Coordination directed metal covalent organic frameworks

Metal covalent organic frameworks (MCOFs) as a bridge between covalent organic frameworks (COFs) and metal organic frameworks (MOFs) have recently attracted much attention. Though the COFs with metal ions in their covalent skeleton achieved either by pre-synthetic or post-synthetic metalation can all be regarded as MCOFs, herein, we have specifically focused on the design and synthesis of MCOFs, starting from coordination compounds with the template effect. Noteworthily, coordination directed synthesis offers a powerful tool of making complex architectures from simple precursors, such as catenanes, rotaxanes, Borromean rings, Solomon knots, and metal organic cages. Nevertheless, the construction of MCOFs using coordination compounds underlying the coordination directed synthesis and reticular chemistry is still challenging, and only limited examples have been realized. This review will highlight the coordination directed MCOFs including their structural design, functional strategy, and potential applications. Finally, some major challenges and perspectives of MCOFs are discussed in the hope of promoting the continued development of this emerging field.