Synthesis and characterization of phenanthroimidazole-containing triazine frameworks and their performance in CO2 capture

Abstract In this work, two building blocks with similar structure, namely, 2-(4-cyanophenyl)-1H-phenanthro[9,10-d]imidazole-6,9-dicarbonitrile (CPI) and 4,4′,4''-(1H-phenanthro[9,10-d]imidazole-2,6,9-triyl)tribenzonitrile (BPI), were synthesized. Then the CPI- and BPI-derived, covalent triazine-based frameworks (namely, CTF-CPIs and CTF-BPIs) were synthesized by ZnCl2-triggered polytrimerization under different conditions including molar ratio of building block to ZnCl2 and polytrimerization temperature. The obtained CTF-CPIs and CTF-BPIs both were amorphous with specific surface areas up to 1501 m2 g−1 and 1775 m2 g−1, respectively, for the CTF-CPI-7 and CTF-BPI-6. Meanwhile, the CO2 capture performance of CTF-CPIs and CTF-BPIs was studied and the CO2 uptake capacity and CO2/N2 selectivity were determined to be 3.80 mmol g−1/22.7 and 3.26 mmol g−1/16.4, respectively, for the CTF-CPI-4 and CTF-BPI-5 at 273 K.