Palladium(II) complexes of a bis-2-aminobiphenyl N-heterocyclic carbene:: Synthesis, structural studies and catalytic activity

A new imidazolinium [(SIBiphen)H](BF4) was synthesized in three steps from 2-aminobiphenyl. The reaction of the salt with Pd(OAc)(2), NaI and t-BuOK gave a dimeric Pd(II) complex [(SIBiphen)PdI2](2), which was analyzed by an X-ray diffraction study. The reaction of [Pd(allyl)Cl](2), the imidazolinium salt and t-BuOK in THF at -78 degrees C gave the monomeric Pd complex, in which the N-heterocyclic carbene was bound to the metal centre, as confirmed by a single-crystal X-ray diffraction study. A preliminary catalytic study showed that these new systems were moderately active in the Suzuki-Miyaura coupling of aryl halides. (c) 2006 Elsevier B.V. All rights reserved.