Protonation of 1,8-bis(dimethylamino)naphthalene by N–H proton donors in acetonitrile

Abstract

FTIR studies were carried out on a number of systems composed of 1,8-bis(dimethylamino)naphthalene (DMAN) and various N–H proton donors in acetonitrile. The degree of protonation was estimated based on the intensity of the Bohlmann bands. As in the case of systems containing OH acids homoconjugated anions play an important role in ionic equilibria. In the case of moderately strong proton donors the species present in solution are protonated DMAN, free DMAN, NHN^– homoconjugated anions and more complicated self-solvated species. The homoconjugated NHN^– anions are characterized by a broad doublet with submaxima at ca. 1950 and 2500 cm^–1.