Exceptionally Stable Microporous Organic Frameworks with Rigid Building Units for Efficient Small Gas Adsorption and Separation

Three microporous organic frameworks (hereafter denoted as MPOF-Ads) based on a rigid adamantane core have been successfully synthesized via Sonogashira–Hagihara polycondensation coupling in high yields, 83.7–94.6%. The obtained amorphous MPOF-Ads networks have high Brunauer–Emmett–Teller surface areas (up to 737.3 m2 g–1), narrow pore size distribution (0.95–1.06 nm), and superior thermal (the initial decomposition temperature T5% under an N2 atmosphere can reach 410 °C) and chemical stability (no apparent degradation in common organic solvents or strong acid/base solutions after 7 days). At 273 K and 1.0 bar, these MPOF-Ads networks present good uptake capacities for small gas molecules (13.9 wt % CO2 and 1.66 wt % CH4) for which the presence of high surface area, predominant microporosity, and narrow pore size distribution are beneficial. In addition, the as-prepared MPOF-Ads networks possess moderate isosteric heats for CO2 (Qst = 19.5–30.3 kJ mol–1) and show desired CO2/N2 and CO2/CH4 selectivity (36.3–38.4 and 4.1–4.3 based on Henry’s law and 17.88–24.92 and 4.24–5.70 based on ideal adsorbed solution theory, respectively). With the demonstrated properties, the synthesized MPOF-Ads networks display potential for small gas storage and separation that can be used in harsh environments because of their superior physical and chemical stability.