Metal-organic nanotubes: Designs, structures and functions

[Display omitted] •Metal organic nanotube.•Synthetic strategies.•Formation mechanism.•Crystal structures.•Properties. This tutorial review provides basic design principles and the current status of metal-organic nanotubes (MONTs). As an attractive family of nanotubular materials, MONTs can show precise structures that can be designed and constructed through judicious choice of metal ions and ligands, and also interesting physical and chemical properties that can be embedded within the structures. This review summarizes the recent progress in this topical field including the synthetic approaches towards the nanotubular structures, the formation mechanism, the crystal structures of MONTs reported thus far with finite and infinite sizes, and also the physical and chemical properties. The review concludes with a discussion of future challenges for development of this promising field.