Design of metal ion-catecholate complexes towards advanced materials

Metal ion-catecholate complexes (MCCs) extensively exist in plants and animals, which are in charge of versatile biological functions, such as constructing organs, controlled releasing metal ions and antibacterial. Inspired by this, researchers have exploited various kinds of artificial MCCs, which can serve as structural and functional synthons to construct advanced materials. In terms of the structural contribution, these complexes exhibit not only physical interactions, including metal-coordination, hydrogen bonding, π-π stacking and cation-π interactions, but also rich chemical reactions, including radical polymerization, Schiff base reaction and Michael addition. In terms of functional contribution, the complexes can endow the materials with the intrinsic properties of polyphenols and metal ions, including antioxidant, adhesion, antibacterial, bioimaging and catalyst. In addition, some emerging and fantastic functions are also originally from the complexes, such as tunable mechanical property, self-healing, controlled release and photothermal effect. In this review paper, we comprehensively discuss the recent development of MCC-based materials, including coatings, particles, metallogels and metal–organic frameworks (MOFs). Perspectives in this field has also been put forward as well.