A convenient method for the generation of {Rh(PNP)}+ and {Rh(PONOP)}+ fragments: reversible formation of vinylidene derivatives

Abstract

The substitution reactions of [Rh(COD)₂][BAr^F₄] with PNP and PONOP pincer ligands 2,6-bis(di-tert-butylphosphinomethyl)pyridine and 2,6-bis(di-tert-butylphosphinito)pyridine in the weakly coordinating solvent 1,2-F₂C₆H₄ are shown to be an operationally simple method for the generation of reactive formally 14 VE rhodium(I) adducts in solution. Application of this methodology enables synthesis of known adducts of CO, N₂, H₂, previously unknown water complexes, and novel vinylidene derivatives [Rh(pincer)(CCHR)][BAr^F₄] (R = tBu, 3,5-tBu₂C₆H₃), through reversible reactions with terminal alkynes.