Bimetallic-Organic Framework as a Zero-Leaching Catalyst in the Aerobic Oxidation of Cyclohexene

• Published in: ChemCatChem Vol. 5; no. 12; pp. 3657 - 3664
• Main Authors: Liu, Ying-Ya, Leus, Karen, Bogaerts, Thomas, Hemelsoet, Karen, Bruneel, Els, Van Speybroeck, Veronique, Van Der Voort, Pascal
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.12.2013; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: ab initio calculations; copper; epoxidation; heterogeneous catalysis; metal-organic framework; Oxidation
• ISSN: 1867-3880; 1867-3899
• DOI: 10.1002/cctc.201300529

A gallium 2,2′‐bipyridine‐5,5′‐dicarboxylate metal–organic framework (MOF), denoted as COMOC‐4, has been synthesized by solvothermal synthesis. This MOF exhibits the same topology as MOF‐253. CuCl2 was incorporated into COMOC‐4 by a post‐synthetic modification (PSM). The spectroscopic absorption properties of the MOF framework before and after PSM were compared with theoretical data obtained by employing molecular dynamics combined with time‐dependent DFT calculations on both the as‐synthesized and functionalized linker. The catalytic behavior of the resulting Cu2+@COMOC‐4 material was evaluated in the aerobic oxidation of cyclohexene with isobutyraldehyde as a co‐oxidant. In addition, the catalytic performance of Cu2+@COMOC‐4 was compared with that of the commercially available Cu‐BTC (BTC=benzene‐1,3,5‐tricarboxylate) MOF. Cu2+@COMOC‐4 exhibits a good cyclohexene conversion and an excellent selectivity towards cyclohexene oxide in comparison to the Cu‐based reference catalyst. Furthermore, no leaching of the active Cu sites was observed during at least four consecutive runs. MOF with claws: COMOC‐4, a gallium‐based metal–organic framework is synthesized, which contains open bipyridine sites on which CuCl2 is anchored. The catalytic performance of Cu2+@COMOC‐4 is evaluated for the aerobic oxidation of cyclohexene. The bimetallic–organic framework shows an excellent selectivity towards cyclohexene oxide and has good stability and reusability.