Bimetallic Be/Cu Pillared-Layered Porous Coordination Polymer for Selective CO2 Removal via Adsorption

The rational exploration of new chemical configurations within the structural confinements of porous coordination polymers (PCPs) continues to play a major role in developing novel functional adsorbents. In this respect, a bimetallic beryllium/copper [Cu2(pzdc)2(Be­(pyac)2)] n [pzdc: pyrazine-2,3-dicarboxylate; Be­(pyac)2: Bis­[3-(4-pyridyl)­pentane-2,4-dionato]­beryllium­(II)] pillared-layered PCP was synthesized for the first time. N2 (−196 °C) and CO2 (−78 °C) equilibrium adsorption data confirmed a microporous complex with a surface area of about 284 m2 g–1. A thermal gravimetric analysis showed that the PCP is thermally stable to about 250 °C. Moreover, in situ high-temperature powder X-ray diffraction showed that the metal–organic structure reversibly contracts or expands upon the presence of a guest species (i.e., water) or temperature. The bimetallic Be/Cu complex also displayed strong CO2-adsorbent interactions, evidenced by a larger heat of adsorption (41 kJ mol–1) compared to similar but monometallic PCPs. Furthermore, the Be/Cu PCP exhibited an ideal adsorbed solution theory (IAST) selectivity >60 for separating CO2/N2 (15:85) mixtures at 25 °C and 1 atm, which is higher than the values obtained for monometallic PCPs.