Mixed phosphine/N-heterocyclic carbene palladium complexes: synthesis, characterization and catalytic use in aqueous Suzuki-Miyaura reactions.

A series of N-heterocyclic carbene (NHC)/PR3 palladium(II) and palladium(0) complexes has been synthesized and fully characterized. X-ray crystallographic data have allowed comparison of ligand steric properties. The NHC ligand was found to vary its steric properties as a function of the phosphine co-ligand.

Room-temperature activation of aryl chlorides in Suzuki-Miyaura coupling using a [Pd(micro-Cl)Cl(NHC)]2 complex (NHC = N-heterocyclic carbene).

A straightforwardly synthesised complex, [Pd(micro-Cl)Cl(NHC)](2) (NHC = bis(2,6-diisopropylphenyl)imidazol-2-ylidene, IPr), has been employed to mediate Suzuki-Miyaura reactions involving aryl chlorides at very low catalyst loadings and at room temperature.