title: Dendrimer-encapsulated Pd nanoparticles as catalysts for C-C cross-couplings in flow microreactors.
abstract: The inner walls of glass microreactors were functionalized with dendrimer-encapsulated Pd nanoparticles. The catalysts were efficient for the Heck-Cassar (copper-free Sonogashira) and Suzuki-Miyaura (SMC) cross-coupling reactions. For the Heck-Cassar reaction between iodobenzene and phenylacetylene, the catalytic system exhibited a high turnover frequency (TOF) and on average required milder reaction conditions as compared to other continuous flow cross-couplings. A study of the substituent effect of para-substituted aryl halides revealed a beneficial effect of electron-withdrawing side groups for the SMC. Moreover, a reaction constant (ρ) of 1.5, determined from the Hammett plot, indicated a possible rate-determining step other than the oxidative addition.
authors: Laboratory of Molecular Nanofabrication, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands. w.verboom@utwente.nl.
authors: Roberto
authors: R
authors: Ricciardi
authors: Jurriaan
authors: J
authors: Huskens
authors: Willem
authors: W
authors: Verboom