138 results on '"Enrique R. Batista"'
Search Results
2. 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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3. 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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4. 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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5. 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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6. 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
7. 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...
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- 2021
8. 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
9. 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
10. 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.
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- 2020
11. 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
12. 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
13. 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.
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- 2020
14. δ and φ back-donation in AnIV metallacycles
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Morgan P. Kelley, Ping Yang, Julie Jung, Enrique R. Batista, and Ivan A. Popov
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Multidisciplinary ,010405 organic chemistry ,Chemistry ,Ligand ,Science ,General Physics and Astronomy ,General Chemistry ,010402 general chemistry ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,0104 chemical sciences ,Bond length ,Metal ,Crystallography ,Atomic orbital ,Group (periodic table) ,visual_art ,visual_art.visual_art_medium ,lcsh:Q ,lcsh:Science - Abstract
In all known examples of metal–ligand (M–L) δ and φ bonds, the metal orbitals are aligned to the ligand orbitals in a “head-to-head” or “side-to-head” fashion. Here, we report two fundamentally new types of M–L δ and φ interactions; “head-to-side” δ and “side-to-side” φ back-bonding, found in complexes of metallacyclopropenes and metallacyclocumulenes of actinides (Pa–Pu) that makes them distinct from their corresponding Group 4 analogues. In addition to the known Th and U complexes, our calculations include complexes of Pa, Np, and Pu. In contrast with conventional An–C bond decreasing, due to the actinide contraction, the An–C distance increases from Pa to Pu. We demonstrate that the direct L–An σ and π donations combined with the An–L δ or φ back-donations are crucial in explaining this non-classical trend of the An–L bond lengths in both series, underscoring the significance of these δ/φ back-donation interactions, and their importance for complexes of Pa and U in particular.
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- 2020
15. Expanding the potential of redox carriers for flow battery applications
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Ping Yang, Ivan A. Popov, Gabriel A. Andrade, Benjamin L. Davis, Celia R. Federico, Enrique R. Batista, and Rangachary Mukundan
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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.
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- 2020
16. Comparison of tetravalent cerium and terbium ions in a conserved, homoleptic imidophosphorane ligand field
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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
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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*).
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- 2020
17. Isolation and characterization of a californium metallocene
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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
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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
18. First-principles modeling of conductivity at the (001), (110), and (111) SrTiO3/LaAlO3 heterointerfaces
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Enrique R. Batista, Gaoxue Wang, Ping Yang, and David Gustavo Gonzalez
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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
19. Excess Electrons on Reduced AnO2 (111) Surfaces (An = Th, U, Pu) and Their Impacts on Catalytic Water Splitting
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Enrique R. Batista, Ping Yang, and Gaoxue Wang
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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
20. 'Sweeping' Ortho Substituents Drive Desolvation and Overwhelm Electronic Effects in Nd3+ Chelation: A Case of Three Aryldithiophosphinates
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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
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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
21. [Am(C 5 Me 4 H) 3 ]: An Organometallic Americium Complex
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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
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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
22. Linked Picolinamide Nickel Complexes as Redox Carriers for Nonaqueous Flow Batteries
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Ivan A. Popov, Enrique R. Batista, Sandip Maurya, Benjamin L. Davis, Terry Chu, Rangachary Mukundan, Brian L. Scott, Ping Yang, and Gabriel A. Andrade
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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
23. Soft-donor dipicolinamide derivatives for selective actinide(<scp>iii</scp>)/lanthanide(<scp>iii</scp>) separation: the role of S- vs. O-donor sites
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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
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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
24. Halide anion discrimination by a tripodal hydroxylamine ligand in gas and condensed phases
- Author
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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
25. Solubility model of metal complex in ionic liquids from first principle calculations
- Author
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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
26. Impact of Ligand Substitutions on Multielectron Redox Properties of Fe Complexes Supported by Nitrogenous Chelates
- Author
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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
27. 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
28. SCC-DFTB Parameters for Fe-C Interactions
- Author
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Marc J. Cawkwell, Elena Jakubikova, Néstor F. Aguirre, Enrique R. Batista, Chang Liu, and Ping Yang
- Subjects
Set (abstract data type) ,Chemistry ,Transferability ,Thermodynamics ,Physical and Theoretical Chemistry - Abstract
We present an optimized density-functional tight-binding (DFTB) parameterization for iron-based complexes based on the popular trans3d set of parameters. The transferability of the original and opt...
- Published
- 2020
29. Analysis of the thermodynamic stability of ThO2 and UO2 surfaces in the presence of surfactant ligands
- Author
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Gaoxue Wang, David Gustavo Gonzalez, Enrique R. Batista, and Ping Yang
- Subjects
Pulmonary surfactant ,Chemistry ,Physical chemistry ,Chemical stability - Published
- 2020
30. Computational screening of two-dimensional coatings for semiconducting photocathodes
- Author
-
Ping Yang, Gaoxue Wang, and Enrique R. Batista
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,Graphene ,business.industry ,Nitride ,engineering.material ,law.invention ,chemistry.chemical_compound ,chemistry ,Coating ,law ,engineering ,Graphane ,Optoelectronics ,General Materials Science ,Quantum efficiency ,Work function ,MXenes ,business ,Visible spectrum - Abstract
Alkali-based semiconducting photocathodes, due to their high quantum efficiency (QE) in the visible light spectrum, are promising candidates to replace traditional metal photocathodes for high-brightness beam applications such as x-ray free electron lasers (XFELs). However, they suffer from rapid degradation which significantly limits their operational lifetimes. Coating them with two-dimensional (2D) materials has been proposed as a possible avenue to prevent the degradation. Ideally, the 2D coating layer should not increase the work function of semiconducting photocathodes, thus maintaining the high QE of semiconducting photocathodes in visible light. Herein, we report a computational screening of over 4000 2D materials in the Computational 2D Materials Database (C2DB). The assessment of their potential to be good coating layers is based on their effects to the surface electronic properties. We discover several candidate materials that are even capable of decreasing the work function of semiconducting photocathodes. Some of the experimentally synthesized 2D materials, such as hydrogenated graphene (graphane) and several hydroxylated transition metal carbides/nitrides (MXenes), are particularly appealing for this application.
- Published
- 2020
31. Development of Density Functional Tight-Binding Parameters Using Relative Energy Fitting and Particle Swarm Optimization
- Author
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Amanda Morgenstern, Enrique R. Batista, Néstor F. Aguirre, Marc J. Cawkwell, and Ping Yang
- Subjects
Materials science ,010304 chemical physics ,Hydrogen ,chemistry.chemical_element ,Particle swarm optimization ,01 natural sciences ,Computer Science Applications ,Organic molecules ,Tight binding ,chemistry ,Chemical physics ,0103 physical sciences ,Development (differential geometry) ,Physical and Theoretical Chemistry ,Carbon ,Relative energy - Abstract
We provide a strategy to optimize density functional tight-binding (DFTB) parameterization for the calculation of the structures and properties of organic molecules consisting of hydrogen, carbon, nitrogen, and oxygen. We utilize an objective function based on similarity measurements and the Particle Swarm Optimization (PSO) method to find an optimal set of parameters. This objective function considers not only the common DFTB descriptors of binding energies and atomic forces but also incorporates relative energies of isomers into the fitting procedure for more chemistry-driven results. The quality in the description of the binding energies and atomic forces is measured based on the Ballester similarity index and relative energies through a similarity index induced by the Levenshtein edit distance to quantify the correct energetic order of isomers. Training and testing datasets were created to include all relevant chemical functional groups. The accuracy of this strategy is assessed, and its range of applicability is discussed by comparison against our previous parameterization [A. Krishnapriyan, et al.
- Published
- 2020
32. The duality of electron localization and covalency in lanthanide and actinide metallocenes
- Author
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Richard L. Martin, Corwin H. Booth, Stefan G. Minasian, Jason M. Keith, David K. Shuh, David Clark, Tolek Tyliszczak, Enrique R. Batista, S. Chantal E. Stieber, Stosh A. Kozimor, and Danil E. Smiles
- Subjects
Delocalized electron ,Crystallography ,Chemistry ,Materials science ,Atomic orbital ,Chemical Sciences ,Density functional theory ,Strongly correlated material ,General Chemistry ,Time-dependent density functional theory ,Configuration interaction ,Ground state ,Electron localization function - Abstract
Previous magnetic, spectroscopic, and theoretical studies of cerocene, Ce(C8H8)2, have provided evidence for non-negligible 4f-electron density on Ce and implied that charge transfer from the ligands occurs as a result of covalent bonding. Strong correlations of the localized 4f-electrons to the delocalized ligand π-system result in emergence of Kondo-like behavior and other quantum chemical phenomena that are rarely observed in molecular systems. In this study, Ce(C8H8)2 is analyzed experimentally using carbon K-edge and cerium M5,4-edge X-ray absorption spectroscopies (XAS), and computationally using configuration interaction (CI) calculations and density functional theory (DFT) as well as time-dependent DFT (TDDFT). Both spectroscopic approaches provide strong evidence for ligand → metal electron transfer as a result of Ce 4f and 5d mixing with the occupied C 2p orbitals of the C8H82− ligands. Specifically, the Ce M5,4-edge XAS and CI calculations show that the contribution of the 4f1, or Ce3+, configuration to the ground state of Ce(C8H8)2 is similar to strongly correlated materials such as CeRh3 and significantly larger than observed for other formally Ce4+ compounds including CeO2 and CeCl62−. Pre-edge features in the experimental and TDDFT-simulated C K-edge XAS provide unequivocal evidence for C 2p and Ce 4f covalent orbital mixing in the δ-antibonding orbitals of e2u symmetry, which are the unoccupied counterparts to the occupied, ligand-based δ-bonding e2u orbitals. The C K-edge peak intensities, which can be compared directly to the C 2p and Ce 4f orbital mixing coefficients determined by DFT, show that covalency in Ce(C8H8)2 is comparable in magnitude to values reported previously for U(C8H8)2. An intuitive model is presented to show how similar covalent contributions to the ground state can have different impacts on the overall stability of f-element metallocenes., Unequivocal experimental evidence for carbon 2p and cerium 4f orbital mixing in cerocene, Ce(C8H8)2 is provided from carbon K-edge and Ce M5,4-edge X-ray absorption spectroscopies and corroborated with DFT and configuration interaction calculations.
- Published
- 2020
33. Advancing Chelation Chemistry for Actinium and Other +3 f-Elements, Am, Cm, and La
- Author
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Eva R. Birnbaum, Stosh A. Kozimor, Brian L. Scott, Veronika Mocko, Samantha K. Cary, Ping Yang, Kevin D. John, Amanda Morgenstern, Benjamin W. Stein, Maryline G. Ferrier, Enrique R. Batista, Sharon E. Bone, and Juan S. Lezama Pacheco
- Subjects
Actinium ,Inorganic chemistry ,Binding pocket ,chemistry.chemical_element ,010402 general chemistry ,Ligands ,01 natural sciences ,Biochemistry ,Catalysis ,Coordination complex ,Colloid and Surface Chemistry ,Organophosphorus Compounds ,Coordination Complexes ,Lanthanum ,Molecule ,Chelation ,Chelating Agents ,chemistry.chemical_classification ,Americium ,Extended X-ray absorption fine structure ,Molecular Structure ,Extramural ,General Chemistry ,0104 chemical sciences ,chemistry ,Curium ,Radiopharmaceuticals - Abstract
A major chemical challenge facing implementation of 225Ac in targeted alpha therapy-an emerging technology that has potential for treatment of disease-is identifying an 225Ac chelator that is compatible with in vivo applications. It is unclear how to tailor a chelator for Ac binding because Ac coordination chemistry is poorly defined. Most Ac chemistry is inferred from radiochemical experiments carried out on microscopic scales. Of the few Ac compounds that have been characterized spectroscopically, success has only been reported for simple inorganic ligands. Toward advancing understanding in Ac chelation chemistry, we have developed a method for characterizing Ac complexes that contain highly complex chelating agents using small quantities (μg) of 227Ac. We successfully characterized the chelation of Ac3+ by DOTP8- using EXAFS, NMR, and DFT techniques. To develop confidence and credibility in the Ac results, comparisons with +3 cations (Am, Cm, and La) that could be handled on the mg scale were carried out. We discovered that all M3+ cations (M = Ac, Am, Cm, La) were completely encapsulated within the binding pocket of the DOTP8- macrocycle. The computational results highlighted the stability of the M(DOTP)5- complexes.
- Published
- 2019
34. Identification of the Formal +2 Oxidation State of Neptunium: Synthesis and Structural Characterization of {NpII[C5H3(SiMe3)2]3}1–
- Author
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Andrew J. Gaunt, David H. Woen, Stosh A. Kozimor, Michael T. Janicke, Brian L. Scott, William J. Evans, Cory J. Windorff, Jing Su, Enrique R. Batista, and Ping Yang
- Subjects
010405 organic chemistry ,Chemistry ,Neptunium ,chemistry.chemical_element ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Catalysis ,0104 chemical sciences ,Characterization (materials science) ,Ion ,Crystallography ,Colloid and Surface Chemistry ,Oxidation state ,Density functional theory ,Electron configuration ,Ground state - Abstract
We report a new formal oxidation state for neptunium in a crystallographically characterizable molecular complex, namely Np2+ in [K(crypt)][NpIICp″3] [crypt = 2.2.2-cryptand, Cp″ = C5H3(SiMe3)2]. Density functional theory calculations indicate that the ground state electronic configuration of the Np2+ ion in the complex is 5f46d1.
- Published
- 2018
35. Influence of Substituents on the Electronic Structure of Mono- and Bis(phosphido) Thorium(IV) Complexes
- Author
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Pokpong Rungthanaphatsophon, Jochen Autschbach, Charles L. Barnes, Justin R. Walensky, Enrique R. Batista, Sean P. Vilanova, Thomas J. Duignan, Alexander J. Myers, and Ping Yang
- Subjects
Trimethylsilyl ,Absorption spectroscopy ,010405 organic chemistry ,Substituent ,Thorium ,chemistry.chemical_element ,Electronic structure ,010402 general chemistry ,01 natural sciences ,Medicinal chemistry ,0104 chemical sciences ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Density functional theory ,Physical and Theoretical Chemistry ,Metallocene - Abstract
A series of metallocene thorium complexes with mono- and bis(phosphido) ligands have been investigated with varying hues: (C5Me5)2Th(Cl)[P(Mes)2] (Mes = mesityl = 2,4,6-(CH3)3C6H2; dark red-purple), (C5Me5)2Th[P(Mes)(CH3)]2 (dark red-purple), (C5Me5)2Th(CH3)[P(Mes)2] (dark red-purple), (C5Me5)2Th(CH3)[P(Mes)(SiMe3)] (orange), (C5Me5)2Th(Cl)[P(Mes)(SiMe3)] (orange), (C5Me5)2Th[P(Mes)(SiMe3)]2 (orange), and (C5Me5)2Th[PH(Mes)]2 (pale yellow). While all of these complexes bear a mesityl group on phosphorus, the electronic structure observed differs depending on the other substituent (mesityl, methyl, trimethylsilyl, or hydrogen). This sparked an investigation of the electronic structure of these complexes using 31P NMR and electronic absorption spectroscopy in concert with time-dependent density functional theory calculations.
- Published
- 2018
36. Spectroscopic and Computational Characterization of Diethylenetriaminepentaacetic Acid/Transplutonium Chelates: Evidencing Heterogeneity in the Heavy Actinide(III) Series
- Author
-
Corwin H. Booth, Rebecca J. Abergel, Morgan P. Kelley, Enrique R. Batista, Jing Su, Gauthier J.-P. Deblonde, and Ping Yang
- Subjects
Lanthanide ,Aqueous solution ,Extended X-ray absorption fine structure ,010405 organic chemistry ,chemistry.chemical_element ,General Chemistry ,Actinide ,010402 general chemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Bond length ,Berkelium ,chemistry ,Molecule ,Physical chemistry ,Density functional theory - Abstract
The chemistry of trivalent transplutonium ions (Am3+ , Cm3+ , Bk3+ , Cf3+ , Es3+ …) is usually perceived as monotonic and paralleling that of the trivalent lanthanide series. Herein, we present the first extended X-ray absorption fine structure (EXAFS) study performed on a series of aqueous heavy actinide chelates, extending past Cm. The results obtained on diethylenetriaminepentaacetic acid (DTPA) complexes of trivalent Am, Cm, Bk, and Cf show a break to much shorter metal-oxygen nearest-neighbor bond lengths in the case of Cf3+ . Corroborating those results, density functional theory calculations, extended to Es3+ , suggest that the shorter Cf-O and Es-O bonds could arise from the departure of the coordinated water molecule and contraction of the ligand around the metal relative to the other [MIII DTPA(H2 O)]2- (M=Am, Cm, Bk) complexes. Taken together, these experimental and theoretical results demonstrate inhomogeneity within the trivalent transplutonium series that has been insinuated and debated in recent years, and that may also be leveraged for future nuclear waste reprocessing technologies.
- Published
- 2018
37. A series of dithiocarbamates for americium, curium, and californium
- Author
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Brian L. Scott, Shane S. Galley, Samantha K. Cary, Ping Yang, Cayla E. Van Alstine, Stosh A. Kozimor, Frankie D. White, Veronika Mocko, Thomas E. Albrecht-Schmitt, Jing Su, Maryline G. Ferrier, and Enrique R. Batista
- Subjects
Lanthanide ,Materials science ,Series (mathematics) ,Curium ,010405 organic chemistry ,Analytical chemistry ,chemistry.chemical_element ,Californium ,Americium ,Actinide ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,chemistry - Abstract
Characterizing how actinide properties change across the f-element series is critical for improving predictive capabilities and solving many nuclear problems facing our society. Unfortunately, it is difficult to make direct comparisons across the 5f-element series because so little is known about trans-plutonium elements. Results described herein help to address this issue through isolation of An(S2CNEt2)3(N2C12H8) (Am, Cm, and Cf). These findings included the first single crystal X-ray diffraction measurements of Cm-S (mean of 2.86 ± 0.04 Å) and Cf-S (mean of 2.84 ± 0.04 Å) bond distances. Furthermore, they highlight the potential of An(S2CNEt2)3(N2C12H8) for providing a test bed for comparative analyses of actinide versus lanthanide bonding interactions.
- Published
- 2018
38. Revisiting complexation thermodynamics of transplutonium elements up to einsteinium
- Author
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Enrique R. Batista, Ping Yang, Sergey I. Sinkov, Jenifer C. Shafer, Jing Su, Morgan P. Kelley, Nathan P. Bessen, Matthew Urban, and Gregg J. Lumetta
- Subjects
010405 organic chemistry ,Chemistry ,Metals and Alloys ,chemistry.chemical_element ,General Chemistry ,Actinide ,010402 general chemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Computational chemistry ,Einsteinium ,Materials Chemistry ,Ceramics and Composites - Abstract
Literature casts einsteinium as a departure from earlier transplutonium actinides, with a decrease in stability constants with aminopolycarboxylate ligands. This report studies transplutonium chemistry - including Am, Bk, Cf, and Es - with aminopolycarboxylate ligands. Es complexation follows similar thermodynamic and structural trends established by the earlier actinides, consistent with first-principle calculations.
- Published
- 2018
39. Quantitative Evidence for Lanthanide-Oxygen Orbital Mixing in CeO2, PrO2, and TbO2
- Author
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Enrique R. Batista, S. Chantal E. Stieber, David Clark, Richard L. Martin, Stefan G. Minasian, Stosh A. Kozimor, Jason M. Keith, David K. Shuh, Xiaodong Wen, Wayne W. Lukens, Corwin H. Booth, and Tolek Tylisczcak
- Subjects
Lanthanide ,X-ray absorption spectroscopy ,Absorption spectroscopy ,Chemistry ,Ionic bonding ,02 engineering and technology ,General Chemistry ,Electronic structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,Catalysis ,0104 chemical sciences ,Colloid and Surface Chemistry ,Atomic orbital ,Covalent bond ,Physical chemistry ,Density functional theory ,0210 nano-technology - Abstract
© 2017 American Chemical Society. Understanding the nature of covalent (band-like) vs ionic (atomic-like) electrons in metal oxides continues to be at the forefront of research in the physical sciences. In particular, the development of a coherent and quantitative model of bonding and electronic structure for the lanthanide dioxides, LnO2(Ln = Ce, Pr, and Tb), has remained a considerable challenge for both experiment and theory. Herein, relative changes in mixing between the O 2p orbitals and the Ln 4f and 5d orbitals in LnO2are evaluated quantitatively using O K-edge X-ray absorption spectroscopy (XAS) obtained with a scanning transmission X-ray microscope and density functional theory (DFT) calculations. For each LnO2, the results reveal significant amounts of Ln 5d and O 2p mixing in the orbitals of t2g(σ-bonding) and eg(π-bonding) symmetry. The remarkable agreement between experiment and theory also shows that significant mixing with the O 2p orbitals occurs in a band derived from the 4f orbitals of a2usymmetry (σ-bonding) for each compound. However, a large increase in orbital mixing is observed for PrO2that is ascribed to a unique interaction derived from the 4f orbitals of t1usymmetry (σ- and π-bonding). O K-edge XAS and DFT results are compared with complementary L3-edge and M5,4-edge XAS measurements and configuration interaction calculations, which shows that each spectroscopic approach provides evidence for ground state O 2p and Ln 4f orbital mixing despite inducing very different core-hole potentials in the final state.
- Published
- 2017
40. Assessment of Tuned Range Separated Exchange Functionals for Spectroscopies and Properties of Uranium Complexes
- Author
-
Ping Yang, Jochen Autschbach, Thomas J. Duignan, and Enrique R. Batista
- Subjects
Valence (chemistry) ,010304 chemical physics ,Excitation spectra ,Analytical chemistry ,chemistry.chemical_element ,Uranium ,010402 general chemistry ,01 natural sciences ,Molecular physics ,0104 chemical sciences ,Computer Science Applications ,Delocalized electron ,chemistry ,0103 physical sciences ,Physics::Atomic and Molecular Clusters ,Physical and Theoretical Chemistry ,Open shell - Abstract
The Kohn–Sham delocalization error (DE) is quantified in select uranium compounds for various functionals and shown to correlate with the magnitude of dative ligand donation into the 5f shell. Range separated exchange functionals are reparametrized to minimize the DE and analyzed for their spectroscopic predictive capabilities. Valence excitation spectra of occupied 5f systems exhibit noticeable improvement upon reparametrization, e.g. UCl6–, UCl62–, and UO2+. Less sensitivity to the reparameterization was observed for closed shell 5f systems and core excitation spectra. A general parametrization is proposed to perform well for valence excitation spectra with small DE.
- Published
- 2017
41. Covalency in Americium(III) Hexachloride
- Author
-
Stosh A. Kozimor, Justin N. Cross, Brian L. Scott, Samantha K. Cary, Ping Yang, Enrique R. Batista, Cory J. Windorff, Benjamin W. Stein, William J. Evans, Jing Su, and Veronika Mocko
- Subjects
X-ray absorption spectroscopy ,Americium ,Absorption spectroscopy ,010405 organic chemistry ,Chemistry ,Extramural ,chemistry.chemical_element ,General Chemistry ,Electronic structure ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Catalysis ,0104 chemical sciences ,Colloid and Surface Chemistry ,Chlorides ,Chemical physics ,Computational chemistry ,Mixing (physics) - Abstract
Developing a better understanding of covalency (or orbital mixing) is of fundamental importance. Covalency occupies a central role in directing chemical and physical properties for almost any given compound or material. Hence, the concept of covalency has potential to generate broad and substantial scientific advances, ranging from biological applications to condensed matter physics. Given the importance of orbital mixing combined with the difficultly in measuring covalency, estimating or inferring covalency often leads to fiery debate. Consider the 60-year controversy sparked by Seaborg and co-workers ( Diamond, R. M.; Street, K., Jr.; Seaborg, G. T. J. Am. Chem. Soc. 1954 , 76 , 1461 ) when it was proposed that covalency from 5f-orbitals contributed to the unique behavior of americium in chloride matrixes. Herein, we describe the use of ligand K-edge X-ray absorption spectroscopy (XAS) and electronic structure calculations to quantify the extent of covalent bonding in-arguably-one of the most difficult systems to study, the Am-Cl interaction within AmCl
- Published
- 2017
42. Degradation of Alkali-Based Photocathodes from Exposure to Residual Gases: A First-Principles Study
- Author
-
Ravindra Pandey, Nathan A. Moody, Enrique R. Batista, and Gaoxue Wang
- Subjects
Chemistry ,Ultra-high vacuum ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Alkali metal ,01 natural sciences ,Photocathode ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,General Energy ,Caesium ,0103 physical sciences ,Antimonide ,Reactivity (chemistry) ,Quantum efficiency ,Density functional theory ,Physical and Theoretical Chemistry ,010306 general physics ,0210 nano-technology - Abstract
Photocathodes are a key component in the production of electron beams in systems such as X-ray free-electron lasers and X-ray energy-recovery linacs. Alkali-based materials display high quantum efficiency (QE), however, their QE undergoes degradation faster than metal photocathodes even in the high vacuum conditions where they operate. The high reactivity of alkali-based surfaces points to surface reactions with residual gases as one of the most important factors for the degradation of QE. To advance the understanding on the degradation of the QE, we investigated the surface reactivity of common residual gas molecules (e.g., O2, CO2, CO, H2O, N2, and H2) on one of the best-known alkali-based photocathode materials, cesium antimonide (Cs3Sb), using first-principles calculations based on density functional theory. The reaction sites, adsorption energy, and effect in the local electronic structure upon reaction of these molecules on (001), (110), and (111) surfaces of Cs3Sb were computed and analyzed. The ad...
- Published
- 2017
43. Synthesis and Characterization of the Actinium Aquo Ion
- Author
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Kevin D. John, Maryline G. Ferrier, John M. Berg, Lindsay N. Redman, Benjamin W. Stein, Juan S. Lezama Pacheco, Eva R. Birnbaum, Stosh A. Kozimor, Jonathan W. Engle, and Enrique R. Batista
- Subjects
chemistry.chemical_classification ,010405 organic chemistry ,Chemistry ,General Chemical Engineering ,Inorganic chemistry ,chemistry.chemical_element ,General Chemistry ,010402 general chemistry ,01 natural sciences ,3. Good health ,0104 chemical sciences ,Characterization (materials science) ,Coordination complex ,Ion ,Metal ,lcsh:Chemistry ,Actinium ,lcsh:QD1-999 ,visual_art ,visual_art.visual_art_medium ,Molecule ,Absorption (chemistry) ,Metal aquo complex ,Research Article - Abstract
Metal aquo ions occupy central roles in all equilibria that define metal complexation in natural environments. These complexes are used to establish thermodynamic metrics (i.e., stability constants) for predicting metal binding, which are essential for defining critical parameters associated with aqueous speciation, metal chelation, in vivo transport, and so on. As such, establishing the fundamental chemistry of the actinium(III) aquo ion (Ac-aquo ion, Ac(H2O)x3+) is critical for current efforts to develop 225Ac [t1/2 = 10.0(1) d] as a targeted anticancer therapeutic agent. However, given the limited amount of actinium available for study and its high radioactivity, many aspects of actinium chemistry remain poorly defined. We overcame these challenges using the longer-lived 227Ac [t1/2 = 21.772(3) y] isotope and report the first characterization of this fundamentally important Ac-aquo coordination complex. Our X-ray absorption fine structure study revealed 10.9 ± 0.5 water molecules directly coordinated to the AcIII cation with an Ac–OH2O distance of 2.63(1) Å. This experimentally determined distance was consistent with molecular dynamics density functional theory results that showed (over the course of 8 ps) that AcIII was coordinated by 9 water molecules with Ac–OH2O distances ranging from 2.61 to 2.76 Å. The data is presented in the context of other actinide(III) and lanthanide(III) aquo ions characterized by XAFS and highlights the uniqueness of the large AcIII coordination numbers and long Ac–OH2O bond distances., The actinium aquo complex has been characterized using Ac L3-edge X-ray absorption spectroscopy and molecular dynamics density functional theory.
- Published
- 2017
44. Evaluating the electronic structure of formal LnIIions in LnII(C5H4SiMe3)31−using XANES spectroscopy and DFT calculations
- Author
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Juan S. Lezama Pacheco, Gregory L. Wagner, Enrique R. Batista, David H. Woen, Jing Su, Austin J. Ryan, Maryline G. Ferrier, Stosh A. Kozimor, Samantha K. Cary, Jonathan W. Engle, Tonya Vitova, Benjamin W. Stein, Ping Yang, Angela C. Olson, William J. Evans, and Megan E. Fieser
- Subjects
Lanthanide ,010405 organic chemistry ,Chemistry ,Transition dipole moment ,General Chemistry ,Electronic structure ,010402 general chemistry ,01 natural sciences ,XANES ,0104 chemical sciences ,Ion ,Computational chemistry ,Physical chemistry ,Density functional theory ,Electron configuration ,Spectroscopy - Abstract
The isolation of [K(2.2.2-cryptand)][Ln(C5H4SiMe3)3], formally containing LnII, for all lanthanides (excluding Pm) was surprising given that +2 oxidation states are typically regarded as inaccessible for most 4f-elements. Herein, X-ray absorption near-edge spectroscopy (XANES), ground-state density functional theory (DFT), and transition dipole moment calculations are used to investigate the possibility that Ln(C5H4SiMe3)31- (Ln = Pr, Nd, Sm, Gd, Tb, Dy, Y, Ho, Er, Tm, Yb and Lu) compounds represented molecular LnII complexes. Results from the ground-state DFT calculations were supported by additional calculations that utilized complete-active-space multi-configuration approach with second-order perturbation theoretical correction (CASPT2). Through comparisons with standards, Ln(C5H4SiMe3)31- (Ln = Sm, Tm, Yb, Lu, Y) are determined to contain 4f6 5d0 (SmII), 4f13 5d0 (TmII), 4f14 5d0 (YbII), 4f14 5d1 (LuII), and 4d1 (YII) electronic configurations. Additionally, our results suggest that Ln(C5H4SiMe3)31- (Ln = Pr, Nd, Gd, Tb, Dy, Ho, and Er) also contain LnII ions, but with 4f n 5d1 configurations (not 4f n+1 5d0). In these 4f n 5d1 complexes, the C3h-symmetric ligand environment provides a highly shielded 5d-orbital of a' symmetry that made the 4f n 5d1 electronic configurations lower in energy than the more typical 4f n+1 5d0 configuration.
- Published
- 2017
45. Dimension and bridging ligand effects on Mo-mediated catalytic transformation of dinitrogen to ammonia: Chain-like extended models of Nishibayashi’s catalyst
- Author
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Xiao Lan Sheng, Enrique R. Batista, Yong Hui Tian, and Yi Xiang Duan
- Subjects
010405 organic chemistry ,Inorganic chemistry ,chemistry.chemical_element ,Bridging ligand ,010402 general chemistry ,Condensed Matter Physics ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Carbide ,Catalysis ,Metal ,Crystallography ,Ammonia ,chemistry.chemical_compound ,chemistry ,Catalytic cycle ,Molybdenum ,visual_art ,visual_art.visual_art_medium ,Physical and Theoretical Chemistry ,Bimetallic strip - Abstract
Previous studies suggested that in Nishibayashi’s homogenous catalytic systems based on molybdenum (Mo) complexes, the bimetallic structure facilitated dinitrogen to ammonia conversion in comparison to the corresponding monometallic complexes, likely due to the through-bond interactions between the two Mo centers. However, more detailed model systems are necessary to support this bimetallic hypothesis, and to elucidate the multi-metallic effects on the catalytic mechanism. In this work, we computationally examined the effects of dimension as well as the types of bridging ligands on the catalytic activities of molybdenum-dinitrogen complexes by using a set of extended model systems based on Nishibayashi’s bimetallic structure. The polynuclear chains containing four ([Mo]4) or more Mo centers were found to drastically enhance the catalytic performance by comparing with both the monometallic and bimetallic complexes. Carbide ([:C C:]2−) was found to be a more effective bridging ligand than N2 in terms of electronic charges dispersion between metal centers thereby facilitating reactions in the catalytic cycle. The mechanistic modelling suggests that in principle, more efficient catalytic system for N2 to NH3 transformation might be obtained by extending the polynuclear chain to a proper size in combination with an effective bridging ligand for charge dispersion.
- Published
- 2016
46. Design, Isolation, and Spectroscopic Analysis of a Tetravalent Terbium Complex
- Author
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Natalie T. Rice, John Bacsa, Joshua Telser, Enrique R. Batista, Dominic R. Russo, Ping Yang, Henry S. La Pierre, and Ivan A. Popov
- Subjects
Models, Molecular ,Lanthanide ,Ligand field theory ,Phosphoranes ,chemistry.chemical_element ,Terbium ,Ligands ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Catalysis ,law.invention ,Colloid and Surface Chemistry ,Coordination Complexes ,law ,Electron paramagnetic resonance ,X-ray absorption spectroscopy ,Ligand ,Electron Spin Resonance Spectroscopy ,General Chemistry ,Combinatorial chemistry ,0104 chemical sciences ,Characterization (materials science) ,Crystallography ,X-Ray Absorption Spectroscopy ,chemistry ,Covalent bond ,Yield (chemistry) ,Density functional theory - Abstract
Synthetic strategies to yield molecular complexes of high-valent lanthanides, other than the ubiquitous Ce4+ ion, are exceptionally rare, and thorough, detailed characterization in these systems is limited by complex lifetime and reaction and isolation conditions. The synthesis of high-symmetry complexes in high purity with significant lifetimes in solution and solid-state are essential for determining the role of ligand-field splitting, multiconfigurational behavior, and covalency in governing the reactivity and physical properties of these potentially technologically transformative tetravalent ions. We report the synthesis and physical characterization of an S4 symmetric, four-coordinate tetravalent terbium complex, [Tb(NP(1,2-bis-tBu-diamidoethane)(NEt2))4] (where Et is ethyl and tBu is tert-butyl). The ligand field in this complex is weak and the metal-ligand bonds sufficiently covalent so that the tetravalent terbium ion is stable and accessible via a mild oxidant from the anionic, trivalent, terbium precursor, [(Et2O)K][Tb(NP(1,2-bis-tBu-diamidoethane)(NEt2))4]. The significant stability of the tetravalent complex enables its thorough characterization. The step-wise development of the supporting ligand points to key ligand control elements for further extending the known tetravalent lanthanide ions in molecular complexes. Magnetic susceptibility, electron paramagnetic resonance (EPR) spectroscopy, X-ray absorption near-edge spectroscopy (XAS), and density functional theory studies indicate a 4f7 ground state for [Tb(NP(1,2-bis-tBu-diamidoethane)(NEt2))4] with considerable zero-field splitting: demonstrating that magnetic, tetravalent lanthanide ions engage in covalent metal-ligand bonds. This result has significant implications for the use of tetravalent lanthanide ions in magnetic applications since the observed zero-field splitting is intermediate between that observed for the trivalent lanthanides and for the transition metals. The similarity of the multiconfigurational behavior in the ground state of [Tb(NP(1,2-bis-tBu-diamidoethane)(NEt2))4] (measured by Tb L3-edge XAS) to that observed in TbO2 implicates ligand control of multiconfigurational behavior as a key component of the stability of the complex.
- Published
- 2019
47. Homoleptic Imidophosphorane Stabilization of Tetravalent Cerium
- Author
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Thaige P. Gompa, Enrique R. Batista, Dominic R. Russo, Lukáš Palatinus, Natalie T. Rice, Henry S. La Pierre, Joshua Telser, John Bacsa, Jing Su, and Ping Yang
- Subjects
Coordination sphere ,Absorption spectroscopy ,010405 organic chemistry ,Chemistry ,Ligand ,chemistry.chemical_element ,010402 general chemistry ,01 natural sciences ,Redox ,0104 chemical sciences ,law.invention ,Inorganic Chemistry ,Crystallography ,chemistry.chemical_compound ,Cerium ,law ,Density functional theory ,Physical and Theoretical Chemistry ,Homoleptic ,Electron paramagnetic resonance - Abstract
The homoleptic complexes of cerium with the tris(piperidinyl)imidophosphorane ligand, [NP(pip)3]-, present the most negative Ce3+/4+ redox couple known ( 4.0 V shift from the Ce3+/4+ couple in 1 M HClO4(aq)] is established through reactivity studies. Spectroscopic studies (UV-vis, electron paramagnetic resonance, and Ce L3-edge X-ray absorption spectroscopy), in conjunction with density functional theory studies, reveal the dominant covalent metal-ligand interactions underlying the observed redox chemistry and the dependence of the redox potential on the binding of potassium in the inner coordination sphere.
- Published
- 2019
48. AnO2-Cl Coordination Chemistry at High P/T
- Author
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Hakim Boukhalfa, Morgan P. Kelley, Jing Su, Xiaobin Zhang, Ping Yang, Hongwu Xu, Jason Baker, Enrique R. Batista, and Artaches Migdissov
- Subjects
chemistry.chemical_classification ,Chemistry ,Medicinal chemistry ,Coordination complex - Published
- 2019
49. Energy-Degeneracy-Driven Covalency in Actinide Bonding
- Author
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Andrew Kerridge, Steven D. Conradson, Sharon E. Bone, Alex S. Ditter, Samantha K. Cary, Marianne P. Wilkerson, Enrique R. Batista, Richard L. Martin, Stefan G. Minasian, Stosh A. Kozimor, Henry S. La Pierre, Nikolas Kaltsoyannis, Kevin S. Boland, Matthias W. Löble, Veronika Mocko, Jason M. Keith, Laura E. Wolfsberg, David K. Shuh, David Clark, J. A. Bradley, Jing Su, Gerald T. Seidler, and Ping Yang
- Subjects
Chemical substance ,Absorption spectroscopy ,010405 organic chemistry ,Chemistry ,Actinide ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Catalysis ,0104 chemical sciences ,Metal ,ResearchInstitutes_Networks_Beacons/dalton_nuclear_institute ,Colloid and Surface Chemistry ,Chemical bond ,Covalent bond ,visual_art ,Chemical Sciences ,visual_art.visual_art_medium ,Physical chemistry ,Dalton Nuclear Institute ,Density functional theory ,Degeneracy (biology) - Abstract
Evaluating the nature of chemical bonding for actinide elements represents one of the most important and long-standing problems in actinide science. We directly address this challenge and contribute a Cl K-edge X-ray absorption spectroscopy and relativistic density functional theory study that quantitatively evaluates An-Cl covalency in AnCl62- (AnIV = Th, U, Np, Pu). The results showed significant mixing between Cl 3p- and AnIV 5f- and 6d-orbitals (t1u*/t2u* and t2 g*/eg *), with the 6d-orbitals showing more pronounced covalent bonding than the 5f-orbitals. Moving from Th to U, Np, and Pu markedly changed the amount of M-Cl orbital mixing, such that AnIV 6d - and Cl 3p-mixing decreased and metal 5f - and Cl 3p-orbital mixing increased across this series.
- Published
- 2018
50. Plutonium coordination and redox chemistry with the CyMe4-BTPhen polydentate N-donor extractant ligand
- Author
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Frank W. Lewis, Daniel M Whittaker, Clint A. Sharrad, Jason M. Keith, Andrew J. Gaunt, Ping Yang, Laurence M. Harwood, Sean D. Reilly, Enrique R. Batista, Brian L. Scott, Jing Su, and Michael J. Hudson
- Subjects
Denticity ,Inorganic chemistry ,F100 ,chemistry.chemical_element ,010402 general chemistry ,01 natural sciences ,Redox ,Catalysis ,Metal ,chemistry.chemical_compound ,Materials Chemistry ,Acetonitrile ,Spectroscopy ,010405 organic chemistry ,Ligand ,Metals and Alloys ,General Chemistry ,Actinide ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Plutonium ,chemistry ,visual_art ,Ceramics and Composites ,visual_art.visual_art_medium - Abstract
Complexation of Pu(IV) with the actinide extractant CyMe4-BTPhen (2,9-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-1,2,4-benzotriazin-3-yl)-1,10-phenanthroline) was followed by UV/vis spectroscopy in acetonitrile solution. The solid-state structure of the crystallized product suggests that Pu(IV) is reduced to Pu(III) upon complexation. Analysis by DFT modeling is consistent with metal-based rather than ligand-based reduction.
- Published
- 2018
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