Putting aromatic compounds to work: Rational synthesis of organic 2D polymers

This contribution describes two different approaches aimed at the synthesis of monolayer molecular sheets with internal order, or, in other words, 2D polymers. First, an interfacial strategy is presented in which terpyridene-based hexafunctional monomers spread at the air/water interface are connected to one another with the help of metal salts. While this approach leads to micrometer-sized monolayer sheets that are mechanically stable enough to be spanned over several micrometer-sized holes, their internal structure could not yet be proven. The second approach rests upon solid-state photochemistry, and properly designed monomers are covalently connected with one another while being held in layered geometries owing to crystal packing. Exfoliation to single sheets can be achieved, and molecular structure is supported by a Raman spectroscopic analysis. We consider this the first case of a rational synthesis of 2D polymers and briefly touch on the impact this may have.