Changing π‑Interactions and Conformational Adjustments of <i>N</i>‑(Isonicotinylhydrazide)-1,8-naphthalimide by Hydration and Complexation Affect Photophysical Properties

Noncovalent self-assemblies of different forms of a 1,8-naphthalimide derivative <i>N</i>-(isonicotinylhydrazide)-1,8-naphthalimide adopt different conformational adjustments due to the interplay of weak interactions. In such assemblies stacking interactions significantly contribute to direct the orientations of tether, which also influenced packing patterns. Effects of weak noncovalent interactions are reflected in the physicochemical properties of solvate and metal complexes of this naphthalimide derivative. Dual fluorescence emissions were observed from hydrate and silver complex of <i>N</i>-(isonicotinylhydrazide)-1,8-naphthalimide, which was not observed in anhydrous form of the compound. These results are compared with fluorescence emission study performed with solution of <i>N</i>-(isonicotinylhydrazide)-1,8-naphthalimide. Aggregation induced fluorescence emission of a solution in DMSO was caused by adding water. This emission in solution occurred at a much different emission wavelength than the emission observed from the hydrated sample in the solid state. It is also established that the aggregation induced fluorescence of <i>N</i>-(isonicotinylhydrazide)-1,8-naphthalimide caused by adding water to a solution of the compound in dimethyl sulfoxide can be quenched by different nitro-phenols