A π‐Conjugated Chromophore Dye and Its Functional Paper Strips for Visually On‐Site Sensing F⁻ and Its Reaction Mechanism

Abstract

An improved D−A‐D typed π‐conjugated optical chromophore (PBHPI) with multi‐activated recognition sites and its functionalized testing‐paper strips were constructed and developed, for the first time, based on B3LYP/6‐31G level of theory in Gaussian 03 suite. After its UV‐vis spectral property was investigated in detail, it was noted to find that the target PBHPI and its functionalized paper strips could conclusively react with F− with obvious color change from light yellow to dark red. Under the optimized experimental conditions, both PBHPI and its functionalized paper‐strips could selectively recognize F− with a double‐wavelength colorimetric response to realize a wide linear range from 5.0 ×10–6 mol/L to 1.4 ×10–4 mol/L. The present sensing systems were successfully applied for visually on‐site monitoring F− in some commercial organic and toothpaste samples simply and conveniently. The recognition mechanism was confirmed to be the deprotonating mechanism to form multiple hydrogen bonds as what we expected.

Photooxidation of IR‐820 by Calixpyridinium‐Induced Assembled Material and Its pH‐Controlled Visual Multicolor Luminescence

“…[ 46 ] Herein, third, benefitting from the pH‐dependent luminescent properties of calixpyridinium and the photodegradation products of IR‐820, a pH‐controlled multicolor luminescence was achieved. The highly sensitive and selective detection of pH is extremely important because pH plays an important role in various physiological, chemical and physical processes, such as tumor growth, [ 47‐49 ] ion transport, [ 50‐51 ] catalytic reaction, [ 52‐53 ] and energetic conversion. [ 54‐56 ] The above mentioned pH‐controlled multicolor luminescence could be perfectly applied in the detection of pH from 5 to 10 by naked eyes.…”

A Dual‐Mode Colorimetric/Fluorescent Sensor Comprising Rhodamine B and Piperazine: Response to Acidic pH Values and Investigation of Recognition Mechanism

“…As we all know that pH plays an important role in various physical, chemical and physiological processes, such as catalytic reaction, hydrolyzed reaction, enzymatic activity, ion transport, tumor growth and energetic conversion . Too high or too low pH will deviate the normal direction in natural environments.…”