Fluorene-based polymers of intrinsic microporosity as fluorescent probes for metal ions

A portable fluorescent probe with quick response for sensing metal ions is of great demand. Here, for the first time, a novel fluorene-based polymer of intrinsic microporosity (PIM), PFLTB, was synthesized through Tröger's base reaction, which exhibits a fluorescent response for Fe 3+ with high selectivity, sensitivity and rapidity. The PFLTB possesses M n of 12,050 g mol −1 , specific surface area of 453 m 2 g −1 , and high intrinsic fluorescence at 470 nm excited by 310 nm. It is found that the fluorescent quenching of PFLTB against Fe 3+ is particularly notable as compared to other metal ions. The selectivity of PFLTB for Fe 3+ was also determined by the interference experiment, and the limit of detection of PFLTB towards Fe 3+ was measured to be 5.04 μmol L −1 . PFLTB-based indicator film was fabricated by coating onto polyphenylene sulfide (PPS) porous non-woven, which showed the fast fluorescence quenching against Fe 3+ with a response time of only 10 s. Our work offers a novel and feasible approach to fabricate efficient polymer-based sensors for metal ions, which is of great importance for diverse industrial and engineering processes. • A novel fluorene-based polymer of intrinsic microporosity (PFLTB) was prepared for the first time. • The PFLTB possesses moderate specific surface area and high intrinsic fluorescence. • The PFLTB shows a fluorescent response for Fe 3+ with high selectivity, sensitivity and rapidity. • PFLTB-based indicator film shows the fast fluorescence quenching towards Fe 3+ .