Article
Chemistry, Physical
Benginur Demir, Thomas Kropp, Elise B. Gilcher, Manos Mavrikakis, James A. Dumesic
Summary: The study utilized a combination of reaction kinetics measurements, electronic structure calculations, and microkinetic modeling to investigate the effects of water on metal catalyst surfaces in the hydrogenation of oxygenates. Results showed that water enhances hydrogenation rates on oxophilic metal catalysts like Ru/C, but not on Pt-based catalysts. Microkinetic modeling predicted the favored reaction pathway and species coverage on Ru surfaces, aiding in understanding the mechanistic role of water in the metal catalyzed reactions for producing chemical building blocks from biomass-derived oxygenates.
JOURNAL OF CATALYSIS
(2021)
Article
Chemistry, Inorganic & Nuclear
Margarita Ruiz-Castaneda, Lucia Santos, Blanca R. Manzano, Gustavo Espino, Felix A. Jalon
Summary: Deuterium labeling is a process that leads to compounds useful in various fields, with the transfer hydrogenation of aldehydes and selective deuteration of alcohols described in this study. The use of a biphasic water/toluene system was found to enable higher yields and selective D incorporation. Additionally, efficient M-H/D+ exchange from D2O was found to play a key role in the deuteration process.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2021)
Article
Biochemistry & Molecular Biology
Amanda L. Kwan, Robert H. Morris
Summary: This article introduces the largest-scale asymmetric catalytic process for the industrial production of (S)-metolachlor, which is achieved through the hydrogenation of N-(2-ethyl-6-methylphenyl)-1-methoxypropan-2-imine. The authors propose a plausible proton-first, outer-sphere mechanism based on density functional theory calculations that explains the reduction of the sterically hindered bond in the imine.
Article
Chemistry, Physical
Xingtao Wang, Jiangshan Zhao, Yongwang Li, Xubin Zhang, Fumin Wang, Botao Wu, Tian Wang
Summary: Pincer ligand supported Ru-II chloride complexes can be used as non-mercury molecular catalysts for acetylene hydrochlorination. The catalytic mechanism and interaction between catalysts and reactants have been evaluated, indicating that the (pincer)(RuCl2)-Cl-II platform supports electrophilic proton-ruthenation of C2H2. Energy decomposition studies reveal the electron-rich property of the Ru-II center, leading to lower energetic barriers and favoring the electrophilic reaction mechanism. Improving the electron-donating ability of ligands can enhance the lowering of energetic barriers, enabling the design of non-mercury catalysts with milder reaction conditions and higher catalytic activity for acetylene hydrochlorination.
Article
Chemistry, Inorganic & Nuclear
Jeyson Esquivel Curichimba, Roberto Luiz Andrade Haiduke
Summary: In this study, the reaction mechanism of the semi-hydrogenation reaction catalyzed by {(C5H4N)(C6H4)}RuCl(CO)(PPh3)(2) catalyst was evaluated using Density Functional Theory. The calculations revealed the existence of four new intermediates to overcome steric hindrance issues and explained the release of the products. Additionally, the turnover frequency (TOF)-determining transition state (TDTS) and intermediate (TDI) were identified in the first cycle using the energetic span model.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Fang Yong, Junxia Yang, Zhaomin Wei, Lei Zhang, Wenli Yuan, Guohong Tao, Song Qin
Summary: The study investigated the reaction mechanism of Pd-catalyzed ynamide hydrogenation with ethanol as a hydrogenation agent using DFT, revealing a multistep pathway with low energy barriers facilitated by ethanol as a proton shuttle. The high selectivity towards enamine was attributed to the post-transition-state dynamics in the second hydrogenation stage, with E-configuration as the predominant product, consistent with experimental observations.
JOURNAL OF ORGANOMETALLIC CHEMISTRY
(2021)
Article
Chemistry, Physical
Morad M. El-Hendawy, Abd El-Motaleb M. Ramadan, Mohamed M. Ibrahim
Summary: The study investigated the catalytic hydrogenation of cyclohexene by a newly synthesized ruthenium(III) Schiff base complex using various physicochemical methods. It was found that the catalytic activity depends mainly on solvent composition. Density functional theory was applied to explore the mechanistic story of the catalytic reaction.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Chemistry, Inorganic & Nuclear
Peter Pal Feher, Ferenc Joo, Gabor Papp, Mihaly Purgel
Summary: This study investigates the catalytic role of trans-dihydride complexes and provides insight into the feasibility of water-soluble ruthenium trans-dihydride complexes as catalytic species. By considering thermodynamically accessible trans-dihydrides, two viable competing reaction channels were identified, with the inclusion of explicit solvent molecules playing a key role in determining selectivity.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Yong Wu, Shanshan Cao, Iskander Douair, Laurent Maron, Xihe Bi
Summary: The [2+1] cycloaddition reaction of a metal carbene with an alkene often suffers from side reactions, leading to lower yields of cyclopropanation products. By adding a low concentration of diazo compound to alkenes, it was found that AgOTf catalysis can efficiently produce cyclopropane products from hindered alkenes.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Frederick P. Malan
Summary: A facile synthesis method was reported for a range of cyclooctadiene Ru(II) complexes with different nitrile ligands, and solid-state characterization was performed for these complexes. The complexes displayed instability in solution, leading to spontaneous dimerization. Varied catalytic activity was observed using these complexes, with the highest activity observed in the transfer hydrogenation of ketones.
Article
Chemistry, Multidisciplinary
Marin Puget, Viacheslav Shcherbakov, Sergey Denisov, Philippe Moreau, Jean-Pierre Dognon, Mehran Mostafavi, Sophie Le Caer
Summary: The nature of the primary species formed in FEC depends on the amount of FEC in the solution, which will affect its performance in the electrolyte.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Physical
Zhiyao Duan, Graeme Henkelman
Summary: This study uses global optimization and constant-potential density functional theory to simulate the complete process of Pt dissolution, revealing the formation and dissolution mechanism of a two-dimensional Pt surface oxide. The findings provide a fundamental understanding of Pt dissolution under potential cycling, which is essential for the rational design of durable Pt-based cathodes for fuel cells.
Article
Chemistry, Multidisciplinary
Lia Sotorrios, Fedor M. Miloserdov, Anne-Frederique Pecharman, John P. Lowe, Stuart A. Macgregor, Mary F. Mahon, Michael K. Whittlesey
Summary: The syntheses, reactivity, and electronic structure analyses of [Ru(PPh3)(2)(ZnMe)(4)H-2] and [Ru(PPh3)(2)(ZnPh)(4)H-2] are reported. [Ru(PPh3)(2)(ZnMe)(4)H-2] exhibits an 8-coordinate Ru center with axial phosphines and a symmetrical (2 : 2) arrangement of ZnMe ligands in the equatorial plane. The ZnMe ligands in [Ru(PPh3)(2)(ZnMe)(4)H-2] undergo facile, sequential exchange with ZnPh2 to give [Ru(PPh3)(2)(ZnPh)(4)H-2], which shows a 3 : 1 arrangement of ZnPh ligands. Mechanisms for ZnMe/ZnPh exchange and isomerization are proposed using DFT calculations, and the relationships of these {Ru(ZnR)(4)H-2} species to isoelectronic Group 8 transition metal polyhydrides and related Schlenk equilibria in the Negishi reaction are discussed.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Raphael Robidas, Claude Y. Legault
Summary: A mechanism is proposed to explain the formation of benzobicyclo[3.2.0]heptane derivatives from 1,7-enyne derivatives bearing a terminal cyclopropane, which has been previously reported.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Organic
Kurt Puntener, Raphael Bigler, Kenta Stier, Marek P. Checinski
Summary: This study investigates the asymmetric hydrogenation of beta-ketoesters catalyzed by [RuCl2(MeOH)(2)((R)-MeOBIPHEP)]. It is found that HCl acts as both an activator and has a significant impact on the reaction. The study also explains the effects of common phosphorus substituents on the activity of the catalyst.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Physical
Amelie A. Ehrhard, Matthias P. Klein, Jennifer Mohrbach, Sebastian Dillinger, Gereon Niedner-Schatteburg
Summary: The study reveals that the adsorption limits of N-2 on Rh-i(+) clusters strongly depend on the cluster size, with some clusters having rough surfaces and others having smooth surfaces. The sequential adsorption of N-2 is found to be the only significant reaction channel, with occasional desorption steps indicating adsorption-desorption equilibria. DFT calculations show that an adsorption induced spin quenching occurs at considerable N-2 coverage on Rh-5(+).
Article
Chemistry, Multidisciplinary
Laura Stein, Pit Boden, Robert Naumann, Christoph Foerster, Gereon Niedner-Schatteburg, Katja Heinze
Summary: Cr(ppy)(3), a structural analog of the green phosphorescent Ir(ppy)(3), emits light even at room temperature in solution from a weakly distorted spin-flip state. The emission intensity is significantly influenced by temperature.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Matthias Tombers, Jennifer Meyer, Jonathan Meyer, Arkadiusz Lawicki, Vicente Zamudio-Bayer, Konstantin Hirsch, J. Tobias Lau, Bernd von Issendorff, Akira Terasaki, Thomas A. Schlathoelter, Ronnie A. Hoekstra, Sebastian Schmidt, Annie K. Powell, Eva Kessler, Marc H. Prosenc, Christoph van Wuellen, Gereon Niedner-Schatteburg
Summary: In this study, the magnetic properties of isolated cationic species [Mn12O12(CH3COO)(15)(CH3CN)](+) were investigated using gas phase X-ray Magnetic Circular Dichroism spectroscopy, and found to resemble closely to that of the corresponding bulk samples. Additionally, broken symmetry DFT calculations revealed that the Mn-4(IV) core exhibits almost no magnetic anisotropy, while the surrounding Mn-8(III) ring is highly anisotropic. These intrinsic magnetic properties are largely unaffected by environmental factors, suggesting robustness in the Mn-12 core scaffold within these complexes.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Physical
Amelie A. Ehrhard, Matthias P. Klein, Jennifer Mohrbach, Sebastian Dillinger, Gereon Niedner-Schatteburg
Summary: The study reports the N-2 cryo adsorption kinetics of selected gas phase mixed rhodium-iron clusters in a 26 K helium buffer gas, revealing significant trends in adsorption behavior, equilibrium reactions, and limits. The calculated sticking probabilities increase with cluster size and decrease with N-2 adsorption level when reaching equilibrium. Evidence on cluster size dependent properties is obtained through spectroscopic and computational studies on equiatomic clusters.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Matthias P. Klein, Amelie A. Ehrhard, Maximilian E. Huber, Annika Strassner, Daniela V. Fries, Sebastian Dillinger, Jennifer Mohrbach, Gereon Niedner-Schatteburg
Summary: In this study, the N-2 adsorption behavior of bimetallic rhodium-iron cluster cations [RhiFej(N-2)(m)](+) was investigated using InfraRed MultiplePhotoDissociation (IR-MPD) spectroscopy and density functional theory (DFT) modeling. The results showed preferential adsorption of N-2 to Rh sites and secondary adsorption to Fe sites. Adsorption isomers were also observed, and the position of IR bands allowed for element specific assignment of adsorption sites. Unlike previous studies, no spin quenching was observed during N-2 adsorption in [RhiFej(N-2)(m)](+) clusters.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Inorganic & Nuclear
Christian Malchau, Daniela Fries, Yannick Mees, Marisa F. Jakobs, Yu Sun, Sabine Becker, Gereon Niedner-Schatteburg, Werner R. Thiel
Summary: Starting from [(eta(5)-cyclopentadienyl)(eta(6)-phenyl)iron(II)]imidazole, dicationic imidazolium salts were prepared by N-alkylation, and mono respectively dicationic transition metal NHC complexes were obtained. Transmetalation using the copper(I) complexes opened up the access to NHC gold(I) compounds. The new NHC complexes were investigated by various analytical methods, and their catalytic properties were tested in different model reactions.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Physical
Masahiro Shibuta, Maximilian Huber, Toshiaki Kamoshida, Kazuya Terasaka, Miho Hatanaka, Gereon Niedner-Schatteburg, Atsushi Nakajima
Summary: This study examines the chemical stability of metal-encapsulating silicon cage nanoclusters and their superatomic nature on a C-60 substrate. The results show that Ta@Si-16 clusters exhibit the highest stability, and Ta@Si-17 clusters have enhanced stability due to their connection with Si atoms on the substrate.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Medicinal
Sean P. Henry, Maria-Elena Liosi, Joseph A. Ippolito, Fabian Menges, Ana S. Newton, Joseph Schlessinger, William L. Jorgensen
Summary: This study reports the development of probe molecules that can covalently modify the JAK2 pseudokinase domain (JH2). The researchers aimed to selectively target the JH2 domains over the kinase domains (JH1) as potential therapeutic targets. They found that the JH2 domains of JAK1, JAK2, and TYK2 have a cysteine residue in the catalytic loop that is not present in their JH1 domains. By attaching substituents terminating in acrylamide warheads to modify Cys675 of JAK2 JH2, the researchers successfully achieved covalent attachment. The binding selectivity of the JAK2 JH2 domain over the JH1 domain increased by approximately 30-fold after a 20-hour incubation.
ACS MEDICINAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Chungseok Choi, Fengyi Zhao, James L. Hart, Yuanzuo Gao, Fabian Menges, Conor L. Rooney, Nia J. Harmon, Bo Shang, Zihao Xu, Sa Suo, Quynh Sam, Judy J. Cha, Tianquan Lian, Hailiang Wang
Summary: We present a ternary hybrid photocatalyst architecture that enhances the utilization of solar energy for CO2 reduction by synergizing electron and heat flows. The architecture consists of cobalt phthalocyanine (CoPc) molecules assembled on multiwalled carbon nanotubes (CNTs) decorated with nearly monodispersed cadmium sulfide quantum dots (CdS QDs). The CdS QDs absorb visible light and generate electron-hole pairs, which are rapidly transferred from CdS to CoPc by CNTs. The CoPc molecules selectively reduce CO2 to CO. The interfacial dynamics and catalytic behavior are revealed by time-resolved and in situ vibrational spectroscopies. Additionally, the CNT component can create local photothermal heating to activate amine-captured CO2 for direct photochemical conversion without extra energy input.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Raphael I. I. Petrikat, Sophie T. T. Steiger, Elham Barani, Pit J. J. Boden, Maximilian E. E. Huber, Mark R. R. Ringenberg, Gereon Niedner-Schatteburg, Karin Fink, Sabine Becker
Summary: In this report, the structure of the dinuclear copper(II) dimethylglyoxime complex is presented, which undergoes a cooperativity-driven hydrolysis. The Lewis acidity of the copper centers increases the electrophilicity of the carbon atom in the bridging group of dimethylglyoxime, facilitating nucleophilic attack by water. Depending on the solvent, different oxidation and reduction reactions occur, leading to the formation of different products. Synthetic, theoretical, spectroscopic, and spectrometric methods were used to establish the reaction pathway of this solvent-dependent reaction.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Inorganic & Nuclear
Tobias Bens, Daniel Marhoefer, Pit Boden, Sophie T. Steiger, Lisa Suntrup, Gereon Niedner-Schatteburg, Biprajit Sarkar
Summary: This study explores the influence of constitutional isomers of pyridyl-1,2,3-triazolylidene mesoionic carbene (MIC) ligands on the photophysical and photochemical properties of tetracarbonyl group 6 metal complexes (M = Cr, Mo, W). The results show that the increased electron density induced by the C-C linked pyridyl-MIC ligand leads to an increased kinetic rate constant for the reformation of the starting species and lower photodissociation quantum yields.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Daniela V. Fries, Matthias P. Klein, Annika Strassner, Maximilian E. Huber, Gereon Niedner-Schatteburg
Summary: In this study, the researchers conducted an IR-PD investigation of tantalum cluster adsorbate complexes. They observed an increase in spectral complexity and redward inhomogeneous broadening during the loading of N-2 molecules. The larger tantalum clusters showed a lack of spontaneous cleavage of N-2, in contrast to the smaller clusters. The study also found that the adsorption capacity of the tantalum clusters remained constant within a certain range of cluster sizes.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Daniela V. Fries, Matthias P. Klein, Annika Strassner, Maximilian E. Huber, Maximilian Luczak, Christopher Wiehn, Gereon Niedner-Schatteburg
Summary: This study investigates the ability of small tantalum clusters to spontaneously cleave N-2 adsorption under cryogenic conditions. Experimental and quantum chemical simulations reveal that all tantalum clusters can efficiently cleave N-2. The study of the tantalum trimer Ta-3 uncovers the reaction paths for cleaving the first and activating the second and third N-2 molecules, and identifies the intermediates involved. The study of the tantalum tetramer Ta-4 elucidates different N-2 coordination modes, adsorption limits, and the formation and desorption of nitrides.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Winald R. Kitzmann, Maria-Sophie Bertrams, Pit Boden, Alexander C. Fischer, Renei Klauer, Johannes Sutter, Robert Naumann, Christoph Foerster, Gereon Niedner-Schatteburg, Nicolas H. Bings, Johannes Hunger, Christoph Kerzig, Katja Heinze
Summary: Photoactive complexes with earth-abundant metals have been synthesized using cheap metals and simple ligands, showing intense deep-red phosphorescence and long excited state lifetimes. The lack of labilized Mo-CO bonds in the complex results in high photostability. This research provides a promising design strategy for the synthesis of stable photoactive complexes of nonprecious metals.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Pit Boden, Patrick Di Martino-Fumo, Gereon Niedner-Schatteburg, Wolfram Seidel, Katja Heinze, Markus Gerhards
Summary: The research on photoactive transition metal complexes is rapidly growing, with a focus on understanding the underlying photophysical processes. Luminescent chromium(iii) complex exhibits stronger luminescence at lower temperatures due to decreased non-radiative decay and increased radiative decay. Further studies on transition metal complexes with similar excited states are important for future advancements.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)