Heck and Suzuki-Miyaura couplings catalyzed by nanosized palladium in polyaniline

A novel route to prepare polyaniline (PANI)-supported Pd(0) nanoparticles by a one-pot chemical route is presented. Nanosized Pd(0) particles were first prepared by reduction of Pd(OAc)(2) using t-BuONa activated sodium hydride in refluxing THF. A ligand exchange with aniline on t-BuONa-stabilized Pd(0) particles yielded aniline-stabilized particles. Pd(0)/PANI nanocomposites were finally obtained by polymerizing aniline-stabilized Pd(0) particles using ammonium persulfate. Nanocomposites were characterized by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Results show that this one-pot experimental route is successful in producing hybrid materials constituted of Pd(0) nanoparticles stabilized by PANI due to the strong binding of PANI amine groups to Pd(0) particles. TEM images of the nanohybrids show that metal particles with diameters of ca. 4.9 nm are homogeneously dispersed in PANI. The preliminary results indicate that the Pd(0) particles supported on PANI behave as efficient heterogeneous catalysts in the Heck and Suzuki-Miyaura reactions of aryl iodides. Copyright (c) 2005 John Wiley & Sons, Ltd.