Triarylboron-Linked Conjugated Microporous Polymers: Sensing and Removal of Fluoride Ions

• Published in: Chemistry : a European journal 2015-11, Vol.21 (48), p.17355-17362
• Main Authors: Li, Zhongping, Li, He, Xia, Hong, Ding, Xuesong, Luo, Xiaolong, Liu, Xiaoming, Mu, Ying
• Format: Article
• Language: English
• Subjects: Adsorbents; Adsorption; Buildings; Carbon; Chemical reactions; Chemistry; chemosensors; Fluorescence; fluoride removal; fluoride sensing; Fluorides; luminescence; Polymers; Spectrum analysis; Surface chemistry
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201502241

A luminescent conjugated microporous polymer (BCMP‐3) has been synthesized in high yield by a carbon–carbon coupling reaction using triarylboron as a building unit. BCMP‐3 was fully characterized by using powder X‐ray diffraction analysis, Fourier transform infrared spectroscopy, 13C solid‐state NMR spectroscopy, field emission scanning electron microscopy, thermogravimetric analysis, and nitrogen and carbon dioxide adsorption. The new three‐dimensional conjugated framework possess a high Brunauer–Emmett–Teller (BET) specific surface area up to 950 m2 g−1 with a pore volume of 0.768 cm3 g−1, good stability, and abundant boron sites in the skeleton. Under excited‐light irradiation, BCMP‐3 exhibits strong fluorescent emission at 488 nm with a high absolute quantum yield of 18 % in the solid state. Polymer BCMP‐3 acts as a colorimetric and fluorescent chemosensor with high sensitivity and selectivity for F− over other common anions. In addition, the polymer also works as an adsorbent for F− removal and shows good adsorption capacities of up to 24 mg g−1 at equilibrium F− concentrations of 16 mg L−1 and a temperature of 298 K. The adsorption kinetics and isotherm were analyzed by fitting experimental data with pseudo‐second‐order kinetics and Langmuir equations. Furthermore, we highlight that BCMP‐3 is an adsorbent for fluoride removal that can be efficiently reused many times without loss of adsorption efficiency. A luminescent conjugated microporous polymer is constructed by a carbon–carbon coupling reaction using triarylboron as a building unit. The polymer possesses a high surface area and exhibits high sensitivity and selectivity for fluoride anions. It can also act as a new kind of adsorbent with good adsorption capacities and excellent reusability for fluoride removal (see scheme).