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

A tert -butyldiphenylsilyl-containing polyimide ( PI-OSi ) has been established as a colorimetric and ratiometric chemosensor for rapid detecting fluoride ions (F - ). The UV-vis absorbance ratio value (A 322 /A 288 ) of PI-OSi 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 PI-OSi shows an immediate color change to yellow and finally to green from colorless. More interestingly, the resulting PI-OSi plus F - system ( PI-OSi ·F) could detect trace water in DMF. The A 292 /A 322 value of PI-OSi ·F almost linearly increases with low water content, which suggests convenient quantitative sensing of trace water content in DMF. The DL value of PI-OSi ·F for sensing water in DMF is determined to be 0.00149% ( v / v ). The solution color of PI-OSi ·F returns to colorless when the water content increases, indicating that PI-OSi ·F can conveniently estimate water content in DMF by naked-eye detection. The detection mechanisms confirmed by an 1 H NMR study and a DFT calculation involve a F - -induced desilylation reaction of PI-OSi to form phenolate anion followed by protonation with trace water. Finally, PI-OSi film was fabricated for the colorimetric detection of F - and water in CH 3 CN.