Synthesis, crystal structure, and spectra of bis(3,3-dimethyl-3,4-dihydroisocarbostyril)azinium nitrate

Bis(3,3-dimethyl-3,4-dihydroisocarbostyril)azinium nitrate (HL)NO3 (I) is synthesized, and its crystal structure is determined. It is shown that protonation of L proceeds at one of the exocyclic nitrogen atoms. The tautomeric form of the HL+ cation in I is intermediate between the azine and hydrazine tautometric forms. The structure of I is studied by IR and electronic absorption spectroscopies.