Controlling Heterogeneous Catalyst Selectivity Using Grafted Metallocalixarene Active Sites

Control of the open versus closed coordination environment surrounding grafted metal cations as Lewis-acid catalysts is central to the grand-challenge theme of molecular control of catalysis on surfaces.  This has been achieved by using a calix[4]arene macrocycle and silica that both enforce the coordination environment surrounding the metal center as well as site isolation of the molecular supported active site.  We demonstrated control of the coordination environment surrounding the grafted Lewis acid center as well as show the relevance of datively coordinated alkyl hydroperoxide within the epoxidation mechanism (i.e. kinetic consequences of covalent versus dative attachment of peroxide to Lewis-acid site).