Yan-Cheng Wu, Jiajian You, Kai Jiang
Feb 1, 2018
Citations
0
Influential Citations
29
Citations
Journal
Dyes and Pigments
Abstract
Abstract 2,6-Bis(1-alkyl-1 H -benzo[ d ]imidazol-2-yl)naphthalene ( 2a - 2c ) as three new benzimidazole molecules have been designed, synthesized and applied as ratiometric fluorescent pH probes in the acidic pH region with high-efficiency and fast response. For probe 2a , upon decreasing the pH from 7.5 to 2.5, the emission spectra exhibit a large red shift from 402 to 472 nm, and the emission ratio (I 472 /I 402 ) changes dramatically from 0.10 to 3.42 with a p K a value of 2.92. No significant interference on emission behavior is observed in the presence of various metal ions. Similar results are obtained for probes 2b and 2c . 1 H NMR and DFT calculations studies demonstrate that the ratiometric response of the probes to acidic pH is due to H + binding with one N atom in C=N of benzimidazole ring and the subsequent enhancement of the intramolecular charger transfer (ICT) process. In addition, these probes can be used in real-time and reversible pH sensing. Finally, the probes have been successfully applied to the visual detection of pH not only in solution, but also in test paper.