Aminophosphine–palladium(II) complexes: Synthsesis, structure and applications in Suzuki and Heck cross-coupling reactions

Reaction of furfurylamine with 1 or 2 equivalents of PPh2Cl in the presence of Et3N, proceeds under anaerobic conditions in thf to give furfuryl-2-(N-diphenylphosphino)amine, Ph2PNHCH2-C4H3O, 1 and furfuryl-2-(N,N-bis(diphenylphosphino)amine), (Ph2P)2NCH2-C4H3O, 2, respectively. The reactions of 1 and 2 with MCl2(cod) (M = Pd, Pt; cod = 1,5-cyclooctadiene) or Pt(CH3)2(cod) yield complexes [M(Ph2PNHCH2-C4H3O)2Cl2] (M = Pd 1a, Pt 1b), [Pt(Ph2PNHCH2-C4H3O)2(CH3)2] (1c), and [M((Ph2P)2NCH2-C4H3O)Cl2] (M = Pd 2a, Pt 2b), [Pt((Ph2P)2NCH2-C4H3O)(CH3)2] (2c), respectively. All the compounds were isolated as analytically pure substances and characterized by NMR, IR spectroscopy and elemental analysis. Representative solid-state structures of 2a and 2b were also determined by X-ray single crystal diffraction technique. Furthermore, the palladium complexes 1a and 2a were tested and found to be highly active catalysts in the Suzuki coupling and Heck reaction affording biphenyls and trans-stilbenes, respectively.

We describe the coordination chemistry of the two furfurylamine-functionalised aminophosphine ligands with selected transition–metals. The structures of all new compounds have been elucidated by a combination of multinuclear NMR spectroscopy, IR spectroscopy, elemental analysis and by X-ray crystallography. In addition, we tested the catalytic activities of Pd(II) complexes as potential catalyst in the Suzuki–Heck type coupling reactions.Figure optionsDownload as PowerPoint slideHighlights
► Pd(II) and Pt(II) complexes with the NH–P and NPP ligands were synthesized.
► The structures of two complexes were elucidated by X-ray diffraction.
► The palladium complexes were tested in the Suzuki coupling and Heck reaction.