Solvent-free on-surface synthesis of boroxine COF monolayers.

A protocol is proposed for the solvent-free on-surface synthesis of covalent organic framework monolayers by condensation of diboronic acids. Monomers are vapor-deposited and water is used for equilibrium regulation. Samples are characterized on progressively smaller length scales by light microscopy, Scanning Electron Microscopy, and Scanning Tunneling Microscopy.