A -Butyldiphenylsilyl-Containing Polyimide-Based Chemosensor for Sequential Detection of Fluoride Ions and Trace Water in Organic Solvents.

A -butyldiphenylsilyl-containing polyimide () has been established as a colorimetric and ratiometric chemosensor for rapid detecting fluoride ions (F). The UV-vis absorbance ratio value (A/A) of in a DMF solution displays a wide linear range change to F concentrations with a detection limit (DL) value of 2.13 μM. Additionally, adding incremental amounts of F to a DMF solution of shows an immediate color change to yellow and finally to green from colorless. More interestingly, the resulting plus F system (·F) could detect trace water in DMF. The A/A value of ·F almost linearly increases with low water content, which suggests convenient quantitative sensing of trace water content in DMF. The DL value of ·F for sensing water in DMF is determined to be 0.00149% (/). The solution color of ·F returns to colorless when the water content increases, indicating that ·F can conveniently estimate water content in DMF by naked-eye detection. The detection mechanisms confirmed by an H NMR study and a DFT calculation involve a F-induced desilylation reaction of to form phenolate anion followed by protonation with trace water. Finally, film was fabricated for the colorimetric detection of F and water in CHCN.