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)Rh═CF2 and (PNP)Rh═C(F)(CF3). (PNP)Rh═CF2 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)RhCxFy complexes was successful, although only abstraction from (PNP)Rh═CF2 allowed unambiguous identification of the Rh product, [(PNP)Rh=CF]+. 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.