ABSTRACTOrganic-inorganic hybrids exhibiting specific properties are easily prepared
by incorporation of organic fragments in an inorganic network. Increasing
attention is being paid to hybrid silsesquioxane gels, which are prepared by
sol-gel hydrolysis condensation of organic molecules containing two or more
trialkoxysilyl substituents. These hybrids consist of a mixed
three-dimensional network, where the organic fragment, cross-linking
siloxane chains, is part of the framework. Owing to the presence of a strong
Si-C bond between the organic and the inorganic fragments, highly stable
hybrid network are produced in this way. A variety of materials can be
produced according to the intrinsic properties of the organic. We report
here the preparation of hybrid materials with complexing properties upon
hydrolysis-condensation of ligands functionalized by Si (OR)3
groups. New hybrid silica based materials containing malonamide ligands have
been prepared by sol-gel hydrolysis condensation of functionalized
precursors and have been used as solid phase extractants for the
complexation of actinides. This approach is quite different from the
classical immobilization procedure of complexing agents. The sol-gel
approach allows one to adjust the ligand loading and to achieve some control
and some tuning of the ligand environment since the oxide matrix is built
around the complexing moieties. These hybrids proved to be highly efficient
extracting solids.