Reactions of Doubly Ionized Benzene with Nitrogen and Water: A Nitrogen-Mediated Entry into Superacid Chemistry
Abstrakt
Even in the highly diluted gas phase, rather than electron transfer the benzene dication C6H6(2+) undergoes association with dinitrogen to form a transient C6H6N2(2+) dication which is best described as a ring-protonated phenyl diazonium ion. Isotopic labeling studies, photoionization experiments using synchrotron radiation, and quantum chemical computations fully support the formation of protonated diazonium, which is in turn a prototype species of superacidic chemistry in solution.
Additionally, reactions of C6H6(2+) with background water involve the transient formation of diprotonated phenol and, among other things, afford a long-lived C6H6OH2(2+) dication, which is attributed to the hydration product of Hogeveens elusive pyramidal structure of C6H6(2+), as the global minimum of doubly ionized benzene. Nitrogen is essential for the formation of the C6H6OH2(2+) dication in that it mediates the formation of the water adduct, while the bimolecular encounter of the C6H6(2+) dication with water only leads to (dissociative) electron transfer.