Nitrogen‐Rich Mn‐Based Metal–Organic Frameworks for Small Molecule Adsorption and Activation through Polarization

Abstract To address the far‐reaching consequences of radioiodine contamination and CO 2 emissions, heteroatom engineering in materials has emerged as a promising strategy. In this study, three thermally and chemically stable Mn‐based metal–organic frameworks (MOFs), 1 – 3 , are synthesized using (i) a dicarboxylate ligand with an oxadiazole core, and (ii) nitrogen‐rich ligands with varying spacers between the bis(tridentate) ends. The incorporation of a heterocyclic core and nitrogen atoms enhances polarity, while Lewis acidity of Mn 2+ ion strengthens small molecule interactions. The strong iodine uptake, both in vapor (2.9–2.2 g g −1 ) and aqueous phases (1.82–1.34 g g −1 ), underscores their effectiveness in radioactive iodine remediation. Notably, these selectively capture iodide ions even in the presence of competing anions. The polar nature of 1 – 3 is also evidenced by CO₂ [isosteric heat of adsorption ( Q st ): 30 kJ mol −1 ] and H 2 O (uptake range: 7.77–11.48 mmol g −1 ) sorption studies. Exploiting their Lewis acidity and polar sites, 1 – 3 efficiently catalyze a solvent‐free CO 2 fixation reaction with epoxide and aniline, yielding oxazolidinones with high conversions and turnover numbers. The configurational biased Monte Carlo (CBMC) simulations confirm interactions of 1 – 3 with ionic iodine and reactants of catalysis. These MOFs demonstrate excellent reusability, maintaining structural integrity without any metal leaching.