Effects of chelate ligands containing NN, PN, and PP on the reactivity of organoplatinum(II) complexes in oxidative addition reactions

Three d8 square-planar complexes of the type [PtMe2(LL)], [LL = 2,2′-bipyridine (NN), 2-(2-pyridyl)phosphinine (PN) and 2,2′-biphosphinine (PP)], with a systematic variation in the chelating ligands, have been chosen for investigating their SN2-type oxidative addition reactions with MeI by means of DFT calculations with the B3LYP functional. The oxidative addition proceeded via a transition state with a nearly linear arrangement of the I–CH3–Pt moiety. It was found that the addition of MeI is exothermic for all three chelate rings, and [PtMe2(NN)] is predicted to react with a much lower barrier than either [PtMe2(PN)] or [PtMe2(PP)]. In agreement with the available experimental data, the DFT results suggest that the MeI oxidative addition is more favorable with the complex bearing the 2,2′-bipyridine ligand as compared to the other chelate rings, 2-(2-pyridyl)phosphinine (PN) or 2,2′-biphosphinine (PP).

Graphical abstractThe oxidative addition reactions of three platinum square planar complexes of the type [PtMe2(LL)] (LL = NN, PN, PP) with MeI, with a systematic variation in the chelate ligands, have been theoretically investigated.Figure optionsDownload full-size imageDownload as PowerPoint slide