Mixed phosphine/N-heterocyclic carbene-palladium complexes: synthesis, characterization, crystal structure and application in the Sonogashira reaction in aqueous media

摘要

A series of 2-hydroxyethyl-substituted N-heterocyclic carbene-(NHC)PdX2PPh3 complexes have been synthesized by substitution of the pyridine or 3-chloropyridine ligand in (NHC)PdX2(pyridine/3-chloropyridine) complexes with triphenylphosphine. The new complexes were characterized by H-1, C-13 {H-1}, P-31 {H-1}NMR, FTIR spectroscopy and elemental analysis. Also, the molecular and crystal structures of 1c and 1d have been obtained by single-crystal X-ray diffraction. The 2-hydroxyethyl-substituted (NHC)PdX2PPh3 complexes have been examined as catalysts for the Sonogashira cross-coupling reaction in water/DMF solvent mixtures.