Simple and hydrolytically stable proton sponge based organic cation displaying hydrogen bonding and a number of related phenomena

It has been shown that 8-dimethylamino-1-dimethylammonio-5-nitronaphthalene is an organic cation capable of displaying such fundamental phenomena as hydrogen bonding, conjugation, acid–base equilibrium, dissociation, and thermo- and solvatochromism. Even in neutral (N-deprotonated) form, this compound may function as a solvatochromic probe to distinguish between acidic solvents (carboxylic acids). Other possible fields of application are also discussed along with the experimental comparison with some related proton sponge molecules.