Modulator-Dependent Dynamics Synergistically Enabled Record SO Uptake in Zr(IV) Metal-Organic Frameworks Based on Pyrene-Cored Molecular Quadripod Ligand.

Developing innovative porous solid sorbents for the capture and storage of toxic SO is crucial for energy-efficient transportation and subsequent processing. Nonetheless, the quest for high-performance SO sorbents, characterized by exceptional uptake capacity, minimal regeneration energy requirements, and outstanding recyclability under ambient conditions, remains a significant challenge. In this study, we present the design of a unique tertiary amine-embedded, pyrene-based quadripod-shaped ligand. This ligand is then assembled into a highly porous Zr-metal-organic framework (MOF) denoted as Zr-TPA, which exhibits a newly discovered 3,4,8-c net structure. Remarkably, our Zr-TPA MOF achieved an unprecedented SO sorption capacity of 22.7 mmol g at 298 K and 1 bar, surpassing those of all previously reported solid sorbents. We elucidated the distinct SO sorption behaviors observed in isostructural Zr-TPA variants synthesized with different capping modulators (formate, acetate, benzoate, and trifluoroacetate, abbreviated as FA, HAc, BA, and TFA, respectively) through computational analyses. These analyses revealed unexpected SO-induced modulator-node dynamics, resulting in transient chemisorption that enhanced synergistic SO sorption. Additionally, we conducted a proof-of-concept experiment demonstrating that the captured SO in Zr-TPA-FA can be converted in situ into a valuable pharmaceutical intermediate known as aryl -aminosulfonamide, with a high yield and excellent recyclability. This highlights the potential of robust Zr-MOFs for storing SO in catalytic applications. In summary, this work contributes significantly to the development of efficient SO solid sorbents and advances our understanding of the molecular mechanisms underlying SO sorption in Zr-MOF materials.