Metallocenium Chemistry and Its Emerging Impact on Synthetic Macromolecular Chemistry

Cationic metallocenes (or metalloceniums) are a class of sandwich-type compounds with cationic metal centers, which are usually iron, cobalt, or rhodium. These unique charged complexes have received wide attention owing to both rich electrochemistry and the positive charge associated with the transition metal. They are potential building blocks for fabricating functional polyelectrolytes and for possible biomedical applications. As the basis of all metallocenium-containing materials, the synthetic chemistry of metallocenium has been a recently emerging field. In this account, we give a brief summary of metallocenium chemistry. Furthermore, its emerging impact on functional macromolecules is also covered. 1 Introduction 2 Cobaltocenium-Containing Derivatives and Macromolecules 2.1 General Synthetic Routes 2.2 Disubstituted Cobaltoceniums 2.3 Carboxycobaltocenium and Its Derivatives 2.4 Ethynylcobaltocenium and Its Derivatives 2.5 Other Cobaltocenium Derivatives 3 Rhodocenium-Containing Derivatives and Macromolecules 4 Summary and Outlook