Building molecular frameworks with tailored pore structures

Interest in materials made from molecular components, driven by the promise of new systems with precisely tailored properties, is accelerating at a rapid pace. The last decade has witnessed tremendous advances in the sophistication of molecular materials based on supramolecular building blocks that can be interchanged at will to generate materials with properties and function that can be finely tuned in a systematic manner. This is exemplified here by examples that illustrate the role of hydrogen bonding in generating low-density 'porous' frameworks capable of forming lamellar host-guest inclusion compounds with tunable inclusion cavities and solid-state architectures, topologically related tube-like structures and two-dimensional porous molecular monolayers with structures mimicking layered motifs in molecular crystals. These systems demonstrate that low-density molecular frameworks can be systematically engineered to generate rather predictable and robust structures, particularly if they possess an intrinsic softness that enables the frameworks to self-optimize the non-covalent interactions governing their supramolecular architectures.