Carbazolic Porous Framework with Tetrahedral Core for Gas Uptake and Tandem Detection of Iodide and Mercury

A multifunctional carbazolic porous framework (Cz-TPM), with a tetrahedral core, has been synthesized by FeCl3 oxidative coupling polymerization. The Brunauer–Emmett–Teller surface area of the obtained polymers reaches 713.2 m2 g–1. Gas adsorption isotherms show that Cz-TPM exhibits large carbon dioxide (97.9 mg g‑1, 9.8 wt %, 273 K, and 1 bar) and hydrogen uptake capacities (149.3 cm3 g‑1, 1.34 wt %, 77 K, and 1 bar). Furthermore, Cz-TPM has been found to display tandem visual detection of iodide and mercury, respectively. The Cz-TPM dispersion turns to yellow in the presence of iodide salts and subsequently changes to nearly colorless on addition of Hg2+ salts that could be easily observed by the naked eye. Cz-TPM can detect I– via “turn off” fluorescence quenching, and then the in situ generated Cz-TPM@I complexes can recognize Hg2+ ions via “turn on” fluorescence recovery. More importantly, Cz-TPM is stable over common solvents and can be easily recovered by excessive water washing and centrifugation for further repeated use. As far as we know, carbazolic porous organic frameworks enabling detection of I– and Hg2+ have not been reported.