Rational Fine‐Tuning of MOF Pore Metrics: Enhanced SO 2 Capture and Sensing with Optimal Multi‐Site Interactions

Abstract Selective capture of sulfur dioxide (SO 2 ), important in the context of environmental protection, is reachable by specially tailored porous materials endowed with physisorptive complementarity. Metal–organic frameworks (MOFs) can potentially be leading materials for physisorptive SO 2 capture due to their excellent tailorability. Here, a series of highly stable DMOFs, [Ni 2 L 2 (DABCO)], where L = 1,4‐benzenedicarboxylate (BDC), 1,4‐naphthalenedicarboxylate (NDC), 2,6‐naphthalenedicarboxylate (2,6‐NDC), 9,10‐anthracendicarboxylate (ADC), and 1,4‐diazabicyclo[2,2,2]octane (DABCO) aiming at optimal SO 2 physisorption characteristics, is reported. The extension of the aromatic core by conjugated benzene rings allows to reach an optimal pore diameter at 4–5 Å in the case of the DMOF‐ADC, maximizing the multi‐site MOF···SO 2 interactions, which improve the SO 2 binding at low concentrations, as revealed by density‐functional theory (DFT) calculations. The improved SO 2 separation performance of DMOF‐ADC is demonstrated by single SO 2 and SO 2 /CO 2 ‐mixed‐component adsorption (a SO 2 /CO 2 selectivity >100 is reached at 0.01 bar, which is significantly better than the value for the benchmark DUT‐8 material) and dynamic breakthrough experiment. The use as a chemiresistive sensor for SO 2 sensing is demonstrated for the best performing DMOF‐ADC at low concentrations (doubled resistive response at 100 ppm and T < 120 °C).