Stable Palladium(0), Palladium(II), and Platinum(II) Complexes Containing a New, Multifunctional and Hemilabile Phosphino−Imino−Pyridyl Ligand: Synthesis, Characterization, and Reactivity

The new, multifunctional, hemilabile phosphorus−bis(nitrogen) ligand N -(2-(diphenylphosphino)benzylidene)(2-(2-pyridyl)ethyl)amine, PNN, containing phosphine, imine, and pyridyl donor groups and alkyl-, allyl-, and acylpalladium complexes, methylplatinum complexes, and a zerovalent palladium complex containing PNN have been synthesized and characterized with 1 H-, 13 C-, 31 P-, and 15 N-NMR. PNN commonly coordinates in a terdentate fashion, resulting in ionic complexes of the type [(PNN)M II (R)]Y (M = Pd, Pt, R = CH 3, Y = Cl, CF 3 SO 3; M = Pd, R = C(O)CH 3, Y = CF 3 SO 3; M = Pd, R = η 1 -CH 2 C(H) CH 2, Y = Cl, CF 3 SO 3 ). Bidentate coordination of PNN is observed for [(PNN)Pd II (η 3 -(CH 3 ) 2 CC(CH 3 )C(CH 3 ) 2 )]Cl and surprisingly also for neutral (PNN)Pd II (C(O)CH 3 )(Cl). An unprecedented zerovalent palladium complex (PNN)Pd 0 has been isolated, which is stabilized by PNN only. Preliminary results show that palladium complexes of PNN are very active in allylic alkylation reactions.