The bidentate ligand anthranilic acid has been anchored to polystyrene beads (Amberlite XAD-4) and the Rh(1) complex has been prepared. The polymer is a hydrogenation catalyst of exceptional activity, long-term stability, and considerable insensitivity to poisoning. Hundreds of catalytic cycles per metal atom are demonstrated without substantial loss of activity. The rhodium catalyst reduces a variety of olefinic and aromatic hydrocarbons and carbonyl, nitrile, and nitro functional groups. Catalytic activity depends upon retention of beads; if fragmentation occurs, the activity is considerably diminished. ESCA studies clearly demonstrate the rhodium to have a +1 formal oxidation sr;ate.Anchoring ligands to insoluble polymeric supports, followed by complexation with transition metals, results in polymers having catalytic p~t e n t i a l . l -~ These metal complexes, hybrids of homogeneous and heterogeneous approaches, are attractice because they often permit the activity of soluble catalysts and the ease of product separation inherent in heterogenecus catalysts. In referring to this class of catalysts the names "polymer bound", "hybrid phase", or "supported" are common.The choice of the ligand to be anchored is usually based on attempts to create environments analogous to those in the most active homogeneous catalysts. Because of the preponderance of phosphine complexes in homogeneous catalysts, most polymer-bound catalysts to date have involved these

Chlormethyliertes Polystyrol (I) liefert mit Anthranilsäure das polymere Substitutionsprodukt (II), das mit Rh(III)‐chlorid zu einem polymeren Rhodium‐ Katalysator führt.