Molecular templates and nano-reactors: two-dimensional hydrogen bonded supramolecular networks on solid/liquid interfaces

With tunable cavities, the two-dimensional (2D) hydrogen bonded supramolecular networks are receiving increasing attention in surface supramolecular chemistry during the past decade. Herein, we give a brief account of our efforts on the 2D supramolecular host-guest chemistry based on molecular networks connected by hydrogen bonds, with an aid of scanning tunnelling microscopy (STM) technique. Following the molecular assembling, we have constructed a group of two-dimensional H-bonded supramolecular networks with cavities of different sizes, shapes, and symmetry characteristics on HOPG surface. Our researches have reported that these open porous structures could serve as molecular templates to host alien ensembles, as molecular sieves for molecular separation and recognition, as molecular sensors for ion detections, and as spatial confiners to control chemical reactions. It can be noticed that the interactions between host templates and guest molecules are emphasized throughout this review. On the basis of the confinement of supramolecular networks, it could be less problematic to explore the controllability, predictability, stability and applicability of the ordered structures.