Pd-(MOP) chemistry: Novel bonding modes and interesting charge distribution

The new Pd-MOP acetyl acetonate complexes [Pd(acac)(10a or 10b)]BF4, 12a,b, were prepared starting from [Pd(acac)(CH3CN)(2)]BF4, whereas [Pd(acac)(11-H)], 13, was obtained directly from Pd(acac)(2) by adding 11. [Ligand 10a, MeO-MOP = (R)-2-(diphenylphosphino)-2'-methoxy-1,1'-binaphthyl; ligand 11, HO-MOP = (R)-2-(diphenylphosphino)-2'-hydroxy-1,1'-binaphthyl]. The solid-state structures for cationic 12a and neutral 13 were determined via X-ray diffraction methods and reveal that both structures contain Pd-C sigma-bonds arising from the MOP naphthyl backbone. In structure 13, the hydroxyl function in 11 has lost a proton to afford a keto-anionic chelating ligand. C-13 NMR studies confirm that the solution structures are the same as those found in the solid state and, for 12, describe how the organic cation distributes the positive charge.