This award in the Inorganic, Bioinorganic, and Organometallic Chemistry program supports research on silica-related compounds by Dr. Frank J. Feher, Chemistry Department, University of California-Irvine. Synthetic methods for three types of silsesquioxane compounds will be developed: incompletely-condensed silsesquioxanes from fully-condensed (RSiO3/2)n frameworks; versatile precursors to water-soluble frameworks; and endohedral complexes. The goal is to develop methods for preparing the target compounds in bulk for use in catalytic reactions. A key step in all of these syntheses is selective partial hydrolysis of fully-condensed frameworks to give well-defined products. Some of the resulting compounds will be studied as models for surface reactions thought to occur at catalyst sites with various numbers of proximate hydroxy groups or at sites that control stereospecificity. Others will be used to form `cages` that can host small molecules, thus controlling reactivity. Large assemblies of compounds containing silicon and oxygen called silsesquioxanes have previously been synthesized and used as models for silica and as building blocks for other network solids. Compounds of this type are used as catalyst supports for transition metals and as catalysts in important industrial processes. In this research, new compounds in this family will be prepared in order to extend the usefulness of this inexpensive class of materials.
