Design, Synthesis, and Aggregation-Induced Emission Properties of a Novel D−π–A Conjugated Molecule as a Selective Hydrazine Sensor

In this study, a new D-π-A type conjugated molecule containing <i>N,N</i>-dimethyl donor group and cyanostilbene and dicyanovinyl acceptor groups was designed and synthesized. The molecule exhibited aggregation-induced emission (AIE) property in chloroform-hexane medium; the structure, which gave low fluorescence in solution, showed intense fluorescence under low polarity conditions. In addition, it was observed that the molecule responded selectively and sensitively only to hydrazine compared to various amine compounds (TEA, DEA, aniline, ammonia), thanks to its dicyanovinyl group. A significant hypsochromic shift occurred in the spectrum in the presence of hydrazine, and an increase in fluorescence intensity was observed along with a color change. Furthermore, tests on thin-layer chromatography (TLC) determined that the molecule showed a rapid and visually observable interaction with hydrazine. These results reveal that the designed molecule can be used both in solid-state AIE-enabled optoelectronic applications and as a hydrazine-selective chemical sensor.