SYNTHESIS OF BIS(PHOSPHANE) PALLADIUM AND RHODIUM COMPLEXES ON A POLYETHYLENE OXIDE GRAFTED POLYSTYRENE MATRIX (TENTAGEL) AND THE CATALYTICBEHAVIOR OF THE RHODIUM COMPLEXES

A new polymer-attached rhodium catalyst on a polyethylene oxide-grafte d styrene matrix (TentaGel) is described. The corresponding anchor mol ecules were prepared by starting from different Boc-protected chiral p yrrolidinebis(phosphane)Pd complexes. The crystal structure of )-N-(4- carboxybutanoyl)-3,4-bis(diphenylphosphanyl diiodopalladium (1c) was d etermined. The formation of an amide bond between TentaGel and anchor molecules resulted in polymer-bound Pd bisphosphane complexes. Decompl exation of the Pd with cyanide and reaction of the free polymeric liga nd with [Rh(COD)(2)]BF4 led to the active hydrogenation catalyst. The influence of different solvents on the swelling volume and the catalyt ic behavior was tested. The polymer-bound rhodium complex -TentaGel-am ino-pentyl)-3,4-bis(diphenylphosphanyl pyrrolidineP,P'] (1,5-cycloocta diene)rhodium tetrafluoroborate (7) has about the same catalytic activ ity and enantioselectivity as the homogeneous complex onyl)-3,4-bis(di phenylphosphanyl)pyrrolidine-P,P'] (1,5-cyclooctadiene)rhodium tetrafl uoroborate (9) in the same solvent mixture. It is possible to reuse 7 once, then it abruptly loses activity. This behavior remains to be cla rified.