New Fast, Highly Selective Probe with Both Aggregation-Induced Emission Enhancement and Intramolecular Charge-Transfer Characteristics for Homocysteine Detection

A new fluorescence probe 2-(4′-(diphenylamino)-[1,1-biphenyl]-4-yl)-2<i>H</i>-[1,2,3]-triazole-4-carbaldehyde (DBTC) was designed and synthesized through Suzuki coupling reaction between (4-(diphenylamino)­phenyl)­boronic acid and (4-bromophenyl)-2<i>H</i>-[1,2,3]-triazole-4-carbaldehyde. This probe DBTC had intramolecular charge transfer and aggregation-induced emission enhancement performances and showed high selectivity and sensitivity toward homocysteine (Hcy) in the presence of other amino acids. The detection limit of probe DBTC for Hcy was 3.05 × 10<sup>–6</sup> M, and the mechanism was researched by <sup>1</sup>H NMR titration experiments and mass spectrometry. Furthermore, cell-culture results indicated that probe DBTC was cell permeable and could be used to detect Hcy in living cells. The good characteristics of the probe DBTC had huge application potential use for researching the effects of Hcy in other biological systems.