Solid phase host-guest properties of cyclodextrins and calixarenes covalently attached to a polysilsesquioxane matrix

A new family of silicon-based polymers has been prepared with covalently bound hosts. The polymer is a polysilsesquioxane formed by the sol-gel process, and the hosts are cyclodextrins (CD) or calixarenes (CX). The organic and silicon structures are supported by solid-state NMR spectroscopy. The nanoporous polymer is relatively stable to a variety of aqueous conditions. It is a water-insoluble material, which binds with and extracts both organic compounds and metal cations from water. The polymer containing the guests is then removed by filtration. The objective achieved can be either removal of impurities from water or recovery of materials dissolved in water. The CD-based polymer may be renewed by treatment with ethanol. Its binding ability is equal or superior to that of other available materials such as activated charcoal.