Article
Chemistry, Multidisciplinary
Albert Th Thorhallsson, Ragnar Bjornsson
Summary: This study explores the energy surface of the E-2 state of FeMoco and identifies two possible contender models: one containing a bridging hydride and an open sulfide-bridge (hydride model), and the other featuring a protonated belt-sulfide and a reduced cofactor without a hydride (non-hydride model).
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Review
Physics, Multidisciplinary
Ladislav Havela, Dominik Legut, Jindrich Kolorenc
Summary: This article discusses the hydrides of actinides and their magnetic, electronic, transport, and thermodynamic properties. The impact of hydrogen on bonding is characterized by volume expansion, affecting the 5f states, and a charge transfer towards H, which influences the 6d and 7s states. The effects of hydrogenation on actinides vary depending on the localization of their 5f states. Uranium hydrides, UH2 and UH3, exhibit strong magnetism due to narrowing of the 5f band and reduction of the 5f-6d hybridization. Pu hydrides become magnetic by stabilizing the magnetic 5f (5) state and eliminating the non-magnetic 5f (6) component. Ab-initio computational analyses and spectroscopic studies support these findings.
REPORTS ON PROGRESS IN PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Laure Decamps, Derek B. Rice, Serena DeBeer
Summary: This study provides experimental evidence that the cofactor of the iron nitrogenase contains a carbide, making the Fe6C core a common feature among all nitrogenase cofactors.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Biochemistry & Molecular Biology
Oliver Einsle
Summary: Nitrogenase is an essential enzyme for all organismic life, providing bioavailable nitrogen for biomacromolecule synthesis. Recent studies have shown that nitrogenase has structural plasticity with multiple substrate binding sites, and dynamic conformational changes have been observed using cryo-electron microscopy. These findings contribute to a better understanding of the catalytic mechanism of nitrogenase.
CURRENT OPINION IN STRUCTURAL BIOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Christian Knuepfer, Christian Faerber, Jens Langer, Sjoerd Harder
Summary: Alkenes that are normally unreactive with LiAlH4 can be reduced to alkanes by a mixture of LiAlH4 and Fe-0. This reaction does not require the use of water or acids and the H atoms for the reduction come from LiAlH4. The LiAlH4/Fe-0 combination is also an effective catalyst for hydrogenation of multi-substituted alkenes and benzene/toluene.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Jonathan Trouve, Khalil Youssef, Sitthichok Kasemthaveechok, Rafael Gramage-Doria
Summary: Iron catalysts enable Markovnikov-selective reactions, achieving up to 99% selectivity for ketone products from (hetero)aromatic and aliphatic olefins under ambient conditions. The catalyst design, inspired by the promiscuous activity of cytochromes P-450 enzymes, allows the formation of iron-hydride species under catalytically relevant conditions, leading to the desired selectivity.
Article
Multidisciplinary Sciences
Jun Cui, Emil Vinas Bostroem, Mykhaylo Ozerov, Fangliang Wu, Qianni Jiang, Jiun-Haw Chu, Changcun Li, Fucai Liu, Xiaodong Xu, Angel Rubio, Qi Zhang
Summary: The research team observed magnon-induced chiral phonons and chirality selective magnon-phonon hybridization in the antiferromagnet FePSe3, which provides new insights for the development of angular momentum-based hybrid phononic and magnonic devices.
NATURE COMMUNICATIONS
(2023)
Article
Environmental Sciences
Christian Furbo Reeder, Carolin Regina Loscher
Summary: This study explored the diversity of genes involved in N-2 fixation by screening metagenomes and -transcriptomes from different ocean regions, identifying a generally increased diversity compared to previous studies based on the nifH gene. While gene expression of alternative nitrogenases could not be confirmed, diazotrophs harboring the potential for alternative nitrogenases were detected.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Erin S. Grant, Liam T. Hall, Lloyd C. L. Hollenberg, Gawain McColl, David A. Simpson
Summary: In this study, the magnetic properties of ferritin, the primary storage protein in the body, were systematically studied using diamond-based quantum spin relaxometry. An anomalous magnetic behavior was observed at relatively low iron loads due to a morphological change in the iron core of ferritin. The inclusion of this morphological change in a theoretical model was supported by electron microscopy studies and provided evidence for the magnetic consequence of the morphological change.
Article
Chemistry, Multidisciplinary
Andras Kovacs, Laura H. Lewis, Dhanalaksmi Palanisamy, Thibaud Denneulin, Alexander Schwedt, Edward R. D. Scott, Baptiste Gault, Dierk Raabe, Rafal E. Dunin-Borkowski, Michalis Charilaou
Summary: Iron and its alloys have played a crucial role in modern civilization, with metallic meteorites serving as one of the earliest sources of usable iron and offering insights into the history of our solar system. Recent research has identified a previously unknown FeNi nanophase within metallic meteorite NWA 6259, which interacts with other nanoprecipitates to create a complex magnetic state.
Article
Physics, Applied
Gonzalo dos Santos, Robert Meyer, Romina Aparicio, Julien Tranchida, Eduardo M. Bringa, Herbert M. Urbassek
Summary: It has been shown that introducing variable magnetic moments can provide a better description of experimental data for the magnetization of small Fe nanoparticles. By dividing atoms into a surface-near shell and a core with bulk properties, adjustments to both the magnitude of the shell magnetic moment and the exchange interactions are necessary to fairly represent the experimental data.
APPLIED PHYSICS LETTERS
(2021)
Article
Nanoscience & Nanotechnology
Narelle Brack, Michelle J. S. Spencer, Benjamin Mapleback, Andy I. R. Herries, Peter Kappen, Andrew N. Rider
Summary: Graphitic nanoplatelets (GNPs) were treated using an ultrasonicated ozonolysis procedure to produce stable aqueous dispersions for thin film deposition using electrophoretic deposition. Zero valence (ZV) iron nanocubes were then coated onto the thin GNP films using pulsed electrodeposition. The changing magnetic character of the ferromagnetic-graphitic hybrid material was related to the nucleation density and growth of the ZV-iron nanocubes. ZV-iron was adsorbed preferentially at the oxygen sites of the GNPs, displacing oxygen groups in some configurations. Transmission electron microscopy studies confirmed that ZV-iron growth nucleated at the edges of the graphite nanoplatelets, and the magnetism of the hybrid material was affected by the convergent crystalline grain boundaries formed between adjacent ZV-iron nanocubes.
Article
Crystallography
Andre Goetze, Siobhan Christina Stevenson, Thomas Christian Hansen, Holger Kohlmann
Summary: Binary intermetallic compounds, such as FePd3, have attracted attention due to their physical, magnetic, and catalytic properties. In this study, the hydrogenation properties of ordered FePd3 and disordered Fe0.25Pd0.75 were investigated using various in situ methods. The results showed that FePd3 absorbs small amounts of hydrogen at room temperature and follows the Sieverts' law. The [Pd-6] octahedral voids were filled with hydrogen atoms as the hydrogen pressure increased, leading to a decrease in long-range order of Fe and Pd atoms. The magnetic moments of iron atoms in FePd3 exhibited a temperature dependence that was consistent with a 3D Ising or Heisenberg model.
Article
Chemistry, Multidisciplinary
Stephan Muessig, Bjoern Kuttich, Florian Fidler, Daniel Haddad, Susanne Wintzheimer, Tobias Kraus, Karl Mandel
Summary: Controlled agglomeration of superparamagnetic iron oxide nanoparticles can rapidly switch their magnetic properties. Changes in temperature induced reversible switching of magnetic properties, with non-linear correlation between magnetization amplitude and agglomeration degree indicating the impact of agglomerates' size distribution on magnetic properties.
NANOSCALE ADVANCES
(2021)
Article
Materials Science, Multidisciplinary
Evgenia A. Tereshina-Chitrova, Ladislav Havela, Mykhaylo Paukov, Milan Dopita, Lukas Horak, Oleksandra Koloskova, Zbynek Soban, Thomas Gouder, Frank Huber, Alice Seibert
Summary: The thin U-Mo films and their hydrides prepared by reactive sputter deposition from metallic targets exhibit metallic properties with high electrical resistivity. The films show superconductivity and ferromagnetism, with attributes such as strong texture and negative temperature coefficient of resistivity.
MATERIALS CHEMISTRY AND PHYSICS
(2021)
Article
Biochemistry & Molecular Biology
Masato Ishizaka, Minghao Chen, Shun Narai, Yoshikazu Tanaka, Toyoyuki Ose, Masaki Horitani, Min Yao
Summary: Iron-sulfur (Fe-S) clusters play a vital role in enzyme activity. This study focuses on the relationship between the Fe-S cluster type and the catalytic activity of a tRNA-thiolation enzyme (TtuA). The researchers observed that [3Fe-4S]-TtuA spontaneously transforms into [4Fe-4S]-TtuA within minutes to an hour, and [3Fe-4S]-TtuA is highly inactive and unstable. These findings provide insights into the Fe-S cluster type used by the tRNA-thiolation enzyme.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Chemistry, Physical
Hanae Takeda, Kanji Shimba, Masaki Horitani, Tetsunari Kimura, Minoru Kubo, Takashi Nomura, Takehiko Tosha, Yoshitsugu Shiro
Summary: This study demonstrates the trapping of short-lived reaction intermediates of metalloenzymes through the photolysis of a caged compound under cryogenic temperature followed by thermal annealing. This technique is essential for elucidating the mechanism of the reaction catalyzed by metalloenzymes.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Article
Chemistry, Inorganic & Nuclear
Lauren E. Wenger, Nicholas M. Shawver, William W. Brennessel, Brian K. Long, Timothy P. Hanusa
Summary: Organoaluminum complexes with different NHC ligands were synthesized and their structures confirmed. The ability of these complexes to initiate the polymerization of L-lactide was examined, with [AlA '(3)] showing the highest effectiveness.
Correction
Chemistry, Inorganic & Nuclear
Lauren E. Wenger, Nicholas M. Shawver, Ross E. Koby, William W. Brennessel, Brian K. Long, Timothy P. Hanusa
Article
Chemistry, Multidisciplinary
Eric Schreiber, William W. Brennessel, Ellen M. Matson
Summary: This study investigates the electronic structure of a reduced polyoxovanadate-alkoxide cluster with a bridging oxide moiety. The incorporation of bridging oxide sites quenches the cluster-wide electron delocalization in the most reduced state, resulting in a change in regioselectivity of PCET to the cluster surface. Reactivity localized at the bridging oxide site enables reversible storage of a single H-atom equivalent, altering the stoichiometry of PCET. The findings provide insights into the design of functional materials for energy storage and conversion processes.
Article
Chemistry, Inorganic & Nuclear
Aleksa Radovic, Nikki J. Wolford, Hongze Li, William W. Brennessel, Hao Xu, Michael L. Neidig
Summary: This study focuses on the ligand effects on reactivity and in situ iron speciation in the iron-catalyzed amino-oxygenation of olefins using a bisoxazoline ligand. Experimental results reveal that the ligand and solvent have significant influence on the speciation in the precatalytic mixture, leading to the formation of different species that affect the reactivity. The in situ experiments provide evidence for the formation of an iron iminyl radical species and suggest that the functionalized hydroxylamine identity can dictate the reactivity observed in these reactions.
Article
Chemistry, Physical
Maria Camila Aguilera, Achyut Ranjan Gogoi, Wes Lee, Lei Liu, William W. Brennessel, Osvaldo Gutierrez, Michael L. Neidig
Summary: Iron-bisphosphines have been widely studied as highly effective and versatile catalytic systems for cross-coupling reactions. However, the mechanistic features essential for their catalytic performance are still unclear. In this study, the authors investigate the mechanism of enantioselective coupling reactions catalyzed by chiral bisphosphine-iron complexes. By using various techniques, they reveal the key intermediates and their roles in the catalytic cycle. The study provides important insights into the radical initiation, factors contributing to side product generation, and protocol effects for selective cross-coupling methods.
Article
Chemistry, Inorganic & Nuclear
Thompson V. Marinho, Eric Schreiber, Rachel E. Garwick, William W. Brennessel, Ellen M. Matson
Summary: This paper presents the post-synthetic modification of a polyoxovanadate-alkoxide cluster by reacting its cationic form with water, leading to the synthesis of a series of POV-alkoxide clusters with different mu(2)-O2- ligands at the surface. The characterization of the clusters and investigation of their redox properties were conducted using infrared and electronic absorption spectra as well as cyclic voltammetry.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Christopher D. Hastings, Lucy S. X. Huffman, Chandan Kumar Tiwari, Jolaine Galindo Betancourth, William W. Brennessel, Brandon R. Barnett
Summary: In this study, a synthetic method for a tripodal ligand scaffold is reported, which forms a narrow and rigid cavity through a macrocyclization reaction. The resulting coordination complexes exhibit a narrow cavity and an open metal coordination site. It is shown that acetonitrile entry into the cavity is sterically precluded, disrupting anticipated coordination at the intracavity site. A new tripodal ligand system is used to access unsaturated metallates of cobalt(II), nickel(II), and zinc(II).
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Kaycie R. Malyk, Vivek G. Pillai, William W. Brennessel, Roberto Leon Baxin, Elliot S. Silk, Daniel T. Nakamura, C. Rose Kennedy
Summary: Carboxylic acid derivatives are attractive alternatives to organohalides for cross-coupling electrophiles in fine chemical synthesis. Carboxamides, in particular, have shown promise as versatile electrophiles for nickel-catalyzed coupling reactions. However, the high catalyst loadings and specific substitution patterns required have limited their applications.
Article
Chemistry, Inorganic & Nuclear
Shannon E. E. Cooney, Eric Schreiber, William W. W. Brennessel, Ellen M. M. Matson
Summary: Anionic dopants, such as O-atom vacancies, have a significant impact on the thermochemical and kinetic parameters of proton coupled electron transfer (PCET) at metal oxide surfaces. To gain insights, polyoxovanadate-alkoxide clusters are used as models of reducible metal oxide surfaces. The study shows that the presence of O-atom defects weakens the O-H bond strength and enhances the rate of H-atom uptake due to reduced activation barriers for H-atom transfer at the cluster surface.
INORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Physical
Hanae Takeda, Kanji Shimba, Masaki Horitani, Tetsunari Kimura, Takashi Nomura, Minoru Kubo, Yoshitsugu Shiro, Takehiko Tosha
Summary: The characterization of short-lived reaction intermediates is crucial for understanding the mechanism of metalloenzyme-catalyzed reactions. In this study, we demonstrated that the photolysis of a caged compound followed by thermal annealing is an effective technique for trapping short-lived reaction intermediates of metalloenzymes. By applying this technique to the study of membrane-integrated nitric oxide reductase (NOR), we were able to trap and characterize the intermediate species involved in the reductive coupling of NO molecules by NOR at its heme/nonheme FeB binuclear center.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Article
Chemistry, Multidisciplinary
Nicole M. B. Cogan, Kevin P. Mcclelland, Chari Y. M. Peter, Chayan Carmenate Rodriguez, Alex A. Fertig, Mitesh Amin, William W. Brennessel, Todd D. Krauss, Ellen M. Matson
Summary: A limitation in the implementation of cadmium chalcogenide quantum dots (QDs) in charge transfer systems is the efficient removal of photogenerated holes. This study shows that incorporating oxygen vacancies into polyoxovanadate-alkoxide clusters can improve hole transfer kinetics and facilitate QD-hole acceptor association through reversible complexation.
Article
Chemistry, Inorganic & Nuclear
Mamta Dagar, D. M. M. Mevan Dissanyake, Daniel N. Kesler, Molly Corr, Joshua D. Mcpherson, William W. Brennessel, James R. Mckone, Ellen M. Matson
Summary: This study demonstrates that the solubility of organic functionalized titanium-substituted polyoxovanadate-alkoxide clusters could be significantly increased in acetonitrile, leading to potential applications in non-aqueous redox flow batteries. The experimental results provide new insights into the impact of structural modifications on the physicochemical properties of these assemblies.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Multidisciplinary
Medina Afandiyeva, Xijue Wu, William W. Brennessel, Abhishek A. Kadam, C. Rose Kennedy
Summary: This paper describes a novel nickel catalyst and its effective application in the hydroboration of nitriles. By using a tethered NHC-pyridonate ligand, both reagents can be activated simultaneously, enabling efficient catalysis at room temperature.
CHEMICAL COMMUNICATIONS
(2023)
