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 ra pid pace. The last decade has witnessed tremendous advances in the sophisti cation of molecular materials based on supramolecular building blocks that can be interchanged at will to generate materials with properties and funct ion that can be finely tuned in a systematic manner. This is exemplified he re by examples that illustrate the role of hydrogen bonding in generating l ow-density 'porous' frameworks capable of forming lamellar host-guest inclu sion compounds with tunable inclusion cavities and solid-state architecture s, topologically related tube-like structures and two-dimensional porous mo lecular monolayers with structures mimicking layered motifs in molecular cr ystals. These systems demonstrate that low-density molecular frameworks can be systematically engineered to generate rather predictable and robust str uctures, particularly if they possess an intrinsic softness that enables th e frameworks to self-optimize the non-covalent interactions governing their supramolecular architectures. Copyright (C) 2000 John Wiley & Sons, Ltd.