Rhodium(I) Complexes with a η¹-Fluorenyl-P-phosphanylphosphorane Ligand

Abstract

The first example of a P-phosphanylphosphorane, Flu═PCy₂-PCy₂ (L2; Flu = 9-fluorenyl), has been easily prepared by P-phosphination of lithiated 9-dicyclohexylphosphinofluorene (FluPCy₂, L0) with chlorodicyclohexylphosphane. L2 constitutes a new type of P(III)-P(V) organophosphorus compound, a σ³λ³-σ⁴λ⁵ species that is stable under an inert atmosphere in the solid state. The reaction of L2 with [Rh(diene)₂]BR₄ causes metalation of the benzylic carbon (C9) of fluorene, giving κ²-C,P complexes in which fluorene is coordinated in the η¹ form. A complex with the weakly coordinating BArF anion has been isolated and fully characterized, including its crystal structure obtained by X-ray diffraction.