Bollini, Praveen2023-01-15May 20222022-05-10Portions of this document appear in: Hall, J.N., Bollini, P., Quantification of Open-Metal Sites in Metal−Organic Frameworks Using Irreversible Water Adsorption, Langmuir 36 (2020) 1345-1356; and in: Hall, J.N., Bollini, P., Enabling Access to Reduced Open-Metal Sites in Metal-Organic Framework Materials through Choice of Anion Identity: The Case of MIL-100(Cr), ACS Materials Letters 2 (2020) 838-844; and in: Hall, J.N., Bollini, P., Low-Temperature, Ambient Pressure Oxidation of Methane to Methanol Over Every Tri-Iron Node in a Metal-Organic Framework Material, Chemistry – A European Journal 26 (2020) 16639-16643; and in: Hall, J.N., Bollini, P., Role of Metal Identity and Speciation in the Low-Temperature Oxidation of Methane over Tri-Metal Oxo Clusters, AIChE Journal 67 (2021) e17496; and in: Hall, J.N., Bollini, P., Metal-Organic Framework MIL-100 Catalyzed Acetalization of Benzaldehyde with Methanol: Lewis or Brønsted Acid Catalysis?, ACS Catalysis 10 (2020) 3750 – 3763).https://hdl.handle.net/10657/13335Metal-organic frameworks (MOFs) are a class of crystalline materials featuring uniform distributions of inorganic nodes interconnected within well-defined organic porous environments. For applications in catalysis, the homogeneity of active centers attainable within MOFs enables achieving a level of clarity into structure-catalytic property relationships and reaction mechanisms beyond which can be realized in synthetic catalysts delimited by a high degree of heterogeneity in active site speciation – a feature of particular importance in the development of biomimetic catalysts. Herein, we demonstrate MIL-100 (MIL = Materials of Institut Lavoisier), a prototypical MOF featuring mixed-valent trinuclear metal nodes [M2+(M3+)2O], features an active site pool which is uniform in structure and catalytic performance. A combination of in-situ infrared spectroscopic characterization and probe molecule adsorption experiments with H2O, NO, and CO evidence the accessibility of the near theoretical density of coordinatively unsaturated divalent and trivalent open-metal sites within the Cr- and Fe-analogues of MIL-100 through facile thermal activation protocols (≤ 523 K, inert or vacuum). Furthermore, we demonstrate the activated catalysts effectuate the gas-phase stoichiometric oxidation of CH4 with N2O to partial oxygenates (methanol and acetaldehyde) through the involvement of every potentially available M2+ open-metal site. Carbon monoxide is applied as a reductant to further elucidate reaction steps that mediate redox turnovers with N2O over MIL-100. Transient, steady-state, and isotopic kinetic analyses provide novel insight into levers for tuning the kinetic relevance of specific reduction and oxidation elementary reaction steps through second-sphere coordination effects and identity of the active metal.application/pdfengThe author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. UH Libraries has secured permission to reproduce any and all previously published materials contained in the work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).Metal-organic frameworksCatalysis2023-01-15Thesisborn digital