1,1,1,3,3,3-Hexafluoropropan-2-ol as a solvent for the generation of highly persistent radical cations

1,1,1,3,3,3-Hexafluoropropan-2-ol (HFP) has been found to be a superior solvent for the generation of radical cations, in many cases increasing their half-lives by a factor of 102 compared with those pertaining to trifluoroacetic acid. This study has mainly used 4-tolylthallium(III) bis(trifluoroacetate) and thallium(III) tris(trifluoroacetate) as oxidants, but DDQ could also be employed in the presence of 5% trifluoroacetic acid. Photochemical oxidation by mercury(II) bis(trifluoroacetate) also worked well. Thus room temperature recording of high quality EPR spectra of radical cations previously accessible only by flow or low-temperature procedures has become feasible.