Rapid interconversion of diastereomers of [PdCl{P(OC6H4NMe)2}{P(OC6H4NMe)OC6H4NHMe}]

The palladium(II) complex [PdCl{P(OC6H4NMe)2}{P(OC6H4NMe)OC6H4NHMe}] undergoes rapid interconversion between diastereomers by inversion of a displaced amine ligand. [Display omitted] •A Pd(II) complex with a hydrophosphorane coordinated in both P(V) and P(III) forms.•A crystal structure of the Pd(II) complex was obtained.•The Pd(II) complex is comprised of 4 different diastereomers (each a pair of enantiomers), which are identified by 31P{1H} and 1H NMR.•At room temperature, there is rapid interconversion between pairs of diastereomers and the various possible mechanisms for this are investigated, using variable temperature 31P{1H} NMR and DFT studies.•The proposed mechanism of interconversion is the inversion of a dissociated amine ligand. [PdCl{P(OC6H4NMe)2}{P(OC6H4NMe)OC6H4NHMe}] was prepared by the reaction of LiP(OC6H4N(CH3))2 with [PdCl2{P(OC6H4N(CH3))(OC6H4NH(CH3))}]. The expected four diastereomers of the complex are observed in the 31P{1H} and 1H NMR at −20 °C, however at room temperature there is fast exchange between pairs of diastereomers. The energetics of three possible mechanisms by which the diastereomers may be interconverting, are considered by DFT studies: displacement of the coordinated amine, followed by inversion at the nitrogen atom; displacement of the coordinated phosphoramidite, followed by inversion at the phosphorus atom; Berry pseudorotation at the coordinated phosphoranide. The inversion of a dissociated amine appears to be the most likely mechanism.