Article
Chemistry, Physical
Anne V. Le, Biplab Rajbanshi, Raul F. Lobo, Peng Bai
Summary: In this study, DFT calculations were used to investigate the mechanisms of propene metathesis catalyzed by WOx/SiO2. The results showed that there are still many mechanisms of heterogeneous catalyzed metathesis reactions that are not well understood. The pseudo-Wittig mechanism was found to be the most favorable method for generating initial alkylidene active sites. The allylic and vinylic C-H activations are more difficult and require the reduction of surface sites to W(+4).
JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Jessica Rodriguez, Maxime Boudjelel, Leonard J. Mueller, Richard R. Schrock, Matthew P. Conley
Summary: This passage describes the reaction of W(NAr) ((C4H8)-C-13) (OSiPh3)(2) (1) with partially dehydroxylated silica at 700 degrees C. The results show that the reaction outcome is highly influenced by the reaction conditions. Different compounds are formed as products, and their formation is affected by light and heating treatment.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Pratya Promchana, Kittisak Choojun, Wanwisa Limphirat, Yingyot Poo-arporn, Tawan Sooknoi
Summary: Acetylene in ethylene-rich feed can be removed via acetylene/ethylene cross-metathesis over WO3-supported catalysts at 450 degrees C, yielding 1,3-butadiene with cyclohexene as a minor product. The catalyst must be treated with ethylene at 600 degrees C to generate a genuinely active site of tungsten (IV) alkylidene species (W=CH2). The H2 treatment decreases surface W--O concentration, and hence the activity.
APPLIED CATALYSIS A-GENERAL
(2023)
Article
Chemistry, Inorganic & Nuclear
Jordan De Jesus Silva, Margherita Pucino, Feng Zhai, Deni Mance, Zachariah J. Berkson, Darryl F. Nater, Amir H. Hoveyda, Christophe Coperet, Richard R. Schrock
Summary: In this study, the catalytic performances of molybdenum oxo alkylidene species with different anionic O ligands were evaluated in metathesis reactions of internal and terminal olefins. It was found that the presence of the ORF9 ligand significantly increased catalytic activity, particularly in the molecular form. In contrast, molecular complexes with large aryloxy anionic ligands showed little activity, while their silica-supported counterparts exhibited improved activity.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Mathis J. Benedikter, Janis V. Musso, Wolfgang Frey, Roman Schowner, Michael R. Buchmeiser
Summary: Despite their excellent selectivities and activities, Mo- and W-based catalysts for olefin metathesis have not been widely used due to their air sensitivity. The synthesized cationic-at-metal molybdenum and tungsten imido alkylidene NHC nitrile complexes are stable in air and can catalyze olefin metathesis reactions without prior activation. The presence of a nitrile ligand is crucial for their stability, while variations in imido and anionic ligands affect reactivities and stability.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Somsuvra Banerjee, Takafumi Kobayashi, Kazuhiko Takai, Sobi Asako, Laurean Ilies
Summary: In the presence of triphenylphosphine as a mild reductant, the use of catalytic amounts of Mo(CO)6 and an ortho-quinone ligand enables the intermolecular reductive coupling of aromatic aldehydes and the intramolecular coupling of aromatic ketones to produce functionalized alkenes. Diaryl-and diheteroaryl alkenes are synthesized with high (E)-selectivity and a tolerance toward bromide, iodide, and steric hindrance. Intramolecular coupling of dicarbonyl compounds under similar conditions affords mono-and disubstituted phenanthrenes.
Article
Chemistry, Inorganic & Nuclear
Alina D. Mironova, Maksim A. Mikhaylov, Alexander M. Maksimov, Konstantin A. Brylev, Artem L. Gushchin, Dmitry Stass, Alexander S. Novikov, Ilia Eltsov, Pavel A. Abramov, Maxim N. Sokolov
Summary: In this study, a series of novel cluster complexes were synthesized and characterized. These clusters exhibit unique crystal structures and display efficient photoluminescence and X-ray luminescence properties.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Wenxing Zou, Qihao Zhu, James C. Fettinger, Philip P. Power
Summary: This study synthesized two dimeric copper thiolato species and characterized their structures. These complexes have specific core structures similar to the interactions of copper atoms in nitrous oxide reductase.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Inorganic & Nuclear
Tuhin Ganguly, Abhijit Bera, Anuj Baran Chakraborty, Amit Majumdar
Summary: A new and efficient catalytic hydrolysis method for aliphatic and aromatic thiolates under ambient conditions is presented. The previous stoichiometric reaction product is shown to act as an efficient catalyst for the hydrolysis of a broad range of thiolates, producing alcohols/phenols. The reaction proceeds in DMF at room temperature.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Julius Hillenbrand, J. Nepomuk Korber, Markus Leutzsch, Nils Noethling, Alois Fuerstner
Summary: Molybdenum alkylidyne complexes with a trisilanolate podand ligand framework are highly selective catalysts for alkyne metathesis, with complex 1a being the most reactive but requiring high loadings in certain applications. These catalysts decompose readily via a bimolecular pathway, but increasing the size of peripheral substituents on silicon can largely avoid this rapid degradation.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Physical
Janis Musso, Roman Schowner, Laura Falivene, Wolfgang Frey, Luigi Cavallo, Michael R. Buchmeiser
Summary: A series of cationic tungsten oxo alkylidene N-heterocyclic carbene (NHC) complexes were synthesized and characterized by single crystal X-ray diffraction. The correlation between the C-13 NMR chemical shifts of alkylidene C atoms and the DFT calculated chemical shifts was studied, revealing a good correlation and strong correlation with the rate of ring-closing metathesis. Analysis of catalyst geometries and magnetic shielding tensors allowed for assigning different structures to different levels of shielded alkylidene C atoms and corresponding reaction rates.
Review
Chemistry, Multidisciplinary
Maciej D. Korzynski, Christophe Coperet
Summary: One of the goals of modern catalysis science is to form single-site catalysts with uniform structure and identical affinity. Achieving such characteristics is challenging due to the complexity of surface chemical reactions. Surface organometallic chemistry has emerged as an effective method for forming well-defined species.
TRENDS IN CHEMISTRY
(2021)
Article
Chemistry, Inorganic & Nuclear
Michael R. Buchmeiser, Dominik Imbrich, Dongren Wang, Stefan Naumann
Summary: The authors synthesized a series of tungsten (VI) imido alkylidene N-heterocyclic olefin (NHO) complexes and found that the catalysts showed improved activity in ring-closing metathesis by adjusting the number and type of NHO ligands. The results indicate that further optimization of the catalysts' performance can be achieved by ligand tuning.
JOURNAL OF ORGANOMETALLIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
N. Hongrutai, S. Watmanee, S. Wannakao, P. Praserthdam, J. Panpranot
Summary: In this study, the surface silanol structures, acid properties, and tungsten dispersion of sol-gel-derived 7W/SiO2-xAl2O3 catalyst were investigated using various analytical techniques. The addition of 1 wt% Al2O3 was found to effectively preserve the Si(OH)Al structure, leading to the best catalytic performance in propene self-metathesis reaction.
MATERIALS TODAY CHEMISTRY
(2021)
Article
Energy & Fuels
N. Asikin-Mijan, G. AbdulKareem-Alsultan, M. S. Mastuli, A. Salmiaton, Mohamad Azuwa Mohamed, H. V. Lee, Y. H. Taufiq-Yap
Summary: Bifunctional Co-W catalysts were prepared for the catalytic deoxygenation-cracking of tung oil to produce jet fuel fractions. The CoW/SA catalyst showed the highest activity and outperformed the monometallic Co and W catalysts. It was found that excessively high metal dosages led to over cracking, while lower metal dosages effectively controlled over cracking. The resulting TO-jet fuel had excellent physicochemical properties and combustion characteristics.
Article
Chemistry, Multidisciplinary
Anna Giorgia Nobile, David Trummer, Zachariah J. Berkson, Michael Worle, Christophe Coperet, Pierre-Adrien Payard
Summary: The structure of the surface sites of the Union Carbide ethylene polymerization catalyst remains elusive, but recent research suggests the presence of monomeric and dimeric Cr(ii) sites, as well as Cr(iii) hydride sites. However, the analysis of their structure is complicated by large paramagnetic H-1 shifts induced by unpaired electrons on the Cr atoms. In this study, a cost-efficient DFT methodology was implemented to calculate the H-1 chemical shifts for antiferromagnetically coupled metal dimeric sites, allowing for the assignment of observed H-1 shifts for the industrial-like UC catalyst and confirming the presence of monomeric and dimeric Cr(ii) sites as well as dimeric Cr(iii)-hydride sites.
Article
Chemistry, Multidisciplinary
Maximilian Krodel, Lorenz Abduly, Manouchehr Nadjafi, Agnieszka Kierzkowska, Alexander Yakimov, Alexander H. Bork, Felix Donat, Christophe Coperet, Paula M. Abdala, Christoph R. Mueller
Summary: Understanding the effects of different structural parameters of CaO-based CO2 sorbents on cyclic CO2 uptake is crucial for their advancement. Through mechanochemical activation, CaO-based sorbents with varying ratios of Na2CO3:CaCO3 were synthesized to investigate the impact of sodium species on the sorbents' structure, morphology, carbonation rate, and cyclic CO2 uptake. The addition of Na2CO3 in the range of 0.1-0.2 mol% significantly improved CO2 uptake by up to 80% after 10 cycles compared to untreated CaCO3, while higher Na2CO3 loadings (>0.3 mol%) led to a decrease of more than 40% in cyclic CO2 uptake due to accelerated deactivation caused by sintering and the presence of crystalline Na2Ca(CO3)(2) species with high mobility of Na.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Editorial Material
Chemistry, Multidisciplinary
Thomas R. Ward, Christophe Coperet
Article
Chemistry, Multidisciplinary
Paco Laveille, Pascal Mieville, Sourav Chatterjee, Elisa Clerc, Jean-Charles Cousty, Florian de Nanteuil, Erwin Lam, Edy Mariano, Adrian Ramirez, Urielle Randrianarisoa, Keyan Villat, Christophe Coperet, Nicolai Cramer
Summary: The Catalysis Hub - Swiss CAT+ is a funded infrastructure project jointly led by EPFL and ETHZ, which provides a unique integrated technology platform for automated and high-throughput experimentation in sustainable catalytic technologies. Divided into two hubs, EPFL focuses on homogeneous catalysis while ETHZ focuses on heterogeneous catalysis, the platform is open to both academic and private research groups. Through significant investment, both hubs have acquired high-end robotic platforms for synthesis, characterization, and testing of a large number of molecular and solid catalysts. The platforms are accompanied by a fully digitalized experimental workflow and a specific data management strategy to support closed-loop experimentation and advanced computational data analysis.
Article
Chemistry, Multidisciplinary
Seraphine B. X. Y. Zhang, Christophe Coperet
Summary: Non-oxidative coupling of methane (NOCM) is a highly researched reaction that is hindered by harsh reaction conditions and limited catalyst stability. Recent studies have highlighted the importance of catalyst nature and reaction conditions, with metal carbides playing a key role in the incorporation of carbidic carbon. This perspective provides an overview of proposed mechanistic pathways and considerations for experiment conditions, aiming to facilitate a rational catalyst design platform for NOCM.
Article
Chemistry, Multidisciplinary
Weicheng Cao, Alexander Yakimov, Xudong Qian, Jiongzhao Li, Xiaogang Peng, Xueqian Kong, Christophe Coperet
Summary: A strategy based on detecting NMR signatures of 113Cd, 77Se, and 15N augmented with DFT modeling was developed to investigate the interaction between amine ligands and CdSe nanocrystals (NCs). The results showed that amine ligands not only directly bond to surface sites, but also interact through hydrogen bonding with absorbed water. This study provides molecular-level insight into the surface properties of amine-capped CdSe NCs and lays the foundation for designing colloidal NCs with tailored properties.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Daniel F. Abbott, Yuan-Zi Xu, Denis A. Kuznetsov, Priyank Kumar, Christoph R. Mueller, Alexey Fedorov, Victor Mougel
Summary: In this study, the catalytic activity of a Fe-substituted two-dimensional molybdenum carbide in nitrate reduction reaction (NO3RR) was investigated. The results showed that the catalyst exhibited high efficiency in both acidic and neutral media. The formation of surface oxygen vacancies promoted by Fe sites was identified as the active sites for NO3RR, similar to the mechanism of natural Mo-based nitrate reductase enzymes.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Seraphine B. X. Y. Zhang, Quentin Pessemesse, Zachariah J. Berkson, Alexander P. Van Bavel, Andrew D. Horton, Pierre-Adrien Payard, Christophe Coperet
Summary: Li/MgO is a prototypical material for oxidative coupling of methane (OCM) with high C-2 selectivity. This study demonstrates that Li/MgO is also an effective catalyst for non-oxidative coupling of methane (NOCM). The presence of Li favors the formation of magnesium acetylide (MgC2), which promotes C-C bond formation and enhances C-2 selectivity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Zixuan Chen, Nora K. Zimmerli, Muhammad Zubair, Alexander V. Yakimov, Snaedis Bjorgvinsdottir, Nicholas Alaniva, Elena Willinger, Alexander B. Barnes, Nicholas M. Bedford, Christophe Coperet, Pierre Florian, Paula M. Abdala, Alexey Fedorov, Christoph R. Mueller
Summary: Gallia-based shells with varying thickness were prepared using atomic layer deposition (ALD) and their atomic-scale structure was studied. The abundance and strength of Lewis acid sites and Bronsted acid sites in the shells were found to correlate with the catalytic performance. This provides insights for the rational design of active Ga-based catalysts.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Moritz Bernhardt, Lukas Latsch, Boris Le Guennic, Christophe Coperet
Summary: This work models surface sites with ten neutral complexes and investigates their potential as single-molecule magnets. The results show that the spatial position of the anionic ligands significantly influences the magnetic properties, while the neutral ligands have a minor role.
HELVETICA CHIMICA ACTA
(2023)
Article
Chemistry, Multidisciplinary
Hui Zhou, Scott R. Docherty, Nat Phongprueksathat, Zixuan Chen, Andrey V. Bukhtiyarov, Igor P. Prosvirin, Olga V. Safonova, Atsushi Urakawa, Christophe Coperet, Christoph R. Muller, Alexey Fedorov
Summary: A Cu-Zn/SiO2 catalyst was developed for the efficient and selective hydrogenation of CO2 to methanol. The optimized catalyst exhibited an intrinsic methanol formation rate of 4.3 g h(-1) g(Cu) (-1) and a selectivity to methanol of 83% at 230 degrees C and 25 bar.
Article
Chemistry, Multidisciplinary
Lukas Rochlitz, Jorg W. A. Fischer, Quentin Pessemesse, Adam H. Clark, Anton Ashuiev, Daniel Klose, Pierre-Adrien Payard, Gunnar Jeschke, Christophe Coperet
Summary: This study investigates the effect of Ti doping on the catalytic performance of Pt and PtZn materials in propane dehydrogenation. The results show that Ti-doping significantly changes the electronic structure of nanoparticles and improves the stability of the materials.
Article
Chemistry, Multidisciplinary
Christian Ehinger, Xiaoyu Zhou, Max Candrian, Scott R. Docherty, Stephan Pollitt, Christophe Coperet
Summary: The synthesis of well-defined materials as model systems for catalysis and related fields plays a crucial role in understanding catalytic processes at a molecular level. Organometallic precursors have been developed to produce monodispersed supported nanoparticles, nanocrystals, and films. A new family of precursors based on group 10 metals has been discovered, which can generate small and monodispersed nanoparticles on metal oxides. These precursors show potential for synthesizing bimetallic catalyst materials and have been demonstrated for hydrogenation of CO2 to methanol.
Article
Chemistry, Multidisciplinary
Seraphine B. X. Y. Zhang, Quentin Pessemesse, Lukas Latsch, Konstantin M. Engel, Wendelin J. Stark, Alexander P. van Bavel, Andrew D. Horton, Pierre-Adrien Payard, Christophe Coperet
Summary: Transition metal carbides, such as Mo and W carbides, exhibit excellent properties in terms of hardness, thermal stability, and conductivity, making them popular in catalytic applications. This study reveals the active involvement of carbidic carbon in the formation of C-2 products during methane coupling at high temperature, highlighting the importance of carbon diffusivity and exchange capability on catalyst performance. Mo carbide (Mo2C) shows stable C-2 selectivity over time due to fast carbon diffusion dynamics, while W carbide (WC) exhibits loss of selectivity due to slow diffusion. Overall, this study provides evidence for a Mars-Van Krevelen type mechanism in the non-oxidative coupling of methane.
Article
Chemistry, Multidisciplinary
Xiaoyu Zhou, Gregory A. Price, Glenn J. Sunley, Christophe Coperet
Summary: This study synthesized cobalt nanoparticles with different sizes through surface organometallic chemistry and found that under CO2 hydrogenation conditions, smaller particles mainly catalyzed the reverse water-gas shift reaction, while larger particles were more favorable for methanation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
