Organic host-guest molecular assemblies

The utility of materials possessing molecular-scale porosity has been amply demonstrated by the use of inorganic zeolite frameworks as functional cata lysts, separating media, and novel electronic materials. This has prompted an increase in the development of porous organic host materials capable of including guest molecules within their pores, thereby mimicking the behavio r of inorganic zeolites. Such organic host-guest complexes may prove to be superior to their inorganic counterparts in some applications because they are formed spontaneously by self-assembly from molecular building blocks th at can be customized through organic synthesis, yielding host structures in which the pores have precisely defined size, shape and composition. Howeve r, in order to design and synthesize host-guest complexes possessing unique and useful properties it is essential to control the assembly of molecules into preordained, desirable solid-state architectures. Understanding how m olecules arrange in the solid state and using this information rationally t o 'engineer' solid-state properties is essential to numerous technologies, including electronics, optoelectronics, sensors, information storage, and c hemical separations. (C) 2000 Published by Elsevier Science Ltd.