Room-temperature long-lived [Nb2F11]− salts of radical cations of simple arenes: EPR, UV-Vis and DFT results

► The [Nb2F11]− ion provides great inertness to radical cations of monocyclic arenes. ► The inertness increases on decreasing the steric hidrance of the ring substituents. ► EPR spectra of the salts evidence coupling with the anion nuclei. ► UV-Vis spectra show a anion-to-cation charge-transfer band. ► The benzene salt is obtained in low yield for thermodynamic reasons.