Ultrastable two-dimensional fluorescent conjugated microporous polymers containing pyrene and fluorene units for metal ion sensing and energy storage

This study aims to synthesize three conjugated microporous polymers (CMPs) [Py-F CMP, TPE-F CMP, and TBN-F CMP] via the Suzuki coupling reaction of 9,9-dihexylfluorene-2,7-diboronic acid [F-B(OH)2] with three bromi-nated derivatives, pyrene (Py), tetraphenylethylene (TPE), and tetrabenzonaphthalene (TBN). The functional groups and chemical structures of the three synthesized CMPs were confirmed using FTIR and solid-state NMR analyses. Thermogravimetric analysis (TGA) revealed that TBN-F CMP has the most outstanding Td10 = 418 degrees C and char yield = 63.3 wt% compared to the other two samples. The BET surface area and average pore size of TBN-F CMP were measured to be 200 m2 g-1 and ca. 1.8 nm, respectively. Furthermore, with excellent pho-toluminescence (PL) properties, all three new CMPs were well characterized using a spectrophotometer, and the fluorescence emission spectra were clearly drawn. As a result, we found that Py-F CMP can detect Pb2+ ions specifically and selectively compared to the other two CMPs. The sensitivity of Pb2+ was calculated and fitted with linear coefficients (R2 = 0.9752) to determine the Pb2+ ion concentration over the ranges of 0.1-2.0 mu M, and the detection limit was estimated to be 0.01 mu M. Finally, with outstanding capacitance and stability of up to 195 F g-1 and 90% over 2000 cycles, TBN-F-based CMP has been successfully applied to electrochemical measurements.

Automated summary

This study synthesized three conjugated microporous polymers (CMPs) via Suzuki coupling reaction and characterized their functional groups and chemical structures using FTIR and solid-state NMR analyses. Among the three CMPs, TBN-F CMP showed the highest thermal stability and excellent capacitance and stability for electrochemical measurements. Py-F CMP exhibited specific and selective detection of Pb2+ ions. The findings suggest the potential applications of these CMPs in various fields.