Protonation of N2O and NO2 in a solid phase

Adsorption of gaseous N2O on the acidic surface Bronsted centers of the strongest known solid acid, H(CHB11F11), results in formation of the N N-OH+ cation. Its positive charge is localized mainly to the H-atom, which is H-bonded to the CHB11F11- anion forming an asymmetric proton disolvate of the L-1-H+center dot center dot center dot L-2 type, where L-1 = N2O and L-2 = CHB11F11-. NO2 protonation under the same conditions leads to the formation of the highly reactive cation radical NO2H center dot+, which reacts rapidly with an NO2 molecule according to the equation N2OH+ + NO2 --> [N2O4H+] --> N2OH+ + O-2 resulting in the formation of two types of N2OH+ cations: (i) a typical Bronsted superacid, N N-OH+, with a strongly acidic OH group involved in a rather strong H-bond with the anion, and (ii) a typical strong Lewis acid, N N+-OH, with a positive charge localized to the central N atom and ionic interactions with the surrounding anions via the charged central N atom.