Cyclodextrin-based porous silica materials as in situ chemical "nanoreactors" for the preparation of variable metal-silica hybrids

Inclusion complexes of cyclodextrins with organometallic coordination compounds of Pd, Pt, Rh, Fe, Ni, and Ru have been used to produce porous metal-silica hybrid materials. The cyclodextrins are templates for the structure of the silica and lead to a uniform "wormtype" pore system. After the templating step the organometallic compounds can be employed as in situ precursors for the preparation of metal nanoparticles within the pore system, thus leading to a one-step synthesis of silica-supported metal catalysts. These new materials are characterized and how the chemical confinement of the silica pores can influence the size, structure, and distribution of the nanoparticles is studied.