Article
Chemistry, Physical
Abdalla Hroub, Mohamad Hasan Aleinawi, Maria Stefan, Maria Mihet, Alexandra Ciorita, Feray Bakan-Misirlioglu, Emre Erdem, Arpad Mihai Rostas
Summary: In this study, vanadium (V)-doped MgO nanoparticles were used as electrode materials in all-in-one solid-state supercapacitors. The structural and morphological properties of the prepared samples were thoroughly analyzed using various techniques. The results showed that the V-doped MgO material displayed excellent capacitance performance and a maximum energy density of 4.17 Wh/kg. The addition of booster material like carbon black further enhanced the specific capacitance value to 1200 F/g, a value never reported before for MgO-based materials.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
Valeria Lagostina, Eleonora Romeo, Anna Maria Ferrari, Valter Maurino, Mario Chiesa
Summary: Metal atoms and ions on well-defined anatase TiO2 crystals exhibit promising potential as a platform for fundamental studies in catalysis. The geometric and electronic structures of supported paramagnetic vanadium catalysts were investigated, revealing the influence of TiO2 surface termination on the molecular structures of the catalysts. These findings contribute to the development of novel catalytic systems with higher activities.
JOURNAL OF CATALYSIS
(2022)
Review
Chemistry, Multidisciplinary
Xiaoju Yang, Bingjun Xu, Jingguang G. Chen, Xuan Yang
Summary: Distributed electrochemical nitrogen reduction reaction (ENRR) powered by renewable energy for the on-site production of ammonia is an attractive alternative to the industrial Haber-Bosch process, which is responsible for roughly 2 % of global energy consumption. In this Review, we summarize recent progress in the ENRR catalyzed by transition metal nitrides (TMNs). The unique electronic structures of TMNs make them promising ENRR catalysts for active and selective ammonia production, which have been predicted theoretically and demonstrated experimentally. Reaction pathways and deactivation mechanisms of the ENRR on different TMNs are surveyed, and current understanding of structure-activity relations is discussed. To develop highly active, selective, and stable TMN catalysts for industrial-scale ENRR, membrane electrode assembly configuration is recommended in catalyst evaluation. Furthermore, we highlight the importance of developing mechanistic understanding on ENRR with different operando spectroscopic techniques.
Article
Chemistry, Physical
Stefanie Wesinger, Matthias Mendt, Jakob Albert
Summary: Alcoholic solvents, especially methanol, activate heteropolyacids in homogeneously catalyzing glucose transformation reactions, resulting in high carbon efficiency. Through spectroscopic tools, it has been proven that the complex in methanolic solution plays a key role in the selectivity shift of the transformation reaction.
Article
Chemistry, Physical
Carola S. Seelmann, Simona G. Huwiler, Martin Culka, Marc J. F. Strampraad, Till Biskup, Stefan Weber, G. Matthias Ullmann, Volker Schunemann, Peter-Leon Hagedoorn, Antonio J. Pierik, Matthias Boll
Summary: In anaerobic aromatic compound degrading microbes, class II benzoyl-coenzyme A (CoA) reductases (BCRs) reduce benzoyl-CoA to cyclohexa-1,5-diene-1-carboxyl-CoA (1,5-dienoyl-CoA) through a tungsten-bis-metallopterin (MPT) cofactor. This study provides experimental evidence for the Birch-like reduction mechanism via W(V)/radical intermediates and reveals the unique tetrahydro state of MPT cofactors essential for the reversibility of enzymatic Birch reduction.
Article
Chemistry, Multidisciplinary
Shuangshuang Tan, Yuhang Dai, Yalong Jiang, Qiulong Wei, Guobin Zhang, Fangyu Xiong, Xingqi Zhu, Zhi-Yi Hu, Liang Zhou, Yongcheng Jin, Kiyoshi Kanamura, Qinyou An, Liqiang Mai
Summary: Metal nitrides and quasi-metallic compounds are widely used as sulfur hosts in Lithium-sulfur batteries to enhance electronic conductivity and trap polysulfide shuttling. The surface compositions and sulfur anchoring mechanisms of these materials remain controversial. This study elucidates the anion-substituted mechanism in vanadium oxynitride and nitride, revealing the enhanced electron delocalization and catalytic properties for promoting the development of advanced cathode materials.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Nannan Wang, Jing Li, Jinpei Hei, Xiaodong Chen, Xiaojie Yin, Yang Han, Mingling Li, Lifeng Cui
Summary: Defect engineering is crucial for electrocatalysts, especially for ultrathin nanosheets of transitional metal compounds with high surface to bulk ratio that can be engineered along the grain boundaries. In this study, we developed super-thin and ordered face-centered cubic VN nanosheets with grain boundaries using a facile and in-situ method. The prepared samples showed significant temperature-dependent sheet distribution, and the thickness of the nanosheets was found to be crucial for electrochemical reactions. The VN nanosheets demonstrated interesting oxygen reduction reaction performance with high onset potential and durability, highlighting the importance of surface engineering in electrocatalyst performance for potential practical applications.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Philipp Lenz, Ryo Oshimizu, Sina Klabunde, Constantin G. Daniliuc, Christian Mueck-Lichtenfeld, Jonas C. Tendyck, Tatsuya Mori, Werner Uhl, Michael Ryan Hansen, Hellmut Eckert, Shigehiro Yamaguchi, Armido Studer
Summary: This article presents a new type of oxy-borylenes as photoreductants. Experimental results demonstrate that these oxy-borylenes can exhibit strong reducing capability under visible light, making them suitable for various reactions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Svetlana Kucher, Christina Elsner, Mariya Safonova, Stefano Maffini, Enrica Bordignon
Summary: The study demonstrates the feasibility of using double electron-electron resonance (DEER) technique to measure distances between protein sites at very low protein concentrations, providing a new approach for studying conformational changes of biomolecules.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Mehrafshan G. Jafari, Yerin Park, Bimal Pudasaini, Takashi Kurogi, Patrick J. Carroll, David M. Kaphan, Jeremy Kropf, Massimiliano Delferro, Mu-Hyun Baik, Daniel J. Mindiola
Summary: This study presents the synthesis of a novel vanadium complex, investigating its electronic ground state using computational and experimental methods. The research reveals the mechanism of P-atom transfer and the nature of the low-valent vanadium ion in the complexes 2 and 4.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Engineering, Mechanical
Kylie E. Van Meter, Md Istiaque Chowdhury, Mark J. Sowa, Alexander C. Kozen, Tomas Grejtak, Tomas F. Babuska, Nicholas C. Strandwitz, Brandon A. Krick
Summary: This study investigates the influence of deposition temperature on the wear behavior and material properties of plasma enhanced atomic layer deposited (PEALD) TiVN films. The wear rates of the TiVN films varied with deposition temperature, with the 250°C sample achieving ultralow wear. The PEALD TiVN films exhibited low wear and friction properties, low electrical resistivity, and high density and crystallinity.
Article
Chemistry, Multidisciplinary
Huowang He, Zongren Ye, Daiki Shimizu, Idrees Sumra, Yihuan Zhang, Zhengyu Liang, Yingyu Zeng, Ling Xu, Atsuhiro Osuka, Zhuofeng Ke, Hua-Wei Jiang
Summary: This study reported the synthesis, characterization, and reactivities of two stable Ni-III N-confused porphyrin (NCP) complexes. The role of the 3-ethoxy group in the formation of Ni-III NCP complexes was highlighted in comparative experiments. The structures of the complexes were determined by single-crystal X-ray diffraction analysis, and the paramagnetic nature of the Ni-III complexes was confirmed by EPR spectra.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Crystallography
Tao Zhang, Wang Zhou, Yuanyuan Li, Qian Ye, Xiaowen Yu, Zhao Chen
Summary: This paper investigates the effects of CaO on the phase evolution mechanism of vanadium slag in the processes of slagging, direct roasting, and (NH4)(2)CO3 leaching. The results show that with increasing CaO content, vanadium is concentrated in spinels, titanium is transformed into CaTiO3, and phosphorus is concentrated and transformed into different compounds. In the direct roasting process, some vanadium phases react with Ca2SiO4 to produce soluble calcium vanadate, while others decompose into insoluble vanadium oxides. Additionally, (NH4)(2)CO3 leaching solution can inhibit the leaching of certain compounds in the vanadium slag.
Article
Chemistry, Multidisciplinary
Arianna Actis, Michele Melchionna, Giacomo Filippini, Paolo Fornasiero, Maurizio Prato, Enrico Salvadori, Mario Chiesa
Summary: This study assesses the influence of morphology and light-excitation on the number and chemical nature of radical defects in carbon nitride (CN) and derives the spatial distribution of native radicals in CN using magnetic dipole-dipole coupling.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Yujie Ma, Xue Han, Shaojun Xu, Zi Wang, Weiyao Li, Ivan da Silva, Sarayute Chansai, Daniel Lee, Yichao Zou, Marek Nikiel, Pascal Manuel, Alena M. Sheveleva, Floriana Tuna, Eric J. L. McInnes, Yongqiang Cheng, Svemir Rudic, Anibal J. Ramirez-Cuesta, Sarah J. Haigh, Christopher Hardacre, Martin Schroder, Sihai Yang
Summary: Metal-organic framework materials provide an excellent platform for fabricating single-atom catalysts, and this study focuses on atomically dispersed copper sites in UiO-66 for catalytic reduction of NO2. Various characterization techniques confirm the atomic dispersion of copper sites and their significant role in the catalytic process, leading to superior catalytic performance without the need for reductants.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Johannes Nebauer, Christian Neiss, Marcel Krug, Alexander Vogel, Dominik Fehn, Shuhei Ozaki, Frank Rominger, Karsten Meyer, Kenji Kamada, Dirk M. Guldi, Andreas Goerling, Milan Kivala
Summary: This article describes a new type of nitrogen-centered polycyclic scaffold synthesized through intramolecular oxidative cyclodehydrogenation of tri(1-naphthyl)amine, which is the first example of a direct 3-fold cyclization of a triarylamine under oxidative conditions. Experimental and theoretical studies reveal the impact of cyclization on the electronic and photophysical properties, and mechanistic studies suggest the cyclization occurs under kinetic control via a dicationic mechanism.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Energy & Fuels
Chirag Mevawala, Tom Autrey, Kriston Brooks, Mark Bowden, Ba L. Tran, Karsten Muller
Summary: Hydrogen storage is a crucial technology for future decarbonized energy systems, and chemical conversion to a liquid hydrogen carrier can address the challenge of low volumetric density in compressed hydrogen. The thermodynamics of the reversible reaction of 1,4-butanediol (BDO) to gamma-butyrolactone, which releases hydrogen, are evaluated. The analysis shows that the energy efficiency of both liquid-phase and gas-phase reactions is similar, allowing selection of reaction conditions based on catalytic considerations.
Article
Chemistry, Inorganic & Nuclear
Yafei Gao, Wei-Tsung Lee, Veronica Carta, Chun-Hsing Chen, Joshua Telser, Jeremy M. M. Smith
Summary: The reduction of cobalt(II) chloride complex, Ph2B((t)BuIm)(2)Co(THF)Cl (1) with (BuN)-Bu-t equivalent to C produces the diamagnetic, square planar cobalt(I) complex Ph2B((t)BuIm)(2)Co(C equivalent to(NBu)-Bu-t)(2) (2). Complex 2, with its 16-electron configuration, is structurally related to square planar noble metal complexes. Oxidation of complex 2 results in its cobalt(II) analogue [Ph2B((t)BuIm)(2)Co(C=(NBu)-Bu-t)(2)]BPh4 (3-BPh4), which exhibits low-spin d(7) with an unpaired electron in a d(z)(2) orbital, consistent with DFT calculations. Despite its 16-electron configuration and the d(z)(2) parentage of the HOMO, complex 2 undergoes only one-electron oxidation to form complex 3.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Ba L. Tran, Jeremy D. Erickson, Amy L. Speelman, R. Morris Bullock
Summary: The ability of Cu-H complexes to selectively insert unsaturated hydrocarbons has made them valuable catalysts. The formation of Cu allyl intermediates from 1,3-dienes and Cu hydrides is a promising strategy. However, there is limited research on the mechanistic studies and characterization of intermediates in Cu-H catalysis. This study explores the steric effects of NHC ligands on two key elementary steps of CuH-catalyzed carbonyl allylation and provides insights for a range of catalytic reactions.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Martin Keilwerth, Weiqing Mao, Sergio A. V. Jannuzzi, Liam Grunwald, Frank W. Heinemann, Andreas Scheurer, Joerg Sutter, Serena DeBeer, Dominik Munz, Karsten Meyer
Summary: Terminal imido complexes of iron have been widely studied in metal-catalyzed nitrogen-transfer chemistry. In this study, a new tris-NHC chelating ligand (TIMMNMes) was used to synthesize and compare two series of iron alkyl imido complexes, including a reactive Fe(V) adamantyl imido intermediate. The stability and reactivity of these complexes were investigated using various characterization techniques and quantum chemical calculations.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Evan A. Patrick, Mark E. Bowden, Jeremy D. Erickson, R. Morris Bullock, Ba L. Tran
Summary: Mechanistic studies have shown that substrate insertion into dimeric [(NHC)CuH](2) complexes requires dimer dissociation. However, using single-crystal to single-crystal transformations, a new pathway of stepwise CO2 insertion into [(NHC)CuH](2) without complete dissociation of the dimer was discovered. This approach led to the formation of dicopper formate complexes which are inaccessible through solution reactions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Review
Chemistry, Multidisciplinary
Judith Riedhammer, Dominik P. Halter, Karsten Meyer
Summary: This review provides a comprehensive summary of electrochemistry data reported on uranium complexes in nonaqueous electrolyte, serving as a reference for newly synthesized compounds and evaluating the influence of different ligand environments on electrochemical properties. The data for over 200 uranium compounds are reported, along with a discussion on trends observed across complexes in response to ligand field variations. The newly derived uranium-specific ligand field parameters are shown to be useful for predicting structure-reactivity correlations and activating specific substrate targets.
Article
Chemistry, Inorganic & Nuclear
Laxmi Devkota, Daniel J. SantaLucia, Amelia M. Wheaton, Alexander J. Pienkos, Sergey V. Lindeman, J. Krzystek, Mykhaylo Ozerov, John F. Berry, Joshua Telser, Adam T. Fiedler
Summary: The observation of single-molecule magnetism in transition-metal complexes relies on the phenomenon of zero-field splitting, which arises from the interplay of spin-orbit coupling with ligand-field-induced symmetry lowering. The heavy-atom effect in high-spin cobalt(II)-halide complexes was systematically studied in this study, where the magnitude of zero-field splitting was investigated through various techniques. The role of molecular geometry, ligand-field effects, and metal-ligand covalency in controlling the magnitude of zero-field splitting in cobalt-halide complexes was revealed through interpretation of the magnetic parameters.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Douglas R. Hartline, Sascha T. Loeftier, Dominik Fehn, Joseph M. Kasper, Frank W. Heinemann, Ping Yang, Enrique R. Batista, Karsten Meyer
Summary: In this study, the cleavage of the O-O bond of an organic peroxide mediated by a uranium complex was investigated. This reaction proceeds via an isolable diuranium(IV/IV) intermediate and generates a stable uranium(V) bis-alkoxide complex. The significance of this research lies in the development of a new method for uranium-catalyzed O-O bond cleavage.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Weiqing Mao, Zihan Zhang, Dominik Fehn, Sergio A. V. Jannuzzi, Frank W. Heinemann, Andreas Scheurer, Maurice van Gastel, Serena DeBeer, Dominik Munz, Karsten Meyer
Summary: This study describes the synthesis, characterization, and reactivity of a series of cobalt terminal imido complexes supported by an N-anchored tripodal tris(carbene) chelate. The complexes were fully characterized using various spectroscopic and crystallographic techniques. Quantum chemical calculations provided insight into the electronic structures of the compounds. The findings highlight the reactivity of these cobalt imido complexes, including their ability to undergo intramolecular C-H bond amination and nucleophilic addition reactions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Andrea Squarcina, Dominik Fehn, Andreas Scheitler, Laura Senft, Alicja Franke, Achim Zahl, Ralph Puchta, Karsten Meyer, Ivana Ivanovic-Burmazovic
Summary: The most active dual superoxide dismutase (SOD) and catalase (CAT) functional analogue, the dinuclear Mn-2(II,II)L-2-core, was investigated for its catalytic O-2 (center dot-) decomposition mechanism. Two stereoisomers were studied to determine their SOD activity, characterize the intermediates involved, and differentiate between single- and di-Mn center catalysis. Structural characterization, quantum chemical analysis, and various analytical techniques supported the conclusions drawn from this study. The effects of the Mn-2(II,II)-core configuration on the SOD activity were discussed.
Article
Chemistry, Multidisciplinary
Soosan Hosseinmardi, Andreas Scheurer, Frank W. Heinemann, Nicola Marigo, Dominik Munz, Karsten Meyer
Summary: This study reports a two-step protonation reaction from a Ni-0 precursor to dihydrogen, with the formation of a rare nickel dihydrogen complex in the second protonation step.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Wowa Stroek, Martin Keilwerth, Lorraine A. Malaspina, Simon Grabowsky, Karsten Meyer, Martin Albrecht
Summary: Catalytic C-N bond formation by direct activation of C-H bonds offers wide synthetic potential. This study reports the synthesis of a stable iron alpha-N coordinated organoazide complex and reveals its reaction mechanism in solution.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Inorganic & Nuclear
Robert J. Ortiz, Michael Shepit, Johan van Lierop, J. Krzystek, Joshua Telser, David E. Herbert
Summary: The ligand fields of Ni(II) complexes supported by diarylamido pincer-type amido ligands were investigated. The ligand field parameters were determined using HFEPR, SQUID magnetometry, and electronic absorption spectroscopy. The ability to electrochemically address ligand-based oxidations and the presence of electronic communication between N-amido moieties were also studied.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Jacob S. Mohar, Anders Reinholdt, Taylor M. Keller, Patrick J. Carroll, Joshua Telser, Daniel J. Mindiola
Summary: We report the synthesis of the first mononuclear Ti-III complex with a terminal imido ligand. This complex was prepared through reduction of [Tp(tBu,Me)Ti{=NSi(CH3)(3)}(Cl)] with KC8, and its connectivity and metalloradical nature were confirmed by various spectroscopic techniques. Electrochemical studies showed a reversible 1e(-) process for the complex, and chemical oxidants reacted cleanly with it to produce other derivatives.
CHEMICAL COMMUNICATIONS
(2023)
