Water-Soluble Palladium Nanoclusters as Catalysts in Ligand-Free Suzuki-Miyaura Cross-Coupling Reactions

This Letter reports Pd-nanocluster catalysts and their formation in ligand-free Suzuki-Miyaura reactions with palladium(II) nitrate as a precatalyst. The catalysts are water-soluble neutral Pd tetramer and trimer in their singlet electronic states, as identified by UV-vis absorption spectroscopy, and are formed by leaching of spherical Pd(0) nanoparticles with an average diameter of about 3 nm. The Pd(0) nanoparticles are produced by reducing palladium(II) nitrate and characterized with transmission electron microscopy and Pd K-edge extended X-ray fine structure spectroscopy. The Pd(II) reduction is induced by ethanol, enhanced by potassium hydroxide, and monitored with X-ray photoelectron spectroscopy.

Automated summary

This research reports the formation of Pd-nanocluster catalysts and their involvement in ligand-free Suzuki-Miyaura reactions. The catalysts are formed by leaching spherical Pd(0) nanoparticles with an average diameter of about 3 nm, and they are soluble in water. The reduction of Pd(II) is induced by ethanol and enhanced by potassium hydroxide.