Polymer-Bound Phosphine Catalysts

Abstract

While the theme of this volume is catalysis in a single phase, the principles and dynamics of homogeneous catalysis have impacted other areas of catalysis as well. Today, more than ever, there is an overlapping, a meshing of concepts from homogeneous and heterogeneous catalysis. One of the areas that interfaces both classical divisions is catalysis via polymer-bound transition metal complexes. It is an interface area because catalysts are prepared typically from an organic polymer such as polystyrene and then, after attachment of a ligand, a soluble metal complex is bound. The choice of metal complex is almost always based upon examples from homogeneous catalysis. One of the principal motivations for attaching a soluble complex to a polymer is that catalyst recovery becomes much easier. There are, however, motivations beyond simple recovery considerations for examining the reactions of polymer-bound catalysts. Though the characteristics of the polymer-bound phosphines may be described to a first approximation as being predictable on the basis of the properties, performances, and mechanistic interpretations of the homogeneous analogs, the support often has a significant influence on catalytic activity. For example, a polymerbound catalyst may give a product distribution quite different from that of the soluble catalyst. Moreover, it is often observed that polymer-supported catalysts are less oxygen sensitive than the homogeneous ones.KeywordsHomogeneous CatalystUnited States PatentHomogeneous CatalysisPolymeric CatalystMatrix IsolationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.