New synthetic methods to efficient nanoporous and nanostructured catalysts: Self-assembly and co-assembly of multiple site-isolated catalytic sites on mesoporous materials

The introduction of organic groups into nanoporous materials results in functionalized nanostructured heterogeneous catalysts. By various self-assembly routes including a new solvent-assisted grafting and co-assembly of multiple types of organic groups, we and others have recently demonstrated the synthesis of a broad range of nanoporous catalysts containing high surface areas, site-isolated catalytic sites, nanometer pores and efficient and selective catalytic properties for various types of reactions. The grafting of site-isolated organic groups with a polar solvent such as ethanol or isopropanol is among the newest synthetic strategies that allow the synthesis of novel heterogeneous catalysts with enhanced catalytic efficiency. While the distributions and site-isolation of the catalytic sites in these materials can be controlled simply by changing the solvents used for grafting the catalytic functional groups, the degree of site-isolation of the catalytic sites can be probed by a simple new colorimetric method involving measuring of the d-d electronic spectra of metal complexes with the catalytic sites. By introducing appropriate secondary functional groups into the nanoporous catalyst structure, selective catalysts for specific reactants can also be produced. Furthermore, by a judicious choice of the active catalytic sites, selectivity for a specific product by these catalysts has been demonstrated recently.