- Metal-Organic Framework with Dual Active Sites in Engineered Mesopores for Bioinspired Synergistic Catalysis
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Here we report the design of an enzyme-inspired metal-organic framework (MOF), 1-OTf-Ir, by installing strong Lewis acid and photoredox sites in engineered mesopores. Al-MOF (1), with mixed 2,2′-bipyridyl-5,5-dicarboxylate (dcbpy) and 1,4-benzenediacrylat
- Quan, Yangjian,Song, Yang,Shi, Wenjie,Xu, Ziwan,Chen, Justin S.,Jiang, Xiaomin,Wang, Cheng,Lin, Wenbin
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- Modulation of the reactivity, stability and substrate- and enantioselectivity of an epoxidation catalyst by noncovalent dynamic attachment of a receptor functionality - Aspects on the mechanism of the Jacobsen-Katsuki epoxidation applied to a supramolecular system
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The synthesis of the components of the dynamic supramolecular hydrogen-bonded catalytic system 2 + 3 is described. The catalytic performance and substrate- and enantioselectivity of Mn(salen) catalyst 2 were investigated in the presence and absence of the Zn(porphyrin) receptor unit 3. The effects of pyridine and pyridine N-oxide donor ligands were also studied. Some aspects on the mechanism of the Jacobsen-Katsuki epoxidation, based on literature observations, are introduced as a means to analyse the behaviour of 2 and its modulation by the formation of macrocycle 1 with 3. A complete association model of the metal-free system 4 + 5 refutes the earlier assumption that macrocycle 1 is the predominant form of catalyst 2 under the standard epoxidation reaction conditions with 2 + 3. Evidence are provided that receptor-binding substrates and nonbinding substrates, respectively, are epoxidised by two different catalytic species, or two distinct distributions of species in competitive epoxidations using catalytic system 2 + 3. The two species are assigned to the endo and exo faces of the Mn(salen) catalyst in macrocycle 1, and to equivalently folded oligomeric structures with monomers 2 and 3 in adjacent positions. The Royal Society of Chemistry 2006.
- Jonsson, Stefan,Odille, Fabrice G. J.,Norrby, Per-Ola,Waernmark, Kenneth
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p. 1927 - 1948
(2008/02/03)
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