Article
Chemistry, Inorganic & Nuclear
Sriram Sundaresan, Marcel Diehl, Luca M. Carrella, Eva Rentschler
Summary: This study reports the synthesis of a new octadentate ligand and its combination with a known compound to prepare di-nuclear cobalt complexes. The obtained complexes were characterized and their structure and magnetic properties were studied. The results indicate the occurrence of valence tautomerism in some of the complexes.
Article
Chemistry, Multidisciplinary
K. C. Khadanand, Toby Woods, Lisa Olshansky
Summary: In mononuclear monodioxolene cobalt complexes, the transition from low spin to high spin state has been achieved by modifying the ligand structure, and the magnetic switching in the intermediate state has been observed for the first time, which may provide a new criterion for the design of stimulus-responsive multi-state molecular switches.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Minoru Mitsumi, Yuuki Komatsu, Masahiro Hashimoto, Koshiro Toriumi, Yasutaka Kitagawa, Yuji Miyazaki, Hiroki Akutsu, Haruo Akashi
Summary: This study reports a one-dimensional rhodium-dioxolene complex that exhibits drastic changes in properties during phase transition. The room-temperature phase is in a mixed-valence state, leading to the appearance of the mixed-valence state and increased displacements of rhodium atoms along the 1D chain. These results suggest a possible mechanism for the appearance of mixed-valence state based on thermal electron transfer and large-amplitude vibration of the Rh-Rh bonds.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Physics, Condensed Matter
A. A. Guda, M. Chegerev, A. G. Starikov, V. G. Vlasenko, A. A. Zolotukhin, M. P. Bubnov, V. K. Cherkasov, V. V. Shapovalov, Yu Rusalev, A. A. Tereshchenko, A. L. Trigub, A. Chernyshev, A. Soldatov
Summary: Valence tautomer transition primarily occurs in 3d metalorganic complexes with redox-active ligands, making them potential candidates for single-molecular switches. In this study, bis(o-semiquinonato) cobalt complex with TEMPO-functionalized iminopyridine ancillary ligand was investigated using ligand-sensitive FTIR and metal-sensitive Co K-edge XAS techniques. The results showed a temperature hysteresis of magnetization larger than 40 K in the solid state, with XAS being advantageous for liquid phase analysis and FTIR having larger sensitivity to ligand related interactions in solid.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Article
Chemistry, Inorganic & Nuclear
Xiao-Peng Sun, Zheng Tang, Jiajia Li, Pengtao Ma, Zi-Shuo Yao, Jingping Wang, Jingyang Niu, Jun Tao
Summary: This study fully investigated two isostructural valence tautomeric complexes with different critical temperatures using a series of magnetic, structural, spectral, and differential scanning calorimetry evidence. The kinetic effect in the valence tautomeric complex was observed for the first time through scan-rate-dependent studies and further validated by annealing tests.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Christoph Metzger, Ramapada Dolai, Sabine Reh, Harald Kelm, Markus Schmitz, Benjamin Oelkers, Mathias Sawall, Klaus Neymeyr, Hans-Joerg Krueger
Summary: The synthesis and characterization of a monocationic cobalt(III) catecholate complex [Co(L-(N4Bu2)-Bu-t)(Cl(2)cat)](+) (L-(N4Bu2)-Bu-t=N,N'-Di-tert.-butyl-2,11-diaza[3.3](2,6)pyridinophane, Cl(2)cat(2-)=4,5-dichlorocatecholate) are reported. The complex displays valence tautomeric properties, with a unique conversion from a cobalt(III) catecholate to a low-spin cobalt(II) semiquinonate state upon increasing temperature. This new type of valence tautomerism in a cobalt dioxolene complex has been confirmed through detailed spectroscopic investigations.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Biochemistry & Molecular Biology
Abbas Salimi, Sompriya Chatterjee, Jin Yong Lee
Summary: Controlling protein misfolding in neurodegenerative diseases with electric fields (EFs) has potential therapeutic applications. The effect of EFs on the conformational dynamics of beta-Amyloid40 (Aβ40) under histidine tautomerism was studied. Peptides aligned with the EF direction and the dipole moment magnitude depended on EF strength. An EF strength of 0.5 V/nm disrupted the beta-sheet content of the potentially toxic delta delta delta isomer and reduced the alpha-helical structure. The strength of the EF also influenced the number of intra-protein hydrogen bonds, destabilizing the peptides. These findings provide insights into using EFs as a therapeutic technique for neurodegeneration.
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
(2023)
Article
Chemistry, Multidisciplinary
Aditi Singh, Sanjib Panda, Sanchaita Dey, Goutam Kumar Lahiri
Summary: The study emphasized the impact of metal-to-ligand charge transfer on the redox properties of 2,2'-azobis(benzothiazole) and identified a series of mononuclear and dinuclear complexes with different oxidation states. Through spectroelectrochemistry and DFT analysis, the electron reservoir feature of the complexes in various redox states was revealed, demonstrating their stable electron storage capability.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Biochemistry & Molecular Biology
Ilya G. Shenderovich, Gleb S. Denisov
Summary: The study demonstrates the importance of using the polarizable continuum approximation in solvent effect calculations to distinguish between the macroscopic reaction field of the solvent and specific solute-solvent interactions. Additionally, experimental data highlights the significance of the solvent effect in nonpolar solvents.
Review
Chemistry, Multidisciplinary
Baoying Dai, Jiahao Guo, Chenchen Gao, Hang Yin, Yannan Xie, Zhiqun Lin
Summary: Significant progress has been made in enhancing photocatalytic performance through modulation of electric and magnetic fields. The research directions of electric field modulation, magnetic field manipulation, and reactive phase control have received increasing attention. This review examines recent advances in each of these areas, discusses specific examples and mechanisms, and presents challenges and potential opportunities for further improving photocatalytic efficiency.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Christopher J. H. Smalley, Andrew J. Logsdail, Colan E. Hughes, Dinu Iuga, Mark T. Young, Kenneth D. M. Harris
Summary: We report the solid-state structural properties and tautomeric interconversion of alloxazine, a tricyclic ring system found in biologically important molecules. The crystal structures containing both alloxazine and isoalloxazine tautomers were characterized by powder X-ray diffraction (XRD) and high-resolution solid-state N-15 NMR. Computational calculations were also performed to determine the relative energies and mechanisms of tautomeric interconversion. The results show that the alloxazine tautomer is favored in the crystal structure, with over 99.9% of the molecules existing in this form at ambient temperature.
CRYSTAL GROWTH & DESIGN
(2022)
Article
Chemistry, Inorganic & Nuclear
Andrey G. Starikov, Alyona A. Starikova, Maxim G. Chegerev, Sergey M. Aldoshin, Anatoly Metelitsa, Vladimir Minkin
Summary: Density functional theory calculations were used to study the electronic structure, energy characteristics, and magnetic properties of a series of heterometallic CrCo complexes. The compounds prone to spin-state switching involving cobalt center were identified, opening prospects for the purposeful search of new magnetically bistable heterometallic dinuclear paramagnetic species with potential applications in smart dynamic materials design.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2021)
Review
Multidisciplinary Sciences
Ramamoorthy Ramesh, Sasikanth Manipatruni
Summary: The article discusses the exciting research area of electric field control of magnetism, highlighting the potential in both fundamental science and applications, and the need for further innovations and translation into real-world applications.
PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2021)
Article
Chemistry, Physical
Venelin Enchev, Nadezhda Markova
Summary: 2-Carbamido-1,3-indandione (CAID) is a reliable fluorescent biomarker with two tautomeric forms A and B, which are influenced by the strength and direction of an applied electric field.
INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Bin Peng, Qi Lu, Haowen Tang, Yao Zhang, Yuxin Cheng, Ruibin Qiu, Yunting Guo, Ziyao Zhou, Ming Liu
Summary: In this study, researchers achieved a larger voltage control of magnetic anisotropy (VCMA) effect in thin films compared to bulk counterparts. This was made possible by utilizing the large in-plane piezo-strain mediated magnetoelectric coupling under strong fields. This finding is significant for developing integrated magnetic and spintronic devices.
MATERIALS HORIZONS
(2022)
Article
Chemistry, Physical
Heesoo Park, Syam R. Kumar, Akinlolu Akande, Stefano Sanvito, Fedwa El-Mellouhi
Summary: Niobates, tantalates, and bismuthates have shown potential as substitutes for lead-halide perovskites in photonics and energy-harvesting applications. In this study, first-principles materials design was used to investigate the electrochemical potential of certain Nb-, Ta-, and Bi-based oxides/chalcogenides. The analysis revealed that some compounds exhibited reduced electronic dimensionality despite their higher structural dimensionality. The computational results indicated that certain Bi-based chalcogenides, namely KBiO2 and KBiS2, showed efficient photocatalytic performance under various pH conditions.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Nanoscience & Nanotechnology
Lei Zhang, Cheng Tang, Stefano Sanvito, Yuantong Gu, Aijun Du
Summary: Researchers have successfully achieved strong magnetoelectric coupling in a hydrogen-intercalated 2D MnPSe3 bilayer, observing ferroelectricity-controlled magnetic phase transition and half-metallicity. This discovery opens up a new avenue for realizing strong magnetoelectric coupling in single-phase multiferroic materials.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
David Maximilian Janas, Andrea Droghetti, Stefano Ponzoni, Iulia Cojocariu, Matteo Jugovac, Vitaliy Feyer, Milos M. Radonjic, Ivan Rungger, Liviu Chioncel, Giovanni Zamborlini, Mirko Cinchetti
Summary: This study combines spin-resolved momentum microscopy and theoretical calculations beyond the one-electron approximation to investigate the spin-dependent electronic structure of the interface between iron and an ordered oxygen atomic layer. An enhancement of electronic correlations induced by adsorption is discovered, leading to a narrowing of the Fe d-bands near the Fermi energy and a reduction of the exchange splitting. Moreover, correlation effects result in a significant spin-dependent broadening of the electronic bands at higher binding energies and their merging with satellite features, indicating many-electron behavior.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Cheng Tang, Lei Zhang, Stefano Sanvito, Aijun Du
Summary: A general strategy for achieving 2D triferroicity by imposing electric polarization into a ferroelastic magnet is proposed in this study, and dual transition-metal dichalcogenides, such as 1T'-CrCoS4, are demonstrated to display room temperature triferroicity. The 1T'-CrCoS4 monolayer shows negative out-of-plane piezoelectricity and strain-tunable magnetic anisotropy, making it a strong candidate for practical applications. This research introduces a new class of 2D room-temperature triferroic materials, providing a promising platform for advanced spintronics.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Yuxuan Jiang, Shi Li, Yudi Wang, Haoyang Pan, Yongfeng Wang, Stefano Sanvito, Shimin Hou
Summary: The retention of open-shell character of organic radicals in contact with metal electrodes is crucial for their applications in molecular electronic devices. By using first-principles quantum transport calculations, the stability and electronic transport properties of single-molecule junctions incorporating a Blatter radical (BR) have been investigated. The calculations show that the BR can retain its open-shell nature even when bound to gold electrodes through undercoordinated gold adatoms, and the conductance values of junctions with BR are in agreement with experimental measurements. This study deepens the understanding of radical-metal interfacial properties and aids in the design of radical-based molecular devices.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Bruno Focassio, Michelangelo Domina, Urvesh Patil, Adalberto Fazzio, Stefano Sanvito
Summary: Kohn-Sham density functional theory (KS-DFT) is a powerful method used to obtain important material properties, but the computational costs associated with solving the KS equations limit its application to complex systems. To overcome this, machine learning (ML) models can be employed as surrogates to accurately predict the converged DFT charge density, allowing for faster and more cost-effective computations.
NPJ COMPUTATIONAL MATERIALS
(2023)
Article
Computer Science, Artificial Intelligence
Laura Gambini, Tiarnan Mullarkey, Lewys Jones, Stefano Sanvito
Summary: High-resolution electron microscopy requires a high electron dose, which can damage the specimen and affect observation. Our work utilizes machine learning to improve the quality of Scanning Transmission Electron Microscope images generated at low electron dose, effectively reducing noise levels and approaching ground-truth precision.
MACHINE LEARNING-SCIENCE AND TECHNOLOGY
(2023)
Article
Physics, Applied
Joshua F. Belot, Valentin Taufour, Stefano Sanvito, Gus L. W. Hart
Summary: Researchers developed machine-learning models based on the chemical composition of materials to predict Curie temperatures. A random-forest model provided the most accurate predictions and did not require dimensionality reduction or complex descriptors. Cobalt-rich and iron-rich materials showed the highest Curie temperatures among binary and ternary compounds.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Physical
Rui Dong, Alessandro Lunghi, Stefano Sanvito
Summary: This study uses chemically accurate ab initio machine learning force fields in molecular dynamics simulations to investigate the effect of layer stiffness on the superlubricant state of two-dimensional van der Waals heterostructures. It is found that increasing the intralayer stiffness leads to a significant reduction in friction. Two sliding regimes, characterized by different heat exchange and temperature profiles, are observed at different sliding velocities.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Yudi Wang, Haoyang Pan, Dongying Lin, Shi Li, Yongfeng Wang, Stefano Sanvito, Shimin Hou
Summary: In molecular electronics, electrode-molecule anchoring strategies are crucial in the design of stable and high-performance functional single-molecule devices. In this study, we used aromatic pyrazine as anchors to connect a central anthracene molecule to carbon electrodes, and investigated their atomic structures and electronic transport properties theoretically. The pyrazine anchors facilitated the formation of stable and well-defined molecular junctions, and could also modulate the polarity of charge carriers in carbon-electrode molecular electronic devices.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Jacopo Simoni, Stefano Sanvito
Summary: The total angular momentum of a closed system should remain constant in time, but it is not satisfied in real-time simulations. The simplified description of spin-orbit coupling neglects the contribution of itinerant electrons. The conservation can be reintroduced through proper choice of spin-orbit coupling.
Article
Materials Science, Multidisciplinary
Matteo Cobelli, Paddy Cahalane, Stefano Sanvito
Summary: In this paper, an optimization method is presented to invert the local many-body descriptors of the chemical environment back to a Cartesian representation. This enables finding the Cartesian representation of known structure variations. The algorithm, implemented with the bispectrum representation, is demonstrated for molecules with different bonding structures and atomic species, making it a convenient approach for constructing structural generative models.
Article
Materials Science, Multidisciplinary
James Nelson, Luuk Coopmans, Graham Kells, Stefano Sanvito
Summary: We investigate the potential of supervised machine learning to propagate a quantum system in time. We find that for non-Markovian systems, their description requires the memory knowledge of past states, and the number of past states required grows exponentially with the number of spins and with the density of the system spectrum. Additionally, we demonstrate that neural networks can work as time propagators and can be concatenated in time to form an autoregression.
Article
Materials Science, Multidisciplinary
M. Domina, M. Cobelli, S. Sanvito
Summary: This paper introduces a method for representing vector fields with translational and rotational invariance, which can be utilized in the construction of machine learning energy models for solids and molecules. The method allows for the description of energy fluctuations due to atomic motion, longitudinal and transverse excitations of the vector field, and their interactions. The method can be applied to physical systems where the total energy is determined by a vector density.
Article
Materials Science, Multidisciplinary
Gokaran Shukla, Stefano Sanvito, Geunsik Lee
Summary: This study explores the potential of AlN and ZnO as insulating barrier materials in magnetic tunnel junctions. The experimental results show that AlN and ZnO have band structures suitable for spin filtering, which may result in a large tunneling magnetoresistance.
