Hani M. El‐Kaderi

Three-dimensional covalent organic frameworks (3D COFs) were synthesized by targeting two nets based on triangular and tetrahedral nodes: ctn and bor. The respective 3D COFs were synthesized as crystalline solids by condensation reactions of tetrahedral tetra(4-dihydroxyborylphenyl) methane or tetra(4-dihydroxyborylphenyl)silane and by co-condensation of triangular 2,3,6,7,10,11-hexahydroxytriphenylene. Because these materials are entirely constructed from strong covalent bonds (C-C, C-O, C-B, and B-O), they have high thermal stabilities (400 degrees to 500 degrees C), and they also have high surface areas (3472 and 4210 square meters per gram for COF-102 and COF-103, respectively) and extremely low densities (0.17 grams per cubic centimeter).

Three new crystalline microporous and mesoporous 2D covalent organic frameworks termed COF-6, -8, and -10 from boronic acid building blocks and 2,3,6,7,10,11-hexahydroxytriphenylene have been synthesized and structurally characterized. These materials constructed of C2O2B rings form eclipsed layered structures with pore sizes ranging from 6.4 to 34.1 Å and are found to have high thermal stability, low density, and high porosity as indicated by the surface areas of 980, 1400, and 2080 m2 g-1 for COF-6, -8, and -10, respectively. The control of pore size and structure demonstrates the effectiveness of reticular chemistry methods toward materials design.

Porous organic polymers containing nitrogen-rich building units are among the most promising materials for selective CO2 capture and separation which can have a tangible impact on the environment and clean energy applications. Herein we report on the synthesis and characterization of four new porous benzimidazole-linked polymers (BILPs) and evaluate their performance in small gas storage (H2, CH4, CO2) and selective CO2 binding over N2 and CH4. BILPs were synthesized in good yields by the condensation reaction between aryl-o-diamine and aryl-aldehyde building blocks. The resulting BILPs exhibit moderate surface area (SABET = 599–1306 m2 g–1), high chemical and thermal stability, and remarkable gas uptake and selectivity. The highest selectivity based on initial slope calculations at 273 K was observed for BILP-2: CO2/N2 (113) and CO2/CH4 (17), while the highest storage capacity was recorded for BILP-4: CO2 (24 wt % at 273 K and 1 bar) and H2 (2.3 wt % at 77 K and 1 bar). These selectivities and gas uptakes are among the highest by porous organic polymers known to date which in addition to the remarkable chemical and physical stability of BILPs make this class of material very promising for future use in gas storage and separation applications.

Hole-some mixture: A 2D mesoporous covalent organic framework (see figure) featuring expanded pyrene cores and linked by imine linkages has a high surface area (SABET=2723 m2 g−1) and exhibits significant gas storage capacities under high pressure, which make this class of material very promising for gas storage applications. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

A highly porous benzimidazole-linked polymer (SABET 1172 m2/g) exhibits very high gas selectivity CO2/N2 (70) and CO2/CH4 (10) and can store CO2 (19 wt %, 273 K, 1 bar) and H2 (1.9 wt %, 77 K, 1 bar) with Qst values of 26.7 and 7.9 kJ/mol, respectively.