SINGLE TURNOVER (STO) REACTION PROCEDURE AND THE CHARACTERIZATION OF THE ACTIVE-SITES ON SUPPORTED METAL-CATALYSTS

The results presented here show that the STO reaction sequence can provide surface characterization data for dispersed metal catalysts. With this procedure it is possible to identify and quantify five different types of sites on the catalyst surface. It appears that for most synthetically useful catalytic processes the most important of these sites are the three different kinds of STO saturation sites. As might be anticipated from mechanistic considerations these saturation sites are the more coordinatively unsaturated corner atoms or adatoms on the metal surface. These sites are considered to be surface complexes composed of the central active metal atom surrounded by its neighbouring metal atom "ligands". Applying angular overlap calculations to the resulting species gives Frontier Molecular Orbital information for each type of surface site. These data are useful in developing more complete mechanistic understanding of the various types of surface reactions promoted by dispersed metal catalysts.