CATALYSTS AND BIOCATALYSTS ANCHORED TO INORGANIC SUPPORTS

The review deals with transition metal complexes and enzymes chemically bonded to inorganic supports by means of silyl-substituted anchoring ligands. The synthesis of these functionalization agents, the effect of immobilization procedure, the length of spacer, the texture of support and the structure of anchoring ligand are mentioned. Conclusions based on kinetic studies of the efficiency and selectivity of immobilized catalysts in hydrogenation, hydrosilylation, isomerization, polymerization and enzymatic reactions are discussed. Proposed mechanisms of the action of these catalysts are supported by the results of IR, NMR, ESCA and ESR studies. The attention is paid to the leaching and deactivation of catalysts, to the other types of immobilized catalysts such as those anchored via polymer ligands or via ligands in molten phase as well as to the effect of support texture and particle shape, to prepare the catalysts with limited nonspecific sorptions and long lifetime.