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 “worm-type” 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.