Fluorocarbene, fluoroolefin, and fluorocarbyne complexes of Rh

Abstract

The manuscript reports the synthesis, characterization, and analysis of electronic structure in a series of complexes of small perfluorocarbon ligands with the (PNP)Rh fragment (where PNP is a diarylamido/bis(phosphine) pincer ligand). Reactions of (PNP)Rh(TBE) as the source of (PNP)Rh with CHF₃ and C₂HF₅ produced perfluoroalkylidene complexes (PNP)RhCF₂ and (PNP)RhC(F)(CF₃). (PNP)RhCF₂ could also be obtained via the reaction of (PNP)Rh(TBE) with Me₃SiCF₃/CsF, with an admixture of (PNP)Rh(C₂F₄), where TBE = tert-butylethylene. Abstraction of fluoride from these neutral (PNP)RhC_xF_y complexes was successful, although only abstraction from (PNP)RhCF₂ allowed unambiguous identification of the Rh product, [(PNP)RhCF]⁺. DFT computational studies allowed comparison of relative energies of (PNP)Rh(C₂F₄) and [(PNP)Rh(C₂F₃)]⁺ isomers as well as comparisons between the electronic structure of the CF₂, C₂F₄, and CF⁺ complexes and their hydrocarbon analogues.