200 results on '"Enrique R. Batista"'
Search Results
2. Architector for high-throughput cross-periodic table 3D complex building
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Michael G. Taylor, Daniel J. Burrill, Jan Janssen, Enrique R. Batista, Danny Perez, and Ping Yang
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Science - Abstract
Abstract Rare-earth and actinide complexes are critical for a wealth of clean-energy applications. Three-dimensional (3D) structural generation and prediction for these organometallic systems remains a challenge, limiting opportunities for computational chemical discovery. Here, we introduce Architector, a high-throughput in-silico synthesis code for s-, p-, d-, and f-block mononuclear organometallic complexes capable of capturing nearly the full diversity of the known experimental chemical space. Beyond known chemical space, Architector performs in-silico design of new complexes including any chemically accessible metal-ligand combinations. Architector leverages metal-center symmetry, interatomic force fields, and tight binding methods to build many possible 3D conformers from minimal 2D inputs including metal oxidation and spin state. Over a set of more than 6,000 x-ray diffraction (XRD)-determined complexes spanning the periodic table, we demonstrate quantitative agreement between Architector-predicted and experimentally observed structures. Further, we demonstrate out-of-the box conformer generation and energetic rankings of non-minimum energy conformers produced from Architector, which are critical for exploring potential energy surfaces and training force fields. Overall, Architector represents a transformative step towards cross-periodic table computational design of metal complex chemistry.
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- 2023
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3. Author Correction: Architector for high-throughput cross-periodic table 3D complex building
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Michael G. Taylor, Daniel J. Burrill, Jan Janssen, Enrique R. Batista, Danny Perez, and Ping Yang
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Science - Published
- 2023
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4. N2-to-NH3 conversion by excess electrons trapped in point vacancies on 5f-element dioxide surfaces
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Gaoxue Wang, Enrique R. Batista, and Ping Yang
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N2-to-NH3 conversion ,excess electrons ,point vacancies ,actinide dioxide surfaces ,DFT density functional theory ,Chemistry ,QD1-999 - Abstract
Ammonia (NH3) is one of the basic chemicals in artificial fertilizers and a promising carbon-free energy storage carrier. Its industrial synthesis is typically realized via the Haber−Bosch process using traditional iron-based catalysts. Developing advanced catalysts that can reduce the N2 activation barrier and make NH3 synthesis more efficient is a long-term goal in the field. Most heterogeneous catalysts for N2-to-NH3 conversion are multicomponent systems with singly dispersed metal clusters on supporting materials to activate N2 and H2 molecules. Herein, we report single-component heterogeneous catalysts based on 5f actinide dioxide surfaces (ThO2 and UO2) with oxygen vacancies for N2-to-NH3 conversion. The reaction cycle we propose is enabled by a dual-site mechanism, where N2 and H2 can be activated at different vacancy sites on the same surface; NH3 is subsequently formed by H− migration on the surface via associative pathways. Oxygen vacancies recover to their initial states after the release of two molecules of NH3, making it possible for the catalytic cycle to continue. Our work demonstrates the catalytic activities of oxygen vacancies on 5f actinide dioxide surfaces for N2 activation, which may inspire the search for highly efficient, single-component catalysts that are easy to synthesize and control for NH3 conversion.
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- 2023
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5. δ and φ back-donation in AnIV metallacycles
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Morgan P. Kelley, Ivan A. Popov, Julie Jung, Enrique R. Batista, and Ping Yang
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Science - Abstract
Metal-ligand δ and φ interactions, though considered weak, may be necessary for fully describing the electronic and geometric structures of certain compounds. Here, in actinide metallacycles, the authors discover two new types of M-L δ and φ back-bonds that contribute substantially to their unusual chemical behavior.
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- 2020
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6. Impact of Ligand Substitutions on Multielectron Redox Properties of Fe Complexes Supported by Nitrogenous Chelates
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Ivan A. Popov, Nada Mehio, Terry Chu, Benjamin L. Davis, Rangachary Mukundan, Ping Yang, and Enrique R. Batista
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Chemistry ,QD1-999 - Published
- 2018
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7. Synthesis and Characterization of the Actinium Aquo Ion
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Maryline G. Ferrier, Benjamin W. Stein, Enrique R. Batista, John M. Berg, Eva R. Birnbaum, Jonathan W. Engle, Kevin D. John, Stosh A. Kozimor, Juan S. Lezama Pacheco, and Lindsay N. Redman
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Chemistry ,QD1-999 - Published
- 2017
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8. Catalyst-Inspired Charge Carriers for High Energy Density Redox Flow Batteries
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Ivan A. Popov, Benjamin L. Davis, Rangachary Mukundan, Enrique R. Batista, and Ping Yang
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redox flow batteries (RFB) ,catalyst-inspired ,computational modeling ,density functional theory ,Fe-complex ,redox potentials ,Physics ,QC1-999 - Abstract
We introduce a theoretical design approach aiming at improving energy density of redox flow batteries (RFBs) via the utilization of redox non-innocent ligands capable of stabilizing a metal center in a wide range of oxidation states. Our findings suggest that this promotes the possibility of multiple redox events as well as high open circuit voltages. Specifically, we have proposed two Fe-coordination complexes (I, Fe(Me2Pytacn)(C2N3H2), and II, Fe(H2pmen)(C2N3H2)) combining two different types of ligands, i.e., catalyst-inspired scaffolds and triazole ring, which were previously shown to promote high and low oxidation states in transition metals, respectively. These complexes exhibit as many as six theoretical redox events in the full range of charge states +4 → −2, several of which reside within the electrochemical window of acetonitrile. Electronic structure calculations show that the Fe center exhibits oxidation states ranging from the very rare Fe4+ to Fe1+. Values of the reduction potentials as well as nature of the redox events of both complexes is found to be similar in their high +4 → +1 charge states. In contrast, while exhibiting qualitatively similar redox behavior in the lower 0 → −2 range, some differences in the electronic ground states, delocalization patterns as well as reduction potential values are also observed. The calculated open circuit voltages can reach values of 5.09 and 6.14 V for complexes I and II, respectively, and hold promise to be experimentally accessible within the electrochemical window of acetonitrile expanded by addition of ionic liquids. The current results obtained for these two complexes are intended to illustrate a more general principle based on the simultaneous utilization of two types of ligands responsible for the stabilization of high and low oxidation states of the metal that can be used to design the next-generation charge carriers capable of supporting multi-electron redox and operating in a broad range of charge states, leading to RFBs with greater energy density.
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- 2019
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9. Spectroscopic and computational investigation of actinium coordination chemistry
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Maryline G. Ferrier, Enrique R. Batista, John M. Berg, Eva R. Birnbaum, Justin N. Cross, Jonathan W. Engle, Henry S. La Pierre, Stosh A. Kozimor, Juan S. Lezama Pacheco, Benjamin W. Stein, S. Chantal E. Stieber, and Justin J. Wilson
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Science - Abstract
Actinium-225 is a promising isotope for α-therapy but progress in developing its chemistry is hindered by its high radioactivity and short supply. Here, the authors characterize actinium coordination in HCl solutions using X-ray absorption spectroscopy and molecular dynamics density functional theory.
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- 2016
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10. Water on Actinide Dioxide Surfaces: A Review of Recent Progress
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Gaoxue Wang, Enrique R. Batista, and Ping Yang
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actinide dioxide ,surface chemistry ,water splitting ,density functional theory ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
The fluorite structured actinide dioxides (AnO2), especially UO2, are the most common nuclear fuel materials. A comprehensive understanding of their surface chemistry is critical because of its relevance to the safe handling, usage, and storage of nuclear fuels. Because of the ubiquitous nature of water (H2O), its interaction with AnO2 has attracted significant attention for its significance in studies of nuclear fuels corrosion and the long-term storage of nuclear wastes. The last few years have seen extensive experimental and theoretical studies on the H2O–AnO2 interaction. Herein, we present a brief review of recent advances in this area. We focus on the atomic structures of AnO2 surfaces, the surface energies, surface oxygen vacancies, their influence on the oxidation states of actinide atoms, and the adsorption and reactions of H2O on stoichiometric and reduced AnO2 surfaces. Finally, a summary and outlook of future studies on surface chemistry of AnO2 are given. We intend for this review to encourage broader interests and further studies on AnO2 surfaces.
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- 2020
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11. Kinetics of alkali-based photocathode degradation
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Vitaly Pavlenko, Fangze Liu, Mark A. Hoffbauer, Nathan A. Moody, and Enrique R. Batista
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Physics ,QC1-999 - Abstract
We report on a kinetic model that describes the degradation of the quantum efficiency (QE) of Cs3Sb and negative electron affinity (NEA) GaAs photocathodes under UHV conditions. In addition to the generally accepted irreversible chemical change of a photocathode’s surface due to reactions with residual gases, such as O2, CO2, and H2O, the model incorporates an intermediate reversible physisorption step, similar to Langmuir adsorption. This intermediate step is needed to satisfactorily describe the strongly non-exponential QE degradation curves for two distinctly different classes of photocathodes –surface-activated and “bulk,” indicating that in both systems the QE degradation results from surface damage. The recovery of the QE upon improvement of vacuum conditions is also accurately predicted by this model with three parameters (rates of gas adsorption, desorption, and irreversible chemical reaction with the surface) comprising metrics to better characterize the lifetime of the cathodes, instead of time-pressure exposure expressed in Langmuir units.
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- 2016
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12. Pairwise Difference Regression: A Machine Learning Meta-algorithm for Improved Prediction and Uncertainty Quantification in Chemical Search.
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Michael Tynes, Wenhao Gao 0001, Daniel J. Burrill, Enrique R. Batista, Danny Perez, Ping Yang, and Nicholas Lubbers
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- 2021
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13. Uranium-Mediated Peroxide Activation and a Precursor toward an Elusive Uranium cis-Dioxo Fleeting Intermediate
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Douglas R. Hartline, Sascha T. Löffler, Dominik Fehn, Joseph M. Kasper, Frank W. Heinemann, Ping Yang, Enrique R. Batista, and Karsten Meyer
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Colloid and Surface Chemistry ,General Chemistry ,Biochemistry ,Catalysis - Published
- 2023
14. Influencing Bonding Interactions of the Neptunyl (V, VI) Cations with Electron-Donating and -Withdrawing Groups
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Logan J. Augustine, Joseph M. Kasper, Tori Z. Forbes, Sara E. Mason, Enrique R. Batista, and Ping Yang
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Inorganic Chemistry ,Physical and Theoretical Chemistry - Published
- 2023
15. State Interaction Linear Response Time-Dependent Density Functional Theory with Perturbative Spin–Orbit Coupling: Benchmark and Perspectives
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Can Liao, Joseph M. Kasper, Andrew J. Jenkins, Ping Yang, Enrique R. Batista, Michael J. Frisch, and Xiaosong Li
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- 2023
16. Relativistic Effects in Modeling the Ligand K-Edge X-ray Absorption Near-Edge Structure of Uranium Complexes
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Joseph M. Kasper, Xiaosong Li, Stosh A. Kozimor, Enrique R. Batista, and Ping Yang
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Physical and Theoretical Chemistry ,Computer Science Applications - Abstract
Accurate modeling of the complex electronic structure of actinide complexes requires full inclusion of relativistic effects. In this study, we examine the effect of explicit inclusion of spin-orbit coupling (SOC) versus scalar relativistic effects on the predicted spectra for heavy-element complexes. In this study, we employ a relativistic two-component Hamiltonian in the X2C form with all of the electrons in the system being considered explicitly to compare and contrast with previous studies that included the relativistic effects by means of relativistic effective core potentials (RECPs). A few uranium complexes are chosen as model systems. Comparison of the computed Cl K-edge X-ray absorption spectra with experimental data shows significantly improved agreement when a variational relativistic treatment of SOC is performed. In particular, we note the importance of SOC terms to obtain not only correct transition energies but also correct intensities for these heavy-element complexes because of the redistribution of ligand bonding character among the valence MOs. While RECPs generally agree well with all-electron scalar relativistic calculations, there are some differences in the predicted spectra of open-shell systems. These methods are still suitable for broad application to analyze the qualitative nature of transitions in X-ray absorption spectra, but caution is recommended for quantitative analysis, as SOC can be non-negligible for both open- and closed-shell heavy-element systems.
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- 2022
17. Spectroscopic and electrochemical characterization of a Pr4+ imidophosphorane complex and the redox chemistry of Nd3+ and Dy3+ complexes
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Natalie T. Rice, Ivan A. Popov, Rebecca K. Carlson, Samuel M. Greer, Andrew C. Boggiano, Benjamin W. Stein, John Bacsa, Enrique R. Batista, Ping Yang, and Henry S. La Pierre
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Inorganic Chemistry - Abstract
Tetravalent praseodymium in a homoleptic imidophosphorane complex is identified and characterized in solution via UV-vis-NIR, cyclic voltammetry, theoretical calculations, and X-band EPR.
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- 2022
18. Hyperspectral X-Ray Imaging: Progress Towards Chemical Analysis in the SEM
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Ping Yang, Katrina Koehler, Eric G. Bowes, Enrique R. Batista, Gene C. Hilton, M. H. Carpenter, Carl D. Reintsema, Douglas A. Bennett, Daikang Yan, Johnathon D. Gard, Zachary K. Baker, Daniel S. Swetz, Michael W. Rabin, M. P. Croce, Katherine A. Schreiber, Gregory L. Wagner, Joel C. Weber, Daniel T. Becker, Daniel Schmidt, Benjamin W. Stein, Chandler M. Smith, Christopher J. Fontes, Galen C. O'Neil, Abigail L. Wessels, Joel N. Ullom, Matthew L. Handley, J. Imrek, Kelsey M. Morgan, John A. B. Mates, and Daniel G. McNeel
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Cryostat ,Materials science ,Pixel ,Scanning electron microscope ,business.industry ,Detector ,Hyperspectral imaging ,Condensed Matter Physics ,01 natural sciences ,Sample (graphics) ,Electronic, Optical and Magnetic Materials ,Chemical species ,Optics ,0103 physical sciences ,Electrical and Electronic Engineering ,010306 general physics ,business ,Microwave - Abstract
The Hyperspectral X-ray Imaging (HXI) project will enable non-destructive chemical-state determination of nano-scale samples in the electron microscope for nuclear safeguards applications. To efficiently measure chemical state through electron-excited X-ray emission requires a combination of wide spectral bandwidth, high resolution, and high count rate capability. We are building a next-generation X-ray detector based on an array of transition edge sensors (TESs) to make these measurements possible and routine in the scanning electron microscope (SEM). Leveraging the large pixel densities afforded by microwave multiplexing readout and continuous, uninterrupted operation of a cryogen-free dilution refrigerator, this instrument will have efficiency to allow chemical species identification of nano-scale samples in hours instead of days to weeks. We describe prototype pixel designs for this HXI instrument, comprising three pixel types that will make up the hybrid TES array. Engineering design of the integrated HXI cryostat and SEM system is in progress, with full detector commissioning expected in Spring 2021 followed closely by full-scale integration with the SEM. We also report on the commissioning of a complementary TES-based X-ray emission spectroscopy platform for bulk samples to build a spectral library for HXI sample identification.
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- 2021
19. Hydrazine Energy Storage: Displacing N 2 H 4 from the Metal Coordination Sphere
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Andrew J. McNeece, Adam Jaroš, Enrique R. Batista, Ping Yang, Brian L. Scott, and Benjamin L. Davis
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General Energy ,General Chemical Engineering ,Environmental Chemistry ,General Materials Science - Published
- 2022
20. High Resolution X-Ray Spectra for Chemical Speciation in the SEM
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Eric G. Bowes, Lei Xu, Chandler M. Smith, Michael W. Rabin, Enrique R. Batista, Benjamin W. Stein, M. P. Croce, Katherine A. Schreiber, M. H. Carpenter, Christopher J. Fontes, Katrina Koehler, Daniel G. McNeel, Gregory L. Wagner, and Ping Yang
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Materials science ,Chemical speciation ,Analytical chemistry ,High resolution ,Instrumentation ,X ray spectra - Published
- 2021
21. Iron-iminopyridine complexes as charge carriers for non-aqueous redox flow battery applications
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Ivan A. Popov, Benjamin L. Davis, Aaron M. Tondreau, Ping Yang, Enrique R. Batista, Gabriel A. Andrade, Shikha Sharma, John C. Gordon, Sandip Maurya, Nathan C. Smythe, and Rangachary Mukundan
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Aqueous solution ,Materials science ,Renewable Energy, Sustainability and the Environment ,Energy Engineering and Power Technology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,Combinatorial chemistry ,Flow battery ,Redox ,Energy storage ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,General Materials Science ,0210 nano-technology ,Acetonitrile ,Faraday efficiency ,Diimine - Abstract
Non-aqueous redox flow batteries (RFBs) have been gaining increased attention in the energy storage arena. Some of their attractive features include the promise for high energy densities, wider voltage windows compared to aqueous systems, as well as wider operating temperature ranges. One of the major challenges in the development of these systems is the lack of electroactive materials that can undergo reversible redox events within the larger potential window of organic solvents. Herein, we present the design, synthesis, and measurement of electrochemical properties of some iron-based imine- and iminopyridine complexes as promising candidates for RFB applications. Synthesized complexes afforded three reversible redox couples over a ~3 V range. The redox events were also computationally explored and are in good agreement with experimental data. Theoretical calculations show that the redox event at the positive potential can be characterized as metal-centered event corresponding to Fe3+→ Fe2+ reduction, while the two redox events at negative potentials are associated with the consecutive reductions of iminopyridine or diimine moieties. This work has led to the identification of a promising anolyte material, [tris(imino)pyridine)Fe][OTf]2 (1), which is soluble in acetonitrile and is synthesized in two simple steps. This species shows outstanding performance when cycled between 1.0 V and 2.35 V, with 93% coulombic efficiency, 84% energy efficiency, and a capacity decay rate of 0.61% per cycle at 5 mA cm−2. Further modifications to this kind of charge carrier may lead to the development of high energy density materials for grid scale energy storage applications.
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- 2021
22. Advancing the Am Extractant Design through the Interplay among Planarity, Preorganization, and Substitution Effects
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Xiaobin Zhang, Sara L. Adelman, Brian T. Arko, Channa R. De Silva, Jing Su, Stosh A. Kozimor, Veronika Mocko, Jenifer C. Shafer, Benjamin W. Stein, Georg Schreckenbach, Enrique R. Batista, and Ping Yang
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Inorganic Chemistry ,Ions ,Americium ,Coordination Complexes ,Physical and Theoretical Chemistry - Abstract
Advancing the field of chemical separations is important for nearly every area of science and technology. Some of the most challenging separations are associated with the americium ion Am(III) for its extraction in the nuclear fuel cycle
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- 2022
23. Synthesis, solid-state, solution, and theoretical characterization of an 'in-cage' scandium-NOTA complex
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Kelly E. Aldrich, Ivan A. Popov, Harrison D. Root, Enrique R. Batista, Samuel M. Greer, Stosh A. Kozimor, Laura M. Lilley, Maksim Y. Livshits, Veronika Mocko, Michael T. Janicke, Brian L. Scott, Benjamin W. Stein, and Ping Yang
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Inorganic Chemistry ,Heterocyclic Compounds, 1-Ring ,Ligands ,Scandium ,Chelating Agents - Abstract
Developing chelators that strongly and selectively bind rare-earth elements (Sc, Y, La, and lanthanides) represents a longstanding fundamental challenge in inorganic chemistry. Solving these challenges is becoming more important because of increasing use of rare-earth elements in numerous technologies, ranging from paramagnets to luminescent materials. Within this context, we interrogated the complexation chemistry of the scandium(III) (Sc
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- 2022
24. Two-Dimensional Nanomaterials as Anticorrosion Surface Coatings for Uranium Metal: Physical Insights from First-Principles Theory
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Qing Guo, Kah Chun Lau, Gaoxue Wang, Enrique R. Batista, and Ping Yang
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Materials science ,Metallurgy ,chemistry.chemical_element ,engineering.material ,Uranium ,Durability ,Nanomaterials ,Corrosion ,Metal ,Coating ,chemistry ,visual_art ,visual_art.visual_art_medium ,engineering ,General Materials Science ,Reliability (statistics) - Abstract
Corrosion protection is vital to ensure the reliability and long-term durability of metal components. Coating surfaces with two-dimensional (2D) materials is an attractive approach due to the stren...
- Published
- 2021
25. Structural and Spectroscopic Comparison of Soft‐Se vs. Hard‐O Donor Bonding in Trivalent Americium/Neodymium Molecules
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Conrad A. P. Goodwin, Anthony W. Schlimgen, Thomas E. Albrecht‐Schönzart, Enrique R. Batista, Andrew J. Gaunt, Michael T. Janicke, Stosh A. Kozimor, Brian L. Scott, Lauren M. Stevens, Frankie D. White, and Ping Yang
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010405 organic chemistry ,chemistry.chemical_element ,Americium ,General Medicine ,General Chemistry ,Actinide ,010402 general chemistry ,01 natural sciences ,Neodymium ,Catalysis ,0104 chemical sciences ,Crystallography ,chemistry ,Ab initio quantum chemistry methods ,Covalent bond ,Molecule ,Spectroscopy ,Selectivity - Abstract
Covalency is often considered to be an influential factor in driving An3+ vs. Ln3+ selectivity invoked by soft donor ligands. This is intensely debated, particularly the extent to which An3+ /Ln3+ covalency differences prevail and manifest as the f-block is traversed, and the effects of periodic breaks beyond Pu. Herein, two Am complexes, [Am{N(E=PPh2 )2 }3 ] (1-Am, E=Se; 2-Am, E=O) are compared to isoradial [Nd{N(E=PPh2 )2 }3 ] (1-Nd, 2-Nd) complexes. Covalent contributions are assessed and compared to U/La and Pu/Ce analogues. Through ab initio calculations grounded in UV-vis-NIR spectroscopy and single-crystal X-ray structures, we observe differences in f orbital involvement between Am-Se and Nd-Se bonds, which are not present in O-donor congeners.
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- 2021
26. Using molten salts to probe outer-coordination sphere effects on lanthanide(<scp>iii</scp>)/(<scp>ii</scp>) electron-transfer reactions
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Kristen A. Pace, Stosh A. Kozimor, Veronika Mocko, Ping Yang, Jennifer N. Wacker, Francisca R. Rocha, Cecilia Eiroa-Lledo, Molly M. MacInnes, Karah E. Knope, Nickolas H. Anderson, Enrique R. Batista, Ida M. DiMucci, Zachary R. Jones, Bo Li, Maksim Y. Livshits, and Benjamin W. Stein
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Inorganic Chemistry ,Metal ,Lanthanide ,Coordination sphere ,Absorption spectroscopy ,Oxidation state ,Chemistry ,visual_art ,visual_art.visual_art_medium ,Physical chemistry ,Molten salt ,Redox ,Ion - Abstract
Controlling structure and reactivity by manipulating the outer-coordination sphere around a given reagent represents a longstanding challenge in chemistry. Despite advances toward solving this problem, it remains difficult to experimentally interrogate and characterize outer-coordination sphere impact. This work describes an alternative approach that quantifies outer-coordination sphere effects. It shows how molten salt metal chlorides (MCln; M = K, Na, n = 1; M = Ca, n = 2) provided excellent platforms for experimentally characterizing the influence of the outer-coordination sphere cations (Mn+) on redox reactions accessible to lanthanide ions; Ln3+ + e1− → Ln2+ (Ln = Eu, Yb, Sm; e1− = electron). As a representative example, X-ray absorption spectroscopy and cyclic voltammetry results showed that Eu2+ instantaneously formed when Eu3+ dissolved in molten chloride salts that had strongly polarizing cations (like Ca2+ from CaCl2) via the Eu3+ + Cl1− → Eu2+ + ½Cl2 reaction. Conversely, molten salts with less polarizing outer-sphere M1+ cations (e.g., K1+ in KCl) stabilized Ln3+. For instance, the Eu3+/Eu2+ reduction potential was >0.5 V more positive in CaCl2 than in KCl. In accordance with first-principle molecular dynamics (FPMD) simulations, we postulated that hard Mn+ cations (high polarization power) inductively removed electron density from Lnn+ across Ln–Cl⋯Mn+ networks and stabilized electron-rich and low oxidation state Ln2+ ions. Conversely, less polarizing Mn+ cations (like K1+) left electron density on Lnn+ and stabilized electron-deficient and high-oxidation state Ln3+ ions.
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- 2021
27. Computer-Assisted Design of Macrocyclic Chelators for Actinium-225 Radiotherapeutics
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Enrique R. Batista, Amanda Morgenstern, Benjamin W. Stein, Laura M. Lilley, Ping Yang, and Stosh A. Kozimor
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Actinium ,Macrocyclic Compounds ,Static Electricity ,Ionic bonding ,chemistry.chemical_element ,Context (language use) ,010402 general chemistry ,01 natural sciences ,Inorganic Chemistry ,chemistry.chemical_compound ,Coordination Complexes ,Static electricity ,Molecule ,Chelation ,Physical and Theoretical Chemistry ,Density Functional Theory ,Chelating Agents ,Molecular Structure ,010405 organic chemistry ,Combinatorial chemistry ,0104 chemical sciences ,chemistry ,Functional group ,Computer-Aided Design ,Density functional theory ,Radiopharmaceuticals - Abstract
Actinium-225 (225Ac) is an excellent candidate for targeted radiotherapeutic applications for treating cancer, because of its 10-day half-life and emission of four high-energy α2+ particles. To harness and direct the energetic potential of actinium, strongly binding chelators that remain stable in vivo during biological targeting must be developed. Unfortunately, controlling chelation for actinium remains challenging. Actinium is the largest +3 cation on the periodic table and has a 6d05f0 electronic configuration, and its chemistry is relatively unexplored. Herein, we present theoretical work focused on improving the understanding of actinium bonding with macrocyclic chelating agents as a function of (1) macrocycle ring size, (2) the number and identity of metal binding functional groups, and (3) the length of the tether linking the metal binding functional group to the macrocyclic backbone. Actinium binding by these chelators is presented within the context of complexation with DOTA4-, the most relevant Ac3+ binding agent for contemporary radiopharmaceutical applications. The results enabled us to develop a new strategy for actinium chelator design. The approach is rooted in our identification that Ac3+-chelation chemistry is dominated by ionic bonding interactions and relies on (1) maximizing electrostatic interactions between the metal binding functional group and the Ac3+ cation and (2) minimizing electronic repulsion between negatively charged actinium binding functional groups. This insight will provide a foundation for future innovation in developing the next generation of multifunctional actinium chelators.
- Published
- 2020
28. Mechanistic Study of the Production of NOx Gases from the Reaction of Copper with Nitric Acid
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Enrique R. Batista, Samuel M. Clegg, Rebecca K. Carlson, and Ping Yang
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chemistry.chemical_element ,Copper ,Inorganic Chemistry ,Metal ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Nitric acid ,Mechanism (philosophy) ,visual_art ,Scientific method ,visual_art.visual_art_medium ,Density functional theory ,Physical and Theoretical Chemistry ,Dissolution ,NOx - Abstract
Copper dissolution in nitric acid is a historic reaction playing a central role in many industrial processes, particularly for metal recovery from the electronics to nuclear industries. The mechanism through which this process occurs is debated. In order to better understand this process, quantum chemical calculations were performed to elucidate the key steps in the mechanism of copper dissolution in nitric acid. We combine both Kohn-Sham density functional theory and ab initio molecular dynamics simulations to understand the mechanism of the formation of the key products: NO2, HNO2, and NO. Our calculations suggest that the mechanisms of formation of NO2, HNO2, and NO are interconnected.
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- 2020
29. Structural and Optical Properties of Phase-Pure UO2, α-U3O8, and α-UO3 Epitaxial Thin Films Grown by Pulsed Laser Deposition
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Quanxi Jia, Joshua T. White, J.T. Dunwoody, Xiaofeng Guo, Erik Enriquez, Hongwu Xu, Andrew T. Nelson, Ping Yang, Yogesh Sharma, Nicholas Winner, Aiping Chen, Ibrahim Sarpkaya, Qiang Wang, Paul Dowden, Enrique R. Batista, Han Htoon, Gaoxue Wang, and Di Chen
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Materials science ,010405 organic chemistry ,business.industry ,Epitaxial thin film ,chemistry.chemical_element ,Uranium ,010402 general chemistry ,Epitaxy ,01 natural sciences ,0104 chemical sciences ,Pulsed laser deposition ,chemistry ,Phase (matter) ,Optoelectronics ,General Materials Science ,Thin film ,business - Abstract
Fundamental understanding of the electronic, chemical, and structural properties of uranium oxides requires the synthesis of high-crystalline-quality epitaxial films of different polymorphs of one ...
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- 2020
30. Tight-Binding Modeling of Uranium in an Aqueous Environment
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Enrique R. Batista, Rebecca K. Carlson, Ping Yang, and Marc J. Cawkwell
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Reaction mechanism ,Materials science ,010304 chemical physics ,Hydrogen ,Kinetics ,chemistry.chemical_element ,Thermodynamics ,Uranium ,01 natural sciences ,Computer Science Applications ,Tight binding ,chemistry ,0103 physical sciences ,Molecule ,Density functional theory ,Physical and Theoretical Chemistry ,Isomerization - Abstract
The first density functional tight-binding (DFTB) parameters for uranium, oxygen, and hydrogen chemistry are reported, which enable quantum molecular dynamics simulations that will be instrumental in understanding actinide speciation, reaction mechanisms, and kinetics. These parameters were fitted to atomization energies and forces obtained from density functional theory with a training set of small molecules that includes various oxidation states. The energetic results with these DFTB parameters for various reactions of hydration, hydrolysis, dimerization, and isomerization demonstrate that the DFTB method can qualitatively capture the correct chemistry with a small systematic deviation from the density functional theory reference values. Structural results on the molecules not in the training set, including dimers, show generally good agreement with the reference and demonstrate the transferability of these first DFTB parameters for uranium chemistry.
- Published
- 2020
31. Hyperspectral X-ray Imaging with TES Detectors for Nanoscale Chemical Speciation Mapping
- Author
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J. A. Hall, D. T. Carver, Chris J. Fontes, J. D. Gard, Galen C. O'Neil, Ping Yang, D. T. Becker, Michael Yoho, Enrique R. Batista, Daikang Yan, Michael W. Rabin, Daniel S. Swetz, B. W. Renck, Gregory L. Wagner, Zachary K. Baker, Gene C. Hilton, Katrina Koehler, Kathryn G. McIntosh, Douglas A. Bennett, M. H. Carpenter, Joel N. Ullom, M. P. Croce, M. Caffrey, Carl D. Reintsema, J. Imrek, Marianne P. Wilkerson, Abigail L. Wessels, S. E. Kossmann, R. H. Cantor, Daniel Schmidt, John A. B. Mates, and Kelsey M. Morgan
- Subjects
Chemical imaging ,Materials science ,Pixel ,business.industry ,Detector ,Hyperspectral imaging ,Condensed Matter Physics ,01 natural sciences ,Multiplexing ,Atomic and Molecular Physics, and Optics ,Synchrotron ,010305 fluids & plasmas ,law.invention ,law ,0103 physical sciences ,Optoelectronics ,General Materials Science ,Transition edge sensor ,010306 general physics ,business ,Microwave - Abstract
We are developing an imaging capability (“Hyperspectral X-ray Imaging”) for mapping chemical information (molecular formula, phase, oxidation state, hydration) that is based on ultra-high-resolution X-ray emission spectroscopy with large transition-edge sensor microcalorimeter arrays in the scanning electron microscope. By combining microcalorimeter arrays with hundreds of pixels, high-bandwidth microwave frequency-division multiplexing, and fast digital electronics for near real-time data processing, our goal is to enable measurements using laboratory-scale instrumentation rather than synchrotron beamlines. Our application focus here is on mapping the chemical form of uranium compounds on the nanoscale. We will present our approach to developing the Hyperspectral X-ray Imaging capability, progress toward a 128-pixel microwave multiplexed X-ray fluorescence instrument at LANL, and the path to high-throughput nanoscale chemical mapping.
- Published
- 2020
32. Expanding the potential of redox carriers for flow battery applications
- Author
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Ping Yang, Ivan A. Popov, Gabriel A. Andrade, Benjamin L. Davis, Celia R. Federico, Enrique R. Batista, and Rangachary Mukundan
- Subjects
Materials science ,Renewable Energy, Sustainability and the Environment ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Redox ,Flow battery ,0104 chemical sciences ,Metal ,chemistry.chemical_compound ,Nickel ,chemistry ,visual_art ,visual_art.visual_art_medium ,Dimethylformamide ,General Materials Science ,Differential pulse voltammetry ,Solubility ,0210 nano-technology ,Acetonitrile - Abstract
Using theoretical modeling to guide our approach, substituents were selected to improve the negative and positive potentials associated with a representative metal-based redox carrier, a phenyl spaced nickel bispicolinamide complex, [Ni(bpb)], 1. To broaden the cell potential, electron donating groups were selected and installed on the pyridyl moieties, [Ni(bpb-(NMe2)2)], 2, while electron withdrawing groups were incorporated on the phenyl linker, [Ni(bpb-R)] (R = –F, –CF3, and –NO2), 3–5. Our model predicts an increase of ∼300 mV and ∼500 mV for the first and second negative waves of Ni(bpb-NMe2), 2, and up to ∼330 mV and ∼210 mV increase to the first and second positive waves in 3–5. The modeled complexes were synthesized in good yields using a modification of the literature procedure. Due to limited solubility, the differential pulse voltammetry was measured on complexes 2–5 using a drop cast technique. Comparison of the observed and predicted potentials is discussed in acetonitrile (MeCN) and dimethylformamide (DMF) solvents.
- Published
- 2020
33. Comparison of tetravalent cerium and terbium ions in a conserved, homoleptic imidophosphorane ligand field
- Author
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Henry S. La Pierre, John Bacsa, Ivan A. Popov, Thaige P. Gompa, Enrique R. Batista, Ping Yang, Arun Ramanathan, Dominic R. Russo, and Natalie T. Rice
- Subjects
Ligand field theory ,Lanthanide ,Crystallography ,chemistry.chemical_compound ,chemistry ,Covalent bond ,Ligand ,chemistry.chemical_element ,Terbium ,General Chemistry ,Homoleptic ,Isostructural ,Natural bond orbital - Abstract
A redox pair of Ce4+ and Ce3+ complexes has been prepared that is stabilized by the [(NP(1,2-bis-tBu-diamidoethane)(NEt2))]1− ligand. Since these complexes are isostructural to the recently reported isovalent terbium analogs, a detailed structural and spectroscopic comparative analysis was pursued via Voronoi–Dirichlet polyhedra analysis, UV-vis-NIR, L3-edge X-ray absorption near edge spectroscopy (XANES), cyclic voltammetry, and natural transitions orbital (NTO) analysis and natural bond orbital (NBO) analysis. The electrochemical studies confirm previous theoretical studies of the redox properties of the related complex [K][Ce3+(NP(pip)3)4] (pip = piperidinyl), 1-Ce(PN). Complex 1-Ce(PN*) presents the most negative Epc of −2.88 V vs. Fc/Fc+ in THF of any cerium complex studied electrochemically. Likewise 1-Tb(PN*) has the most negative Epc for electrochemically interrogated terbium complexes at −1.79 V vs. Fc/Fc+ in THF. Complexes 1-Ce(PN*) and 2-Ce(PN*) were also studied by L3-edge X-ray absorption near edges spectroscopy (XANES) and a comparison to previously reported spectra for 1-Tb(PN*), 2-Tb(PN*), 1-Ce(PN), and, [Ce4+(NP(pip)3)4], 2-Ce(PN), demonstrates similar nf values for all the tetravalent lanthanide complexes. According to the natural bond orbital analysis, a greater covalent character of the M–L bonds is found in 2-Ce(PN*) than in 1-Ce(PN*), in agreement with the shorter Ce–N bonds in the tetravalent counterpart. The greater contribution of Ce orbitals in the Ce–N bonding and, specifically, the higher participation of 4f electrons accounts for the stronger covalent interactions in 2-Ce(PN*) as compared to 2-Tb(PN*).
- Published
- 2020
34. An Allyl Uranium(IV) Sandwich Complex: Are ϕ Bonding Interactions Possible?
- Author
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Ivan A. Popov, Brennan S. Billow, Stephanie H. Carpenter, Enrique R. Batista, James M. Boncella, Aaron M. Tondreau, and Ping Yang
- Subjects
Organic Chemistry ,General Chemistry ,Catalysis - Abstract
A method to explore head-to-head ϕ back-bonding from uranium f-orbitals into allyl π* orbitals has been pursued. Anionic allyl groups were coordinated to uranium with tethered anilide ligands, then the products were investigated by using NMR spectroscopy, single-crystal XRD, and theoretical methods. The (allyl)silylanilide ligand, N-((dimethyl)prop-2-enylsilyl)-2,6-diisopropylaniline (LH), was used as either the fully protonated, singly deprotonated, or doubly deprotonated form, thereby highlighting the stability and versatility of the silylanilide motif. A free, neutral allyl group was observed in UI
- Published
- 2022
35. Isolation and characterization of a californium metallocene
- Author
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William J. Evans, Conrad A. P. Goodwin, Joseph M. Sperling, Thomas E. Albrecht-Schönzart, Jing Su, Stosh A. Kozimor, Lauren M. Stevens, Justin C. Wedal, Ping Yang, Frankie D. White, Zachary R. Jones, Sasha F. Briscoe, Alyssa N. Gaiser, Cory J. Windorff, Enrique R. Batista, Andrew J. Gaunt, Joseph W. Ziller, Brian L. Scott, Nickolas H. Anderson, Michael R. James, John D. Auxier, Justin N. Cross, Tener F. Jenkins, and Michael T. Janicke
- Subjects
chemistry.chemical_compound ,Crystallography ,Multidisciplinary ,Valence (chemistry) ,chemistry ,Chemical bond ,Bent metallocene ,chemistry.chemical_element ,Molecule ,Ionic bonding ,Californium ,Isostructural ,Organometallic chemistry - Abstract
Californium (Cf) is currently the heaviest element accessible above microgram quantities. Cf isotopes impose severe experimental challenges due to their scarcity and radiological hazards. Consequently, chemical secrets ranging from the accessibility of 5f/6d valence orbitals to engage in bonding, the role of spin–orbit coupling in electronic structure, and reactivity patterns compared to other f elements, remain locked. Organometallic molecules were foundational in elucidating periodicity and bonding trends across the periodic table1–3, with a twenty-first-century renaissance of organometallic thorium (Th) through plutonium (Pu) chemistry4–12, and to a smaller extent americium (Am)13, transforming chemical understanding. Yet, analogous curium (Cm) to Cf chemistry has lain dormant since the 1970s. Here, we revive air-/moisture-sensitive Cf chemistry through the synthesis and characterization of [Cf(C5Me4H)2Cl2K(OEt2)]n from two milligrams of 249Cf. This bent metallocene motif, not previously structurally authenticated beyond uranium (U)14,15, contains the first crystallographically characterized Cf–C bond. Analysis suggests the Cf–C bond is largely ionic with a small covalent contribution. Lowered Cf 5f orbital energy versus dysprosium (Dy) 4f in the colourless, isoelectronic and isostructural [Dy(C5Me4H)2Cl2K(OEt2)]n results in an orange Cf compound, contrasting with the light-green colour typically associated with Cf compounds16–22.
- Published
- 2021
36. Electronic Structure and Spectroscopy of f-Element Tris(cyclopentadienyl) Complexes
- Author
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Jing Su, Enrique R. Batista, and Ping Yang
- Published
- 2021
37. First-principles modeling of conductivity at the (001), (110), and (111) SrTiO3/LaAlO3 heterointerfaces
- Author
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Enrique R. Batista, Gaoxue Wang, Ping Yang, and David Gustavo Gonzalez
- Subjects
Materials science ,Condensed matter physics ,Plane (geometry) ,Fermi level ,Oxide ,Heterojunction ,Electron ,Conductivity ,symbols.namesake ,chemistry.chemical_compound ,chemistry ,Monolayer ,symbols ,Electrical conductor - Abstract
The complex polar oxide heterojunction of ${\mathrm{SrTiO}}_{3}/{\mathrm{LaAlO}}_{3}$ (STO/LAO) is of great interest due to the emergent physical phenomena observed at the interface. STO and LAO separately are wide band-gap insulators. However, upon joining them at the 001, 110, and 111 crystallographic planes, the interface undergoes a transition to a conductive state. Although first-principles modeling of the 001 plane interface has been widely studied, there is a lack of reports regarding the 110 and 111. This paper expands the theoretical model of the STO/LAO heterointerface to the three crystallographic planes (001, 110, and 111) where the conductivity has been experimentally reported. The calculations showed that whereas at the 001 interface the conductivity appears at a critical thickness of 4 monolayers of LAO, the 110 and 111 planes have no clear critical thickness; these two interfaces were always conductive. Nevertheless, the number of conductive electrons per unit cell increases with the thickness of the LAO layer in the 110 and 111 interfaces. This is related to the energy levels downshifting due to the electrostatic potential buildup (which was in the opposite direction respect to the 001 interface), increasing the number of conductive sates below the Fermi level. Given the absence of a critical thickness and the fact that chemical intermixing and oxygen vacancies at the interface were not considered, the main mechanism responsible for the conductivity in the 110 and 111 planes was attributed to the large structure reconstruction that locally changes the energy levels at the interface causing charge transfer and accumulation at the layers close to the interface.
- Published
- 2021
38. Screening of metal complexes and organic solvents using the COSMOSAC-LANL model to enhance the energy density in a non-aqueous redox flow cell: an insight into the solubility
- Author
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Anwesa Karmakar, Enrique R. Batista, Ping Yang, and Rangachary Mukundan
- Subjects
Activity coefficient ,Aqueous solution ,Materials science ,Transition metal ,Implicit solvation ,Enthalpy of fusion ,Solvation ,General Physics and Astronomy ,Thermodynamics ,Physical and Theoretical Chemistry ,Solubility ,Dilution - Abstract
In this paper, we have proposed a first-principles methodology to screen transition metal complexes against a particular organic solvent and organic solvents against a particular transition metal complex based on their solubility information without the knowledge of heat of fusion and melting temperature. The energy density of a non-aqueous redox flow cell directly depends on the solubility of the redox active species in the non-aqueous medium. We have used the “COSMOSAC-LANL” activity coefficient model (A. Karmakar, R. Mukundan, P. Yang and E. R. Batista, RSC Adv., 2019, 18506–18526; A. Karmakar and R. Mukundan, Phys. Chem. Chem. Phys., 2019, 19667–19685) which is based on first-principles COSMO calculations where the microscopic information is passed to the macroscopic world via a dielectric continuum solvation model, followed by a post-statistical thermodynamic treatment of the self-consistent properties of the solute particle to calculate the solubility. To model the activity coefficient at infinite dilution for the binary mixtures, a 3-suffix Margules (3sM) function is introduced for the quantitative estimation of the asymmetric interactions and, for the combinatorial term, the Staverman–Guggenheim (SG) form is used. The new activity coefficient model is separately called the “LANL” activity coefficient model. The metal complex and the organic solvent have been treated as a simple binary mixture. The present model has been applied to a set of 14 different organic solvents and 16 different transition metal complexes. Using the new LANL activity coefficient model in combination with the ADF-COSMOSAC-2013 model, we have shown how one can improve the solubility of a transition metal complex in an organic solvent. We applied our model to screen 84 binary mixtures to predict the compatible pair of redox active species and organic solvent to increase the energy density. The solvation mechanism of the transition metal complexes in the organic solvents was obtained using the new model. The results have been compared with the experimental and theoretical results where they are available.
- Published
- 2021
39. Excess Electrons on Reduced AnO2 (111) Surfaces (An = Th, U, Pu) and Their Impacts on Catalytic Water Splitting
- Author
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Enrique R. Batista, Ping Yang, and Gaoxue Wang
- Subjects
Materials science ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,Electron ,Actinide ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Oxygen ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Catalysis ,Metal ,General Energy ,chemistry ,visual_art ,visual_art.visual_art_medium ,Water splitting ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
Excess electrons from intrinsic oxygen vacancies play a key role in the surface chemistry and catalytic properties of metal oxides. This effect is particularly critical in actinide dioxides (AnO2),...
- Published
- 2019
40. 'Sweeping' Ortho Substituents Drive Desolvation and Overwhelm Electronic Effects in Nd3+ Chelation: A Case of Three Aryldithiophosphinates
- Author
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Lei Xu, Ping Yang, Jing Chen, Ning Pu, Jenifer C. Shafer, Chao Xu, Enrique R. Batista, Taoxiang Sun, and Jing Su
- Subjects
Lanthanide ,Trifluoromethyl ,010405 organic chemistry ,Ligand ,Chemistry ,010402 general chemistry ,01 natural sciences ,Medicinal chemistry ,0104 chemical sciences ,Inorganic Chemistry ,chemistry.chemical_compound ,Group (periodic table) ,Electronic effect ,Chelation ,Desolvation ,Physical and Theoretical Chemistry - Abstract
Bis[o-(trifluoromethyl)phenyl]dithiophosphinate is a sulfur-donating ligand capable of providing the largest reported trivalent lanthanide (Ln3+)–actinide (An3+) group separation factors. Literatur...
- Published
- 2019
41. Enthalpies of formation and phase stability relations of USi, U3Si5 and U3Si2
- Author
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Andrew T. Nelson, C. K. Chung, Ping Yang, Anna Shelyug, Joshua T. White, Xiaofeng Guo, Hongwu Xu, Hakim Boukhalfa, Enrique R. Batista, Gaoxue Wang, Tashiema L. Wilson, Artaches Migdisov, Robert Roback, and Alexandra Navrotsky
- Subjects
Nuclear and High Energy Physics ,Materials science ,Intermetallic ,Thermodynamics ,02 engineering and technology ,Calorimetry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Standard enthalpy of formation ,010305 fluids & plasmas ,Tetragonal crystal system ,Nuclear Energy and Engineering ,0103 physical sciences ,General Materials Science ,Density functional theory ,Chemical stability ,Binary system ,0210 nano-technology ,Phase diagram - Abstract
U–Si intermetallic compounds have drawn great attention due to their potential application as nuclear fuels. However, the thermodynamic properties and phase equilibria of this binary system from ambient to high temperature conditions are not fully understood. Via high temperature oxidative drop calorimetry and detailed characterization of the initial and final phases, we have experimentally determined the standard enthalpies of formation of USi and U3Si5.07 at 298 K to be −43.2 ± 6.2 and −43.8 ± 9.0 kJ/mol·atom, respectively. The energetics of the tetragonal USi (t-USi, space group I4/mmm) phase has also been calculated with Density Functional Theory (DFT) for the first time. Combining the obtained formation enthalpies with the heat capacities measured previously, we assessed the thermodynamic stability of t-USi relative to a phase assemblage of two other U–Si phases, U3Si5.07 and U3Si2, from ambient temperature to 1200 K. The tetragonal USi is thermodynamically more stable than U3Si5.07 + U3Si2, which supports previously published phase diagram (H. Okamoto and T. Massalski, 1990 [1]): specifically, at least one stable USi phase exists when the U content is 50 at.%. Further thermodynamic and phase equilibrium studies are needed for a more comprehensive understanding of the U–Si system across broader compositional and temperature ranges.
- Published
- 2019
42. [Am(C 5 Me 4 H) 3 ]: An Organometallic Americium Complex
- Author
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Conrad A. P. Goodwin, Jing Su, Thomas E. Albrecht‐Schmitt, Anastasia V. Blake, Enrique R. Batista, Scott R. Daly, Stefanie Dehnen, William J. Evans, Andrew J. Gaunt, Stosh A. Kozimor, Niels Lichtenberger, Brian L. Scott, and Ping Yang
- Subjects
General Medicine - Published
- 2019
43. [Am(C 5 Me 4 H) 3 ]: An Organometallic Americium Complex
- Author
-
Scott R. Daly, Andrew J. Gaunt, Thomas E. Albrecht-Schmitt, William J. Evans, Enrique R. Batista, Stosh A. Kozimor, Brian L. Scott, Stefanie Dehnen, Jing Su, Niels Lichtenberger, Ping Yang, Conrad A. P. Goodwin, and Anastasia V. Blake
- Subjects
Materials science ,actinides ,organometallic complexes ,structure elucidation ,Near-infrared spectroscopy ,chemistry.chemical_element ,Americium ,General Chemistry ,Actinide ,cyclopentadienyl ligands ,Catalysis ,americium ,chemistry ,Yield (chemistry) ,Physical chemistry ,Density functional theory ,Wave function ,Spectroscopy - Abstract
We report the small-scale synthesis, isolated yield, single-crystal X-ray structure, 1H NMR solution spectroscopy /solid-state UV/Vis-nIR spectroscopy, and density functional theory (DFT)/ab initio wave function theory calculations on an Am3+ organometallic complex, [Am(C5Me4H)3] (1). This constitutes the first quantitative data on Am−C bonding in a molecular species.
- Published
- 2019
44. Linked Picolinamide Nickel Complexes as Redox Carriers for Nonaqueous Flow Batteries
- Author
-
Ivan A. Popov, Enrique R. Batista, Sandip Maurya, Benjamin L. Davis, Terry Chu, Rangachary Mukundan, Brian L. Scott, Ping Yang, and Gabriel A. Andrade
- Subjects
General Chemical Engineering ,Flow (psychology) ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Redox ,0104 chemical sciences ,Nickel ,General Energy ,chemistry ,Negative charge ,Environmental Chemistry ,Moiety ,lipids (amino acids, peptides, and proteins) ,General Materials Science ,0210 nano-technology - Abstract
The use of nickel complexes utilizing non-innocent ligands based on picolinamide to function as redox carriers in flow batteries was explored. The picolinamide moiety was linked together with -CH2 CH2 - (bpen), -CH2 CH2 CH2 - (bppn), and -C6 H4 - (bpb) moieties, resulting in two, three, and four quasi-reversible waves, respectively, for the nickel complexes and >3 V difference between the outermost positive and negative waves. The redox events were theoretically modelled for each complex, showing excellent agreement (
- Published
- 2019
45. Soft-donor dipicolinamide derivatives for selective actinide(<scp>iii</scp>)/lanthanide(<scp>iii</scp>) separation: the role of S- vs. O-donor sites
- Author
-
Teresa M. Eaton, Konstantinos E. Papathanasiou, Christopher J. Dares, Konstantinos Kavallieratos, David Dan, Jiwen Jian, Jing Su, Ping Yang, Ingrid Lehman-Andino, Thomas E. Albrecht-Schmitt, Enrique R. Batista, and John K. Gibson
- Subjects
chemistry.chemical_classification ,Lanthanide ,Ligand ,Complex formation ,Extraction (chemistry) ,Metals and Alloys ,General Chemistry ,Actinide ,Medicinal chemistry ,Catalysis ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry ,Materials Chemistry ,Ceramics and Composites ,Selectivity ,Thioamide - Abstract
Selectivity for An(iii) vs. Ln(iii) binding and extraction using dipicolinamide analogs containing the C[double bond, length as m-dash]O vs. C[double bond, length as m-dash]S groups was investigated in solution and the gas-phase, and by DFT calculations. The results show higher selectivity for complex formation and extraction for Am(iii) vs. Eu(iii) for the softer dithioamide vs. the diamide ligand, while in CH3CN the diamide binds more strongly than the thioamide to several Ln(iii), forming 1 : 1 complexes.
- Published
- 2019
46. Halide anion discrimination by a tripodal hydroxylamine ligand in gas and condensed phases
- Author
-
Thibault Cheisson, Jiwen Jian, Michael R. Gau, Jing Su, Patrick J. Carroll, John K. Gibson, Enrique R. Batista, Eric J. Schelter, Teresa M. Eaton, and Ping Yang
- Subjects
Chemical Physics ,Collision-induced dissociation ,Ligand ,Electrospray ionization ,General Physics and Astronomy ,Halide ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Medicinal chemistry ,0104 chemical sciences ,Hydrogen halide ,chemistry.chemical_compound ,Engineering ,Hydroxylamine ,chemistry ,Physical Sciences ,Chemical Sciences ,Molecule ,Density functional theory ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
Electrospray ionization of solutions containing a tripodal hydroxylamine ligand, H3TriNOx ([((2-tBuNOH)C6H4CH2)3N]) denoted as L, and a hydrogen halide HX: HCl, HBr and/or HI, yielded gas-phase anion complexes [L(X)]- and [L(HX2)]-. Collision induced dissociation (CID) of mixed-halide complexes, [L(HXaXb)]-, indicated highest affinity for I- and lowest for Cl-. Structures and energetics computed by density functional theory are in accord with the CID results, and indicate that the gas-phase binding preference is a manifestation of differing stabilities of the HX molecules. A high halide affinity of [L(H)]+ in solution was also demonstrated, though with a highest preference for Cl- and lowest for I-, the opposite observation of, but not in conflict with, what is observed in gas phase. The results suggest a connection between gas- and condensed-phase chemistry and computational approaches, and shed light on the aggregation and anion recognition properties of hydroxylamine receptors.
- Published
- 2019
47. Solubility model of metal complex in ionic liquids from first principle calculations
- Author
-
Enrique R. Batista, Anwesa Karmakar, Rangachary Mukundan, and Ping Yang
- Subjects
Chemistry ,General Chemical Engineering ,Solvation ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Ion ,Solvent ,Metal ,chemistry.chemical_compound ,visual_art ,Ionic liquid ,visual_art.visual_art_medium ,Molecule ,Physical chemistry ,Solubility ,0210 nano-technology ,Acetonitrile - Abstract
A predictive model based on first principles calculations has been proposed to study the solid–liquid equilibria comprising of metal complexes and ionic liquids. The model is based on first principle COSMO calculation followed by post statistical thermodynamical treatment of self-consistent properties of solute and solvent molecules. The metal complex and ionic liquid have been treated as a simple binary mixture. The ionic liquid has been treated here as a single intact molecule. The experimentally observed dual-solute relationship between the ionic liquid and redox active species in presence of a third organic solvent has been established using our model in this work. Within the model, the dual-solute relationship appeared as a simple Gibbs–Duhem relationship between these two species at ambient condition. The dual-solute relationship between the metal complex (V(acac)3, Cr(acac)3 and Mn(acac)3) and ionic liquid ([Tea][BF4]) has been validated by calculating the Gibbs–Duhem relationship, xsolute vs. xsolvent(IL) and 1/γsolute vs. xsolvent(IL) plots. The present model has been applied to a set of ionic liquids, metal complexes and organic solvent (acetonitrile) for which experimental study has been done. The solvation mechanism of the metal complexes in those ionic liquids was obtained using the model. According to our findings, the ionic liquid containing imidazolium cation and [NTf2]− anion is appeared as a suitable solvent for the non-aqueous redox flow cell. We have compared our results with the already reported experimental results where they were available for the non-aqueous solvents.
- Published
- 2019
48. (Invited, Digital Presentation) Tuning the Electrodeposition of Actinides in Molten Alkali Halide Salts
- Author
-
Molly M MacInnes, Kristen A Pace, Ida M DiMucci, Nickolas H Anderson, Benjamin W Stein, Stosh Kozimor, Francisca R Rocha, Zachary R Jones, Veronika Mocko, Enrique R Batista, Cecilia Eiroa-Lledo, Maksim Y Livshits, Jennifer N Wacker, Karah E Knope, and Ping Yang
- Abstract
Molten salts have found use as solvents in numerous applications including nuclear reactors, batteries, and the extraction and purification of various metals. Unfortunately, understanding of the chemistry of molten salt solutions is limited. In this presentation we explore the use of molten salts as a testbed for understanding both outer and inner coordination sphere effects on dissolved metal ions. The electron transfer reactions available to lanthanides (Eu3+, Sm3+, and Yb3+) and actinides (U3+, U4+, and Th4+) were explored in a series of alkali and alkaline earth halide salts. We present electrochemical data that demonstrate significant shifts in the reduction potentials of these metal ions as a function of the anion and cation identities of the molten salt solvent. We hypothesize that effects on the reduction potential of these metals come from two sources: (1) the primary coordination sphere and (2) the secondary coordination sphere. The influence from the primary coordination sphere is dominated by the degree of covalency in the coordination bonds between the Lnn+ and Ann+ cations and the molten salt anions. The influence of the secondary coordination sphere is dominated by the electron-withdrawing character of the salt cations. EXAFS data and computational results that support these hypotheses are presented. Further, we provide insight into electrodeposition of the An0 metals under these conditions and highlight temperature and molten salt effects that influence these electrodepositions. Specifically, we propose that increased mobility of solid-state atoms at high temperature (> 800°C) influence the properties of electrodeposited metals.
- Published
- 2022
49. Impact of Ligand Substitutions on Multielectron Redox Properties of Fe Complexes Supported by Nitrogenous Chelates
- Author
-
Enrique R. Batista, Ivan A. Popov, Benjamin L. Davis, Ping Yang, Nada Mehio, Rangachary Mukundan, and Terry Chu
- Subjects
High energy ,010405 organic chemistry ,Ligand ,Chemistry ,General Chemical Engineering ,Design elements and principles ,General Chemistry ,Electrolyte ,010402 general chemistry ,01 natural sciences ,Combinatorial chemistry ,Redox ,Article ,0104 chemical sciences ,lcsh:Chemistry ,Solvent ,lcsh:QD1-999 ,Chelation ,Electrochemical window - Abstract
Redox flow batteries (RFBs) have recently been recognized as a potentially viable technology for scalable energy storage. To take full advantage of RFBs, one possible approach for achieving high energy densities is to maximize a number of redox events by utilizing charge carriers capable of multiple one-electron transfers within the electrochemical window of solvent. However, past efforts to develop more efficient electrolytes for nonaqueous RFBs have mostly been empirical. In this manuscript, we shed light on design principles by theoretically investigating the effects of systematically substituting pyridyl moieties with imine ligands within a series of Fe complexes with some experimental validation. We found that such replacement is an effective strategy for reducing the molecular weight-to-charge ratios of these complexes. Simultaneously, calculations suggest that the reduction potentials and ligand-based redox activity of such substituted N-heterocyclic Fe compounds might be maintained within their +4 → -1 charge states. Additionally, by theoretically examining the role of coordination geometry, vis-à-vis reducing the number of redox noninnocent ligands within the first coordination sphere, we have demonstrated that Fe complexes with one such ligand were also capable of supporting multielectron reduction events and exhibited reduction potentials similar to their parent analogs supported by two or three of the same multidentate ligands. However, some differences in redox nature within the lower (+2 → -1) charge states were also noticed. Specifically, complexes containing two bidentate ligands, or one tridentate ligand, exhibited ligand-based reductions, whereas compounds with one bidentate ligand exhibited metal-centered reductions. The current results pave the way toward the design of the next-generation of Fe complexes with lower molecular weights and greater stored energy for redox flow batteries.
- Published
- 2018
50. Complexation of Lanthanides and Heavy Actinides with Aqueous Sulfur-Donating Ligands
- Author
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Peter R. Zalupski, Corwin H. Booth, Liane M. Moreau, Travis S. Grimes, Ivan A. Popov, Colt R. Heathman, Kurt F. Smith, Enrique R. Batista, Rebecca J. Abergel, Ping Yang, Nathan P. Bessen, and Jenifer C. Shafer
- Subjects
chemistry.chemical_classification ,Lanthanide ,Aqueous solution ,010405 organic chemistry ,Inorganic chemistry ,chemistry.chemical_element ,Americium ,Actinide ,010402 general chemistry ,01 natural sciences ,Micelle ,0104 chemical sciences ,Coordination complex ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Thioether ,Stability constants of complexes ,Physical and Theoretical Chemistry - Abstract
The separation of trivalent lanthanides and actinides is challenging because of their similar sizes and charge densities. S-donating extractants have shown significant selectivity for trivalent actinides over lanthanides, with single-stage americium/lanthanide separation efficiencies for some thiol-based extractants reported at >99.999%. While such separations could transform the nuclear waste management landscape, these systems are often limited by the hydrolytic and radiolytic stability of the extractant. Progress away from thiol-based systems is limited by the poorly understood and complex interactions of these extractants in organic phases, where molecular aggregation and micelle formation obfuscates assessment of the metal-extractant coordination environment. Because S-donating thioethers are generally more resistant to hydrolysis and oxidation and the aqueous phase coordination chemistry is anticipated to lack complications brought on by micelle formation, we have considered three thioethers, 2,2'-thiodiacetic acid (TDA), (2R,5S)-tetrahydrothiophene-2,5-dicarboxylic acid, and 2,5-thiophenedicarboxylic acid (TPA), as possible trivalent actinide selective reagents. Formation constants, extended X-ray absorption fine structure spectroscopy, and computational studies were completed for thioether complexes with a variety of trivalent lanthanides and actinides including Nd, Eu, Tb, Am, Cm, Bk, and Cf. TPA was found to have moderately higher selectivity for the actinides because of its ability to bind actinides in a different manner than lanthanides, but the utility of TPA is limited by poor water solubility and high rigidity. While significant competition with water for the metal center limits the efficacy of aqueous-based thioethers for separations, the characterization of these solution-phase, S-containing lanthanide and actinide complexes is the most comprehensively available in the literature to date. This is due to the breadth of lanthanides and actinides considered as well as the techniques deployed and serves as a platform for the further development of S-containing reagents for actinide separations. Additionally, this paper reports on the first bond lengths for Cf and Bk with a neutral S donor.
- Published
- 2021
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