π-Conjugated polycarbazole–boron complex as a colorimetric fluoride ion sensor

Fluoride anion sensors are of paramount interest, because of the utility of this anion in spite of its high toxicity. Detection and quantification of fluoride ion become vital for their application in the field of medicine. Search for new materials and sensors have never ceased owing to the drawbacks such as cumbersome procedures involved in the synthesis of material or the difficulty in monitoring the sensitivity of the material. Hence, the present research was prompted in the lookout for a new material with a facile method coupled with a simple detection procedure. Herein, we report a new type of fluoride anion responsive π-conjugated polymer, a polycarbazole–BF3 complex. The polymer was facilely prepared by adding an equimolar amount of boron trifluoride–diethyl ether complex to a THF solution of polycarbazole at room temperature. The polycarbazole–BF3 complex was confirmed for its structure using 1H NMR and 11B NMR. The synthesized polymer was tested for their F− ion sensitivity, which showed significant visual color change with a change in F− ion concentration facilitating a high degree of ease in its application.