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Updated: Mar 29, 2026

Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks MOFs
Published on: January 17, 2020
Dynamic Intermediate Coordination on Cerium Dual Sites in MOFs Boosts Selective Epoxidation of Alkenes
Caoyu Yang1,2, Wei Liu2,3, Hanlin Liu1,2
1CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, P. R. China.
Abstract:
CeO2 is widely studied in catalysis but struggles with precise defect and microenvironment modulation. Here, we report modulating dynamic coordination and microenvironment of defective Ce pairs on Ce6-oxo clusters in cerium terephthalate UiO-66 for selective oxidation. With one coordinative vacancy per Ce site in dual-site pairs, cerium 2-fluoroterephthalate UiO-66 exhibits excellent styrene epoxidation with 87.7% styrene oxide selectivity at near-complete conversion using O2 and isobutyraldehyde at 50°C, while excess coordinative vacancies per Ce site reduce styrene oxide selectivity to 73.4%. Furthermore, F-substituted UiO-66 outperforms terephthalate (67.5%) and 2-methylterephthalate (60.7%) analogs, and CeO2 (54%). Mechanistic studies reveal that isobutyraldehyde initiates binding to defective Ce site, deprotonating and reacting with O2 to generate peroxo radicals that favor styrene vinyl C═C bond adsorption. Concurrently, vinyl C═C bond and adjacent defective Ce site co-interact with O2 to form robust Ce─O bond, where activated O2 undergoes configuration transition from linear to side-on, inducing dynamic switching of carboxylate groups between bidentate and monodentate coordination; meanwhile, F-substituted UiO-66 facilitates peroxo O─O cleavage and vinyl π bond cleavage, enhancing styrene oxide selectivity over H/CH3 counterparts. Substantially, F-substituted UiO-66 enables efficient epoxidation of diverse alkenes under mild condition.
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