Multifunctional nitrogen-rich aminal-linked luminescent porous organic polymers for iodine enrichment and selective detection of Fe3+ ions

Abstract

Development of multifunctional porous organic polymers containing heteroatoms is of significant importance for practical environmental applications including sequestering of greenhouse gasses, radioactive nucleotides, and heavy metals ions. In this work, two nitrogen-rich aminal-linked luminescent porous organic polymers (NRAPOP-1 and NRAPOP-2) bearing anthracene moiety were successfully synthesized by reacting 9,10-bis-(4,6-diamino-S-triazin-2-yl)anthracene with 1,4-dibenzaldehyde or thieno[2,3-b]thiophene-2,5-dicarbaldehyde through one-pot Schiff base condensation reaction. NRAPOP-1 and NRAPOP-2 exhibit permanent porosity with Brunauer–Emmett–Teller (BET) surface areas of 544 m2 g−1 and 424 m2 g−1, respectively. Structural analysis, elemental composition, thermal stability, and morphology studies were conducted using Fourier transform infrared spectroscopy, elemental analysis, thermogravimetric analysis, and scanning electron microscopy. The two newly synthesized polymers showed excellent adsorption of iodine vapor with an uptake of up to 281 wt.% at 80 °C and 1 bar, which is among the highest value reported to date for aminal-linked porous organic polymers. Furthermore, fluorescence spectroscopic investigations of aqueous suspensions of the NRAPOPs revealed selective fluorescence quenching by metal ions with high sensitivity for Fe3+ ions. The strategy of constructing highly porous organic polymers by linking heteroatom-rich building blocks that also comprise luminescent moieties should pave the way for the preparation of novel materials for multienvironmental applications.