Supramolecular host-guest systems in zeolites prepared by ship-in-a-bottle synthesis

Zeolites have a microporous system defining large cavities interconnected by smaller windows. These cages can accommodate large molecules whose size, however, can be too big to cross the windows. The most important examples of these tridirectional zeolites are faujasites X and Y, but examples of other suitable zeolites are Beta, EMT and MCM-22. The inclusion of large guests inside the cavities starts from smaller precursors that can diffuse through the zeolite pores and then react inside the cavities to form the target guest. This microreview discusses the special characterisation techniques necessary to study these systems, differentiating those that serve to assess the identity and purity of the guests from those that address the internal vs. external location of the guests with respect to the zeolite host. It is organized by grouping the examples of ship-in-a-bottle synthesis according to the potential application of the system as catalysts, photocatalysts, sensors, in molecular machines, etc. Although proper credit is given to the pioneering reports on ship-in-a-bottle synthesis, the emphasis is placed on the most recent examples of the literature covering up to mid 2003. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.