Solvatoemissive dual fluorescence of N-(pyridylmethyl)-3-nitro-1,8-naphthalimides.

Solvatoemissive dual fluorescence emission observed in the three positional isomers of N-(n-pyridylmethyl)-3-nitro-1,8-naphthalimide [n = 2 (1), 3 (2), 4 (3)] are described. Dual fluorescence emission in this class of compounds occurs from the excited states with extended conjugation via π-stacking interactions. The crystal structure of the compound 1 and the chloride salt of 2 were determined. The compound 1 forms dimeric assemblies through π-stacking interactions. Whereas the structure of the chloride salt of 2 is composed of dimeric assemblies of the cationic part which hold cyclic hydrated anionic assemblies through weak C-H(…)Cl interactions. Anionic hydrated assemblies between water and chloride ions have cyclic tetrameric structure through O-H(…)Cl interactions.