Organic Polymers, Oligomers, and Catalysis
Porphyrins are common ligands for transition metals, allowing performing catalytic reactions in organic solvents. In the early 20th century, polymers were thought to be composed of aggregated colloids from small molecules. This chapter offers an overview of current and emerging strategies used for performing homogeneous and heterogeneous catalysis with the help of polymers, oligomers, and dendrimers. In spite of the fact that porous inorganic supports hold the leads in supported catalysis field, polymer supports have also attracted significant attention due to their capability for providing original and adaptive design strategies. Homogeneous catalytic processes, where both the catalyst and the reactants share the same phase, are generally more active and selective than their heterogeneous counterparts. Employment of homogenous catalysis is, however, growing rapidly, predominantly within the polymer and pharmaceuticals industries. Cross-linked polystyrene is probably the most popular polymeric platform for catalyst immobilization, and played a key role in the development of peptide synthesis and combinatorial chemistry.