(3ce) Understanding Catalysis Through Organic-Inorganic Hybrid Catalytic Materials

The design of metal cluster or nanoparticle catalysts that are both sinter-resistant (stable) and that have tunable electronic properties enables the understanding of structure-function relationships in heterogeneous and homogeneous catalysis.  It also provides a method to tune the activity and selectivity of real-world catalysts by overcoming one of the major stumbling blocks for cluster catalysts – deactivation via sintering.  I investigate the use of organic ligands, such as calixarenes, to control catalytically active noble metal sites on metal oxide supports and in homogeneous solution, utilizing an approach that is conceptually similar to that used by enzymes to control reactivity though organic side-chains acting as ligands.  Noble metal catalysts have been synthesized with calixarene ligands bound to the metal nanoparticle yet still demonstrate reactant accessibility to the metal nanoparticle surface as measured by chemisorption probe experiments.  Catalytic activity has been demonstrated for these using several different reaction systems such as reduction and oxidation reactions on these noble metal catalysts.  Results provide a unique perspective into the structure-activity relationships present in catalysis.