Synthesis and Polymerization Performance of PdII Complexes of New 2-Hydroxyethyl-Substituted Diphosphane Ligands

We have synthesized a new diphosphane ligand, 1,3-bis[(2-hydroxyethyl)(phenyl)phosphanyl]propane (2*) (*: mixture of meso- and racemic diastereoisomers), and its corresponding neutral dichloro palladium(II) (3*), diiodo palladium(II) (4*), and dicationic diacetonitrile palladium(II) ditetrafluoroborate (5 *) complexes. Separation of the 4 rac and 4 meso diastereoisomers was achieved by column chromatography and subsequent crystallization. Assignments of the particular complex geometries of 3 meso and 4 rac were facilitated by single-crystal X-ray diffraction analysis, After activation with MAO, complex 3* exhibits superior activity in the homopolymerization of 2-norbornene relative to that of the dichloro Pd-II derivative of 1,3-bis(diphenylphosphanyl)propane (dppp). Compound 5* and the dppp-analogue possess similar catalytic potentials in ethylene/CO copolymerization experiments. Applying complex 5* to propylene/CO copolymerization leads to highly regio- and predominantly stereoregular polyketone materials. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).