Effect of chloride ions on allylic diphosphine palladium (II) complexes:: NMR characteristics and chemical reactivity

A systematic study of the effect of chloride ions on the NMR characteristics of several cationic diphosphine eta(3)-allyl palladium complexes has revealed in some instances a deshielding of the protons. Chloride ions also enhance the reactivity of the complexes. Thus [(Me-Duphos) (1,3-diphenylallyl)palladium] chloride leads mostly to [(Me-Duphos)dichloropalladium] and to chalcone at room temperature, whereas at low temperature a pair of cationic and anionic allyl palladium complexes is obtained. (C) 2002 Academie des sciences / Editions scientifiques et medicales Elsevier SAS.