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The livestream will be activated 15 minutes before the Defense starts.
Trial lecture
June 12, 10:15 Auditorium 3, Chemistry Building
Trial lecture title: “Approaches and Challenges in Oxidation of CH4”
Conferral summary / Kreeringssammendrag
Denne avhandlingen belyser aspekter ved metodeutvikling og anvendelse for katalytisk testing av bioinspirerte kobberbaserte systemer brukt til C–H-oksidasjon av hydrokarboner. Gjennom systematisk evaluering og karakterisering av nøkkelintermediater i utvalgte homogene og heterogene systemer ble den DFT-baserte katalytiske syklusen verifisert. De resulterende mekanistiske innsiktene og reaktivitetsprofilene ble deretter sammenlignet med deres enzymatiske motparter, og gir et grunnlag for videre utvikling av fremtidige katalysatorer.
Main research findings / Hovedfunn
Many Cu-based systems were designed by other members of CuBE-Synergy project replicating the active center of monooxygenase enzymes. The designed catalysts were assessed across this work for C–H oxidation reaction using cyclohexane and cyclohexene as the substrates. The dominant reaction mechanism and the role of cosubstrate were substrate-dependant. Cyclohexane oxidation proceeded mainly via Fenton reactions along with a Cu(I)/Cu(II) redox cycle, where a ~1st order reaction kinetics with respect to Cu and the oxidant was observed. Cyclohexene oxidation, however, was dominated by radical chain mechanism in which the selectivity and reactivity profiles are not Cu-centred and rather influenced by other factors in the bulk (e.g. solvent and O2 availability). The consumption of the oxidant in the latter case was determined by its involvement as a chain terminator.
Considering the comparison of synthetic systems to their inspiring enzymes, turnover frequencies in our systems were ~four-orders of magnitude lower than the functional monooxygenases. Although the reactivity profile was later improved by over one-order of magnitude via optimizing the catalyst design and reaction parameters, this clear shift in reactivity showcases the essential role of substrate-binding modules, found in enzymes, in directing the catalytic reaction and minimizing the damage of the catalytic site.
Candidate contact information
www.linkedin.com/in/mouhammad-abu-rasheed/
E-mail: m.a.rasheed@kjemi.uio.no
Telephone: +47 922 63 137
Adjudication committee
Professor Maricruz Sanchez-Sanchez
Faculty of Technical Chemistry, Technical University of Vienna
Associate professor Miguel Rivero-Crespo,
Department of Organic Chemistry, Stockholm University
Professor Reidar Haugsrud
Department of Chemistry, University of Oslo
Chair of defence
Ute Krengel
Department of Chemistry, University of Oslo, Norway
Supervisors
Professor Unni Olsby
Department of Chemistry, University of Oslo, Norway
Head of Department/Professor Stian Svelle
Department of Chemistry, University of Oslo, Norway
Senior Researcher Ainara Nova,
Department of Chemistry, University of Oslo, Norway
Associate professor Evgeniy Redekop
Department of Chemistry, University of Oslo, Norway