A Dual Colorimetric/Fluorescence System for Determining pH Based on the Nucleophilic Addition Reaction of an o‐Hydroxymerocyanine Dye |
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| Authors: | Yongkang Yue Fangjun Huo Songyi Lee Prof Caixia Yin Prof Juyoung Yoon Prof Jianbin Chao Prof Yongbin Zhang Prof Fangqin Cheng |
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| Institution: | 1. Institute of Molecular Science, Shanxi University, Taiyuan, P. R. China;2. Research Institute of Applied Chemistry, Shanxi University, Taiyuan, P. R. China;3. Department of Chemistry, University of Missouri, Columbia, Missouri, USA;4. Department of Chemistry and Nano Science, Ewha Womans University, Seoul, Korea |
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| Abstract: | Owing to their ability to monitor pH in a precise and rapid manner, optical probes have widely been developed for biological and nonbiological applications. The strategies thus far employed to determine pH rely on two types of processes including reversible protonation of amine nitrogen atoms and deprotonation of phenols. We have developed a novel dual, colorimetric/fluorescence system for determining the pH of a solution. This system utilizes an o‐hydroxymerocyanine dye that undergoes a nucleophilic addition reaction that subsequently causes reversible structural changes interconverting a merocyanine to a spirocyanine and a spirocyanine to a spiropyran. It was demonstrated that the dye can be employed to measure the pH of solutions in the 2.5–5.75 and 9.6–11.8 ranges with color changes from yellow to dark blue and then to lavender. Moreover, the fluorescence response associated with the spirocyanine–spiropyran transformation of the dye occurring in alkaline solutions provides a precise method. |
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| Keywords: | colorimetric probe cyanine fluorescent probe nucleophilic addition pH sensors |
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