Structural NMR studies on aryl-substituted π-allyl-Pd(II) complexes by concerted use of gradient-based experiments

Complete 1H and 13C NMR assignments of several aryl-substituted π-allyl-Pd(II) complexes were achieved using modern gradient-based 1D and 2D experiments. In addition, unambiguous 31P assignments were readily made using an improved gradient-enhanced 1H-31P HMBC experiment from which the regiochemistry of cationic complexes containing asymmetric bidentate ligands could also be elucidated. The effect of the nature of the substituent on allylic proton and carbon chemical shifts is briefly evaluated. Finally, a partial π-σ-π isomerization mechanism is proposed taking into account some observed dynamic NMR processes which are largely dependent on the ligand nature of these complexes. © 1997 by John Wiley & Sons, Ltd.