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Bismuth(III)-catalysed hydroalkylation of styrene with acetylacetone: a DFT-Based mechanistic study
journal contribution
posted on 2023-05-21, 09:36 authored by Jalali, M, Shiri, F, Alexander BissemberAlexander Bissember, Brian YatesBrian Yates, Alireza AriafardAlireza AriafardDensity functional theory (DFT) has been used to investigate the mechanism of the experimentally efficient hydroalkylation of styrene with acetylacetone in the presence of a bismuth catalyst. It is shown that the mechanism is fundamentally different to that of the analogous gold-catalysed reaction, even though it leads to the same product. Whereas gold prefers to coordinate to the π-bond of the enol isomer of acetylacetone, bismuth coordinates to the two oxygens to form a chelated complex. Furthermore, the overall reaction with bismuth via the enol isomer of acetylacetone occurs with a much lower activation energy compared to the ketone isomer. In addition, several bismuth catalysts were considered and two of these were shown to have no activity. All of these results have been rationalised in terms of the strength of binding of the metal centres to the acetylacetone. The stronger the binding, the greater the acidity of a proton on acetylacetone, and thus the lower the activation energy for the protonation of styrene, which turns out to be the rate-determining step in the overall reaction. In this way, good agreement is obtained with all the experimental data.
History
Publication title
Molecular PhysicsArticle number
e2093798Number
e2093798Pagination
1-15ISSN
0026-8976Department/School
School of Natural SciencesPublisher
Taylor & Francis LtdPlace of publication
4 Park Square, Milton Park, Abingdon, England, Oxon, Ox14 4RnRights statement
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