A5080434968- Organometallic Complex Synthesis and Catalysis
- Catalysis and Oxidation Reactions
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Catalytic Processes in Materials Science
- Magnetism in coordination complexes
- Mesoporous Materials and Catalysis
- Carbon dioxide utilization in catalysis
- Inorganic Chemistry and Materials
- Machine Learning in Materials Science
- Advanced NMR Techniques and Applications
- Lanthanide and Transition Metal Complexes
- Catalysis and Hydrodesulfurization Studies
- Organoboron and organosilicon chemistry
- Asymmetric Hydrogenation and Catalysis
- Metal-Organic Frameworks: Synthesis and Applications
- Synthetic Organic Chemistry Methods
- Radioactive element chemistry and processing
- Advanced materials and composites
- Advanced Polymer Synthesis and Characterization
- Coordination Chemistry and Organometallics
- Polyoxometalates: Synthesis and Applications
- Advanced Chemical Physics Studies
ETH Zurich
2018-2024
Moscow Institute of Thermal Technology
2023
MIT University
2023
École d'Ingénieurs en Chimie et Sciences du Numérique
2020-2021
Centre National de la Recherche Scientifique
2020-2021
Paul Scherrer Institute
2020-2021
Shell (Netherlands)
2020-2021
Board of the Swiss Federal Institutes of Technology
2020
Propane dehydrogenation is an important industrial reaction to access propene, the world's second most used polymer precursor. Catalysts for this transformation are required be long living at high temperature and robust toward harsh oxidative regeneration conditions. In work, combining surface organometallic chemistry thermolytic molecular precursor approach, we prepared well-defined silica-supported Pt alloyed PtZn materials investigate effect of Ti-doping on catalytic performances....
Despite decades of extensive studies, the atomic-scale structure active sites in heterogeneous Ziegler–Natta (ZN) catalysts, one most important processes chemical industry, remains elusive and a matter debate. In present work, ZN catalysts absence ethylene, referred to as dormant sites, is elucidated from magnetic resonance experiments carried out on samples reacted with increasing amounts BCl3 so enhance concentration observe clear spectroscopic signatures. Using electron paramagnetic (EPR)...
The combined use of magnetic resonance spectroscopies (EPR and solid-state NMR) computational approaches enable the determination electronic structure geometry a paramagnetic Yb( iii ) alkyl complex.
Abstract The selective conversion of methane to methanol remains one the holy grails chemistry, where Cu‐exchanged zeolites have been shown promote this reaction under stepwise conditions. Over years, several active sites proposed, ranging from mono‐, di‐ trimeric Cu II . Herein, we report formation well‐dispersed monomeric species supported on alumina using surface organometallic chemistry and their reactivity towards methanol. Extensive studies various transition supports combined with...
Ti( iii ) alkyl species polymerize ethylene via an original mechanism, which involves back donation to the π*(C 2 H 4 and a delocalization of unpaired electron in transition state C insertion into partially alkylidenic )–C bond.
Abstract The structure of paramagnetic surface species is notoriously difficult to determine. For Ti III centers related Ziegler–Natta catalysis, we demonstrate here that detailed structural information can be obtained by advanced EPR spectroscopy and DFT computations, benchmarked on molecular analogs. hyperfine sublevel correlation (HYSCORE) spectra after reaction with 13 C‐labeled ethylene provides about the coupling a proton in first coordination sphere as well significant C thereby...
Abstract The selective conversion of methane to methanol remains one the holy grails chemistry, where Cu‐exchanged zeolites have been shown promote this reaction under stepwise conditions. Over years, several active sites proposed, ranging from mono‐, di‐ trimeric Cu II . Herein, we report formation well‐dispersed monomeric species supported on alumina using surface organometallic chemistry and their reactivity towards methanol. Extensive studies various transition supports combined with...
The Union Carbide (UC) ethylene polymerization catalysts, based on chromocene dispersed silica, show distinct features from the Phillips but share same heated debate regarding structure of their active sites. Based a combination IR, EPR spectroscopies, labeling experiments, and DFT modeling, we identified monomeric surface-supported Cr(iii) hydrides, ([triple bond, length as m-dash]SiO)Cr(Cp)-H, sites UC catalyst. These are formed in presence grafted adsorbed well residual surface OH groups,...
Despite decades of extensive studies, the atomic-scale structure active sites in heterogeneous Ziegler-Natta (ZN) catalysts, one most important processes chemical industry, remains elusive and a matter debate. In present work, “active sites” ZN catalysts absence ethylene, referred to as “dormant sites”, is elucidated from magnetic resonance experiments, carried out on samples reacted with increasing amounts BCl<sub>3</sub> so enhance concentration observe clear spectroscopic...
Abstract The structure of paramagnetic surface species is notoriously difficult to determine. For Ti III centers related Ziegler–Natta catalysis, we demonstrate here that detailed structural information can be obtained by advanced EPR spectroscopy and DFT computations, benchmarked on molecular analogs. hyperfine sublevel correlation (HYSCORE) spectra after reaction with 13 C‐labeled ethylene provides about the coupling a proton in first coordination sphere as well significant C thereby...
Abstract The ethylene polymerization Phillips catalyst has been employed for decades and is central to the polymer industry. While Cr(III) alkyl species are proposed be propagating sites, there so far no direct experimental evidence such proposal. In this work, by coupling Surface organometallic chemistry, EPR spectroscopy, machine learning‐supported XAS studies, we have studied electronic structure of well‐defined silica‐supported alkyls identified presence several surface in high low‐spin...
Stereoselective hydroaminoalkylation of alkenes via α-C–H bond activation alkylamines is an efficient process for the preparation complex minimizing stoichiometric waste. Herein, we report that a combination Cp*TiMe3 and AlMe3 catalyzes branch-selective 1-alkenes, including styrene derivatives 1,3-dienes, with N-methylaniline derivatives. Kinetic studies reveal active species are generated from in situ Cp*TiMe2(NMePh) alkylaluminum. Continuous wave (CW) pulse EPR spectroscopy show multiple...
Characterization of paramagnetic compounds, in particular regarding the detailed conformation and electronic structure, remains a challenge, - still today it often relies solely on use X-ray crystallography, thus limiting access to structure information. This is particularly true for lanthanide elements that are associated with peculiar structural features relation their partially filled f-shell. Here, we develop methodology based combined state-of-the-art magnetic resonance spectroscopies...
Despite decades of extensive studies, the atomic-scale structure active sites in heterogeneous Ziegler-Natta (ZN) catalysts remains elusive and a matter debate. Here, polymerization ZN is elucidated from magnetic resonance experiments carried out on samples reacted with increasing amounts BCl 3 so as to enhance concentration observe clear spectroscopic signatures. Notably, we show that EPR NMR spectroscopy activated enables paramagnetic species whose amount increases conjunction catalytic...
The Union Carbide(UC) catalyst, one of the first ethylene polymerization (EP) catalysts based on supported organometallic compounds, is chromocene dispersed silica; it distinct from corresponding Phillips catalysts, chromium oxide, because responsive to H2 enabling tuning resulting polymer. Yet, despite 50 years research, structure its active sites has also been controversially discussed and remains elusive. Based a combination IR, EPR spectroscopies, labeling experiments, modeling at DFT...
Characterization of paramagnetic compounds, in particular regarding the detailed conformation and electronic structure, remains a challenge - still today it often relies solely on use X-ray crystallography, thus limiting access to structure information. This is particularly true for lanthanide elements that are associated with peculiar structural features relation their partially filled f -shell. Here, we showcase state-of-the-art magnetic resonance spec- troscopy (EPR solid-state NMR)...
The ethylene polymerization Phillips catalyst has been employed for decades and is central to the polymer industry. While Cr(III) alkyl species are proposed be propagating sites, there so far no direct experimental evidence such proposal. In this work, by coupling Surface organometallic chemistry (SOMC), EPR spectroscopy, machine learning-supported XAS studies, we have studied electronic structure of well-defined silica-supported alkyls, identified presence several surface from high low spin...
Abstract The ethylene polymerization Phillips catalyst has been employed for decades and is central to the polymer industry. While Cr(III) alkyl species are proposed be propagating sites, there so far no direct experimental evidence such proposal. In this work, by coupling Surface organometallic chemistry, EPR spectroscopy, machine learning‐supported XAS studies, we have studied electronic structure of well‐defined silica‐supported alkyls identified presence several surface in high low‐spin...
The selective conversion of methane to methanol remains one the holy grails chemistry, where Cu-exchanged zeolites have been shown selectively convert under stepwise conditions. Over years, several active sites proposed, ranging from mono-, di- trimeric Cu(II). Herein, we report formation well-dispersed monomeric Cu(II) species supported on alumina using surface organometallic chemistry and their reactivity towards methanol. Extensive studies various transition supports combined with...