Characterization of the aggregation-induced enhanced emission, sensing, and logic gate behavior of 2-(1-hydroxy-2-naphthyl)methylene hydrazone

2-(1-Hydroxy-2-naphthyl)methylene hydrazone (HMNH), with two naphthalene planar conjugated moieties linked by a rotatable NN single bond, has been feasibly synthesized. This molecule is characterized by aggregation-induced emission enhancement properties, exhibiting markedly enhanced fluorescence after aggregation in DMF (N,N-dimethylformamide)/H2O mixed solvent. According to spectroscopic data, crystal structure determination, SEM, and fluorescence microscopy, rotation round the intramolecular single bond is hindered by the combined effects of intramolecular hydrogen-bond formation and ordered molecular stacking with aggregate formation, which inhibit non-radiative transitions in the aggregated state. HMNH has excellent metal ion recognition properties, isolated HMNH working as a fluorescence turn-on sensor for Zn2+, but aggregated HMNH with AIEE as a turn-off sensor for Co2+. Using OH− and Zn2+/Co2+ as chemical inputs and the fluorescence signal as output, AND and NAND logic gates operating at the molecular level have been constructed. This single molecule sensor for multiple analytes by isolated or aggregated is promising and has been rarely exploited.