Molecular sieves as host materials for supramolecular organization

The use of zeolites and mesoporous silicas (M41S family) as host materials for the supramolecular organization of organic dye molecules, metal sulfide clusters, and transition metal complexes is reviewed. For dye-zeolite systems, different stages of organization are discussed, ranging from the arrangement of the dyes in the zeolite channels to the specific adsorption of molecules at the channel entrances and finally to the coupling of the dye zeolite crystals to an external device. The synthesis of metal sulfide nanoparticles in zeolites is illustrated by our studies of silver sulfide clusters in zeolite A. Starting from an activated Ag+-loaded zeolite, the synthesis exploits the defined structure of the zeolite framework to achieve controlled cluster growth yielding composites with unique luminescence properties. The organization of guest species in mesoporous silicas of the M41S family is mostly related to the chemistry of the surface silanol groups. This aspect is discussed with particular emphasis on the functionalization with organic chromophores and the grafting of isolated transition metal centers through oxo-bridges. (C) 2004 Elsevier Inc. All rights reserved.