Metallo-supramolecular capsules

The formation of capsule based architectures on the molecular scale has been of interest to many researchers in recent times. The formation of these assemblies is often challenging and can produce structures on a multi nano-metre scale that can serve specific functions. Some of the approaches used to produce such assemblies are outlined in relation to various building blocks in metal-organic polyhedra, molecular boxes and molecular capsules for example. The last of these has been the focus of our recent studies since the discovery of a hydrogen-bonded nano-capsule based on C-methylresorcin[4]arene, although the molecule also assembles in dimeric capsule motifs. The related pyrogallol[4]arenes display similar behaviour, however a number of metal-organic analogues have recently been synthesised and characterised through a variety of techniques that suggest various assembly processes. These are highlighted in the context of related architectures in order to give a sense of potential for such assemblies that can, in some cases, be assembled instantaneously or very rapidly. (c) 2007 Elsevier B.V. All rights reserved.