A novel pH probe based on ratiometric fluorescent properties of dicyanomethylene-4H-chromene platform

• Published in: Talanta (Oxford) Vol. 174; pp. 59 - 63
• Main Authors: Liu, Xiaolei, Han, Jixun, Zhang, Yan, Yang, Xiaofeng, Cui, Yu, Sun, Guoxin
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.11.2017
• Subjects: Dicyanomethylene-4H-chromene; Ratiometric probe; Remarkable Stokes shift; Reusable; pH; Ratiometric probe; Remarkable Stokes shift; Dicyanomethylene-4H-chromene; Reusable
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2017.05.034

We report here a ratiometric pH probe (Z)−2-(2-(2-(4-hydroxyphenyl)−2-(pyrrolidin-1-yl)vinyl) −4H-chromen-4-ylidene)-malononitrile over the pH range of 2.44–6.00. It was synthesized by Knoevenagel Reaction from dicyanomethylene-4H-chromene and pyrrolidine. This is the first example of pyrrolidine as a part of the product structure in Knoevenagel condensation. High selectivity and sensitivity for pH variation were observed with significant fluorescent ratiometric responses and a remarkable Stokes shift (about 138nm). The probe was stable in the studied solvent and no obvious fluorescence changes were detected in acidic media within one month at room temperature. [Display omitted] •We synthesized a ratiometric pH probe base on dicyanomethylene-4H-chromene..•We firstly reported pyrrolidine had a dual roles in this Knoevenagel condensation.•This probe showed high selectivity and sensitivity for pH variation (pH=2.44–6.00).•The probe was stable in the studied solvent within one month at room temperature.