Palladium Iminoacyl Imine Complexes: Strategies toward Imine Insertion

The syntheses and characterization of a number of palladium complexes containing imine and/or iminoacyl groups are reported. Our strategies toward the insertion of imines into palladium iminoacyl complexes are outlined. The imine complexes [Pd(Me)(L2){N(R′)C(H)Ph}]X (where L2 = dppe, dppp, dppf; R′ = Ph, Me, Bz; and X = BF4 or OTf) were prepared and fully characterized. [Pd(Me)(dppe){N(Ph)C(H)Ph}]BF4 (1) and [Pd(Me)(dppp){N(Ph)C(H)Ph}]OTf (4) were structurally characterized by X-ray crystallography. The iminoacyl-imine complexes [Pd{C(Me)NXyl} (L2){NC(Me)OCH2CH2}]BF4 (L2 = dppe, 12; dppp, 13) were prepared. The bis-imine complex [Pd(dppe){NC(Me)OCH2CH2}2][BF4]2 (14) resulting from disproportionation of 12 was also prepared and structurally characterized. Protonation of the iminoacyl fragment provided iminoacyl imine complex [Pd{C(CH3)N(H)Xyl}(dppe){N(Bz)CPhH}][BF4]2 (17), which was sufficiently stable to be structurally characterized, providing some insight into the coordination of these fragments to palladium.