rational design metallocenate various applications.