title: A Dual Colorimetric/Fluorescence System for Determining pH Based on the Nucleophilic Addition Reaction of an o-Hydroxymerocyanine Dye.
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.
authors.affiliation: Institute of Molecular Science, Shanxi University, Taiyuan, 030-006, P. R. China.
authors.forename: Yongkang
authors.initials: Y
authors.lastname: Yue
authors.affiliation: Research Institute of Applied Chemistry, Shanxi University, Taiyuan, 030-006, P. R. China.|Department of Chemistry, University of Missouri, 601 South college Avenue, Columbia, Missouri, 65211, USA.
authors.forename: Fangjun
authors.initials: F
authors.lastname: Huo
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 120-750, Korea.
authors.forename: Songyi
authors.initials: S
authors.lastname: Lee
authors.affiliation: Institute of Molecular Science, Shanxi University, Taiyuan, 030-006, P. R. China. yincx@sxu.edu.cn.|Department of Chemistry, University of Missouri, 601 South college Avenue, Columbia, Missouri, 65211, USA. yincx@sxu.edu.cn.
authors.forename: Caixia
authors.initials: C
authors.lastname: Yin
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 120-750, Korea. jyoon@ewha.ac.kr.
authors.forename: Juyoung
authors.initials: J
authors.lastname: Yoon
authors.affiliation: Research Institute of Applied Chemistry, Shanxi University, Taiyuan, 030-006, P. R. China.
authors.forename: Jianbin
authors.initials: J
authors.lastname: Chao
authors.affiliation: Research Institute of Applied Chemistry, Shanxi University, Taiyuan, 030-006, P. R. China.
authors.forename: Yongbin
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Institute of Molecular Science, Shanxi University, Taiyuan, 030-006, P. R. China. cfangqin@sxu.edu.cn.
authors.forename: Fangqin
authors.initials: F
authors.lastname: Cheng
keywords: colorimetric probe; cyanine; fluorescent probe; nucleophilic addition; pH sensors