Palladium(II) complexes of bis(diphosphene) with different coordination behaviors.

Organophosphorus compounds possessing a P-P double-bond character are intriguing materials in coordination chemistry because it is possible to form a variety of coordination modes from the π-bond in addition to the lone pairs. We report herein the complexation of a new bidentate ligand, ethylene-tethered bis(binaphthyldiphosphene) ( S , S )-2, with palladium(II) species. The reaction of ( S , S )-2 with [Pd(π-allyl)(cod)](SbF 6 ) and PdCl 2 (cod) afforded η 1 /η 1 -bis(diphosphene) complex 7 and η 1 -diphosphene/η 2 -phosphanylphosphide complex 8, respectively. The latter was characterized by a chloride migration from the palladium atom to a phosphorus atom due to the high electron-accepting character of the PP moiety. Theoretical calculations revealed the migration process and nature of complex 8.