Characterization of a Poly-4-vinylpyridine-Supported CuPd Bimetallic Catalyst for Sonogashira Coupling Reactions.

CuPd bimetallic Solvated Metal Atoms (SMA) synthesized by metal vapor synthesis (MVS) technique and supported on poly-4-vinylpyridine (PVPy) resin, showed signicantly higher catalytic activity in Sonogashira-type carbon-carbon coupling reactions than the corresponding monometallic Cu and Pd systems as well as their physical mixture. The analysis of the bimetallic catalyst combining high-resolution transmission electron microscopy (HRTEM) and x-ray absorption ne structure (XAFS) spectroscopy revealed the presence of small Pd nanoparticles (dm = 2.5 nm) while the analysis of the x-ray absorption data, at the Cu K-edge, showed that a relevant part of Cu atoms were in Cu2+ oxidized phase suggesting the formation of thin and incomplete Cu oxide layers around the Pd-rich cores.