Wide bite angle diphosphines: Xantphos ligands in transition metal complexes and catalysis

The reactivity of organotransition metal complexes is dependent on the liga nd environment of the metal. This Account describes the development and app lication of new diphosphine ligands, designed to induce large P-M-P angles in transition metal complexes. Aided by computational chemistry, a homologo us range of diphosphines based on rigid heterocyclic aromatic backbones of the xanthene-type with natural bite angles of similar to 100-134 degrees ha ve been developed. The special structure of the ligands has an enormous imp act on stability and reactivity of various transition metal complexes. High ly active and selective catalysts have been obtained by influencing this re activity.