Selektive C–H Oxidationsreaktionen in katalytisch aktiven Metallorganischen Gerüstverbindungen (MOFs)
Festkörper- und Oberflächenchemie, Materialsynthese
Organische Molekülchemie - Synthese, Charakterisierung
Zusammenfassung der Projektergebnisse
The efficient conversion of light hydrocarbons from natural gas to valuable alcohols with abundant O2 remains an important challenge in the global effort to limit greenhouse gas emissions. Nature uses nonheme iron enzymes that generate high-spin Fe(IV)=O species for hydrocarbon C–H bond oxygenation reactions. Synthetic chemists have long tried to mimic such reactivity, however, the enzyme-like activation of O2 to form reactive high-spin Fe(IV)=O species remains an unsolved problem. In my postdoctoral work in the Long group at UC Berkeley, I developed a metal–organic framework that mimics the reactivity of αketoglutarate dependent dioxygenases. The framework forms high-spin (S = 2) Fe(IV)=O species by treatment with O2 at low temperatures that are characterized by in situ diffuse reflectance infrared Fourier transform, in situ and variable-field Mössbauer, Fe Kβ x-ray emission, and nuclear resonance vibrational spectroscopies. In the presence of O2, the framework is a competent catalyst for cyclohexane oxidation and can oxidize ethane to ethanol in a stoichiometric fashion. Extension of the reactivity with respect to catalytic conversion of methane to methanol and selectivity effects for the oxygenation of more complex substrates guided by the pore environment are current research efforts. This project resulted from a modification of my original DFG postdoctoral fellowship proposal, for which I identified and proposed metal–organic frameworks as suitable heterogenous catalysts for hydrocarbon oxygenation reactivity and as promising platforms for the characterization of new reactive transition metal species. Both aspects have been realized in my postdoctoral studies, opening a new research area with many projects to follow. R. Sanders, “Capturing wellhead gases for profit and a cleaner environment”, Berkeley News, November 13, 2023. “How lab-made catalysts can help to get a grip on difficult greenhouse gases”, Max-Planck-Institut für Kohlenforschung News.
Projektbezogene Publikationen (Auswahl)
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Reactive high-spin iron(IV)-oxo sites through dioxygen activation in a metal–organic framework. Science, 382(6670), 547-553.
Hou, Kaipeng; Börgel, Jonas; Jiang, Henry Z. H.; SantaLucia, Daniel J.; Kwon, Hyunchul; Zhuang, Hao; Chakarawet, Khetpakorn; Rohde, Rachel C.; Taylor, Jordan W.; Dun, Chaochao; Paley, Maria V.; Turkiewicz, Ari B.; Park, Jesse G.; Mao, Haiyan; Zhu, Ziting; Alp, E. Ercan; Zhao, Jiyong; Hu, Michael Y.; Lavina, Barbara ... & Long, Jeffrey R.
