Palladium-Allyl Phosphoramidite Complexes: Solid-State Structures and Solution Dynamics

Several mono-phosphoramidite and bis-phosphoramidite 2-methallyl and 1,3-diphenylallyl allyl complexes of Pd(II) have been prepared. The solid-state structure for one of these has been determined. The mono-phosphoramidite chloro-allyl complexes of Pd(II) exist in two isomeric forms in solution. 1H,1H NMR exchange spectroscopy reveals that the dinuclear species [Pd(μ-Cl)(η3-CH2C(Me)CH2)] 2 is involved in the interconversion between the two isomers. There is evidence to suggest that phosphoramidite dissociation is not responsible for this exchange. The cationic η3-2-methallyl bis-phosphoramidite Pd complexes reveal nonequivalent 31P resonances, as a consequence of slow allyl dynamics and in agreement with the preliminary X-ray structure.