Reductive Elimination of C₆F₅–C₆F₅ from Pd(II) Complexes: Influence of α-Dicationic Chelating Phosphines

We report the synthesis and characterization through NMR and X-ray techniques of a series of [Pd(C 6 F 5 ) 2 (P ∧ P′)] complexes constituted by diphosphine chelating ligands of different nature and evaluate the rates for the challenging reductive elimination of C 6 F 5 –C 6 F 5 . By virtue of their very weak donor properties, dicationic ancillary ligands effectively promote the desired transformation. Density functional theory (DFT) calculations were performed to rationalize these findings. The Pd(0)-complexes formed after the elimination step could not be isolated because the Pd(0) center has a tremendous tendency to insert into one of the P–C + bonds of the α-cationic ligands rendering Pd(II)-phosphinidene complexes. The same behavior was observed for Ni(0) species.