Metallomacromolecules containing cobalt sandwich complexes: Synthesis and functional materials properties

Abstract

Metallomacromolecules are attracting considerable attention as a class of macromolecular materials with unique properties and applications. Although ferrocene (Fc)-containing macromolecules have occupied the dominant position for several decades in this area and have led to a variety of architectures and applications, the class of cobalt-sandwich-containing macromolecules has recently undergone a booming development. Especially, polymers and dendrimers containing the 18-e cationic cobalticenium (Cc) unit isoelectronic to Fc have been developed during the last few years after overcoming Cc functionalization problems and following the burst of living polymers and dendrimers. Subsequently, remarkable applications have been disclosed including materials physical properties, healthcare and engineering. Meanwhile several other metallopolymers with Co sandwiches containing cyclobutadiene or carborane ligands have also emerged. This review summarizes the most recent progress in the synthesis of metallomacromolecules containing cobalt sandwich complexes and their functional materials properties. Polymerization techniques have included radical polymerization, reversible addition fragmentation chain transfer (RAFT), ring-opening metathesis polymerization (ROMP), condensation polymerization, ring-opening polymerization (ROP), and atom transfer radical polymerization (ATRP), and post-polymerization has also been used. The applications include the formation of nanostructured materials, magnetic materials, redox recognition and sensing, lithographic patterning, antimicrobial materials, stimuli-responsive materials, catalysis and electrochemical devices.