Tunable thiophene-based conjugated microporous polymers for the disposal of toxic hexavalent chromium

Herein we report the rational syntheses of three conjugated microporous polymers (CMPs) through one-pot polycondensation coupling of a boronated triphenylpyridine (TPP-3Bor) with 4,7-bis(5-bromothien-2-yl)benzo[c][1,2,5]thiadiazole (ThZ-2Br), 2,5-dibromothiophene (Th-2Br), and 1,4-dibromobenzene (Bz-2Br), yielding the TPP-ThZ, TPP-Th, and TPP-Bz CMPs, respectively, featuring different thiophene contents, topologies, and molecular structures. Various characterization techniques are used to investigate the structural properties of these TPP-based CMPs, revealing their spherical morphologies, tunable pore volumes, and high thermal and chemical stabilities. We test the TPP-based CMPs for their use in the dynamic adsorptive reduction of toxic Cr(vi) ions. Among them, the TPP-ThZ CMP possesses the highest adsorption capacity for Cr(vi) (209 mg g⁻¹); this performance is also higher than those of other recently reported adsorbents. Furthermore, our TPP-based CMPs exhibit good reusability for the reduction and adsorption of Cr(vi) ions. Accordingly, these novel thiophene-based CMPs not only function as dynamic materials for the reduction-adsorption of Cr(vi) but also reveal the potential of thiophene linkers in the future design of such Cr(vi) adsorbents.