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4 results on '"U.S. Department of Energy"'

1. Domain Wall Dynamics in a Ferroelastic Spin Crossover Complex with Giant Magnetoelectric Coupling

Author

Vibe Boel Jakobsen, Elzbieta Trzop, Emiel Dobbelaar, Laurence C. Gavin, Shalinee Chikara, Xiaxin Ding, Minseong Lee, Kane Esien, Helge Müller-Bunz, Solveig Felton, Eric Collet, Michael A. Carpenter, Vivien S. Zapf, Grace G. Morgan, University College Dublin [Dublin] (UCD), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Auburn University (AU), Los Alamos National Laboratory (LANL), Queen's University [Belfast] (QUB), University of Cambridge [UK] (CAM), Science Foundation Ireland (SFI) Science Foundation Ireland [19/FFP/6909], Irish Research CouncilIrish Research Council for Science, Engineering and Technology [GOIPG/2016/73], Augustinus Fonden [18-0338], Oticon Fonden [17-3813], Reinholdt W. Jorck og Hustrus Fond [18-JI-0573], P. A. Fiskers Fond, A. P. MOller og Hustru Chastine Mc-Kinney MOllers Fond til almene Formaal, Christian og Ottilia Brorsons Rejselegat for yngre videnskabsmaend og-kvinder, Natural Environment Research Council of Great Britain [NE/B505738/1, NE/F17081/1], Engineering and Physical Sciences Research CouncilUK Research and Innovation (UKRI) Engineering and Physical Sciences Research Council (EPSRC) [EP/I036079/1], U.S. National Science FoundationNational Science Foundation (NSF) [DMR-1157490], State of Florida, U.S. Department of Energy United States Department of Energy (DOE), Laboratory-Directed Research and Development program (LDRD), U.S. Department of Energy, Office of Science, Basic Energy Sciences United States Department of Energy (DOE) [DE SC0019330], Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Colloid and Surface Chemistry, Phase transitions, Polarization, Order, General Chemistry, Transition metals, Biochemistry, Quantum mechanics, Catalysis, Article
Abstract

International audience; Pinned and mobile ferroelastic domain walls are detected in response to mechanical stress in a Mn3+ complex with two-step thermal switching between the spin triplet and spin quintet forms. Single-crystal X-ray diffraction and resonant ultrasound spectroscopy on [Mn-III(3,5-diCl-sal(2)(323))]BPh4 reveal three distinct symmetry-breaking phase transitions in the polar space group series Cc -> Pc -> P1 -> P1((1/2)). The transition mechanisms involve coupling between structural and spin state order parameters, and the three transitions are Landau tricritical, first order, and first order, respectively. The two first-order phase transitions also show changes in magnetic properties and spin state ordering in the Jahn-Teller-active Mn3+ complex. On the basis of the change in symmetry from that of the parent structure, Cc, the triclinic phases are also ferroelastic, which has been confirmed by resonant ultrasound spectroscopy. Measurements of magnetoelectric coupling revealed significant changes in electric polarization at both the Pc -> P1 and P1 -> P1((1/2)) transitions, with opposite signs. All these phases are polar, while P1 is also chiral. Remanent electric polarization was detected when applying a pulsed magnetic field of 60 T in the P1 -> P1((1/2)) region of bistability at 90 K. Thus, we showcase here a rare example of multifunctionality in a spin crossover material where the strain and polarization tensors and structural and spin state order parameters are strongly coupled.

Published
2021

2. The Nature of Secondary Interactions at Electrophilic Metal Sites of Molecular and Silica-Supported Organolutetium Complexes from Solid-State NMR Spectroscopy

Author

Richard A. Andersen, Laurent Maron, Christophe Copéret, Anne Lesage, Wayne W. Lukens, Kevin J. Sanders, David Gajan, Iker del Rosal, Matthew P. Conley, Giuseppe Lapadula, Department of Chemistry and Applied Biosciences [ETH Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Biological Solid-State NMR Methods - Méthodes de RMN à l'état solide en biologie, Institut des Sciences Analytiques (ISA), Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Solid-State NMR Methods for Materials - Méthodes de RMN à l'état solide pour les matériaux, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, C.C. thanks the Miller Institute for a Visiting Professor position at UC Berkeley, during which this manuscript was finalized. Portions of this work were performed at Lawrence Berkeley National Laboratory under contract no. DE-AC02-05CH11231 and at the Stanford Synchrotron Radiation Lightsource (SSRL). Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under contract no. DE-AC02-76SF00515. Portions of this work were supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Chemical Sciences, Biosciences, and Geosciences Division (CSGB), Heavy Element Chemistry Program and were performed at Lawrence Berkeley National Laboratory under contract no. DE-AC02-05CH11231. We also thank the HPCs CALcul en Midi-Pyrennes (CALIMP-EOS, grant P0833) for the generous allocation of computer time. Financial support from the TGIR-RMN-THC Fr3050 CNRS for conducting the research is gratefully acknowledged., Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), University of California [Berkeley] (UC Berkeley), and University of California (UC)-University of California (UC)

Subjects
010405 organic chemistry, Chemistry, Resonance, Nanotechnology, General Chemistry, Nuclear magnetic resonance spectroscopy, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, Spectral line, 0104 chemical sciences, Crystallography, Colloid and Surface Chemistry, Solid-state nuclear magnetic resonance, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Chemical Sciences, Electrophile, Proton NMR, [CHIM]Chemical Sciences, Spectroscopy, Natural bond orbital
Abstract

International audience; Lu[CH(SiMe3)2]3 reacts with [SiO2-700] to give [(≡SiO)Lu[CH(SiMe3)2]2] and CH2(SiMe3)2. [(≡SiO)Lu[CH(SiMe3)2]2] is characterized by solid-state NMR and EXAFS spectroscopy, which show that secondary Lu···C and Lu···O interactions, involving a γ-CH3 and a siloxane bridge, are present. From X-ray crystallographic analysis, the molecular analogues Lu[CH(SiMe3)2]3-x[O-2,6-tBu-C6H3]x (x = 0-2) also have secondary Lu···C interactions. The (1)H NMR spectrum of Lu[CH(SiMe3)2]3 shows that the -SiMe3 groups are equivalent to -125 °C and inequivalent below that temperature, ΔG(⧧)(Tc = 148 K) = 7.1 kcal mol(-1). Both -SiMe3 groups in Lu[CH(SiMe3)2]3 have (1)JCH = 117 ± 1 Hz at -140 °C. The solid-state (13)C CPMAS NMR spectrum at 20 °C shows three chemically inequivalent resonances in the area ratio of 4:1:1 (12:3:3); the J-resolved spectra for each resonance give (1)JCH = 117 ± 2 Hz. The (29)Si CPMAS NMR spectrum shows two chemically inequivalent resonances with different values of chemical shift anisotropy. Similar observations are obtained for Lu[CH(SiMe3)2]3-x[O-2,6-tBu-C6H3]x (x = 1 and 2). The spectroscopic data point to short Lu···Cγ contacts corresponding to 3c-2e Lu···Cγ-Siβ interactions, which are supported by DFT calculations. Calculated natural bond orbital (NBO) charges show that Cγ carries a negative charge, while Lu, Hγ, and Siβ carry positive charges; as the number of O-based ligands increases so does the positive charge at Lu, which in turns shortens the Lu···Cγ distance. The change in NBO charges and the resulting changes in the spectroscopic and crystallographic properties show how ligands and surface-support sites rearrange to accommodate these changes, consistent with Pauling's electroneutrality concept.

Published
2016

3. Organic Cation Alloying on Intralayer A and Interlayer A’ sites in 2D Hybrid Dion–Jacobson Lead Bromide Perovskites (A’)(A)Pb2Br7

Author

Constantinos C. Stoumpos, Peijun Guo, Ioannis Spanopoulos, Mercouri G. Kanatzidis, Claudine Katan, Richard D. Schaller, Mikaël Kepenekian, Lingling Mao, Yihui He, Jacky Even, Ram Seshadri, Northwestern University [Evanston], Argonne National Laboratory [Lemont] (ANL), Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Institut des Fonctions Optiques pour les Technologies de l'informatiON (Institut FOTON), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), University of California [Santa Barbara] (UCSB), University of California, University of Crete [Heraklion] (UOC), SC0012541, Basic Energy Sciences, DE-AC02-06CH11357, U.S. Department of Energy, Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS), University of California [Santa Barbara] (UC Santa Barbara), and University of California (UC)

Subjects
[PHYS]Physics [physics], Photoluminescence, Band gap, Chemistry, Halide, General Chemistry, Crystal structure, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, 0104 chemical sciences, symbols.namesake, Crystallography, Colloid and Surface Chemistry, Formamidinium, Lattice (order), symbols, [CHIM]Chemical Sciences, Density functional theory, Raman spectroscopy
Abstract

International audience; Hybrid layered halide perovskites have achieved impressive performance in optoelectronics. New structural types in the two-dimensional (2D) halide system such as the Dion-Jacobson phases have attracted wide research attention due to the short interlayer distance and unique layer orientation that facilitate better charge-transport and higher stability in optoelectronic devices. Here, we report the first solid solution series incorporating both A and A’ cations in the 2D Jacobson-Dion family, with the general formula (A’)(A)Pb2Br7 ((A’ = 3-(aminomethyl)piperidinium (3AMP) and 4-(aminomethyl)piperidinium) (4AMP); A= methylammonium (MA) and formamidinium (FA)). Mixing the spacing A’ cations and perovskitizer A cations generates the new (3AMP)a(4AMP)1-a(FA)b(MA)1-bPb2Br7 perovskites. The crystallographically refined crystal structures using single-crystal X-ray diffraction data re-veal that the distortion of the inorganic framework is heavily influenced by the degree of A’ and A alloying. A rising fraction of 4AMP in the structure, decreases the Pb-Br-Pb angles, making the framework more distorted. On the contrary, higher FA fractions increase the Pb-Br-Pb angles. This structural evolution fine tunes the optical properties where the larger the Pb-Br-Pb angle, the narrower the band gap. The photoluminescence emission energy mirrors this trend. Raman spectroscopy reveals a highly dynamical lattice similar to MAPbBr3 and consistent with the local distortion environment of the [Pb2Br7] framework. Density Functional Theory (DFT) calculations of the electronic structures reveal the same trend as the experimental results where (3AMP)(FA)Pb2Br7 has the smallest band gap while (4AMP)(MA)Pb2Br7 has the largest band gap. The structural effects from solely the organic cati-ons in the 2D system highlight the importance of understanding the high sensitivity of the optoelectronic properties on the struc-tural tuning in this broad class of materials.

Published
2020

4. One-step synthesis of core(Cr)/shell(gamma-Fe2O3) nanoparticles

Author

Thomas Vogt, Claude Estournès, Katja Loos, Kurikka V.P.M. Shafi, Yongjae Lee, Ronit Popovitz-Biro, Abraham Ulman, Jriuan Lai, Centre National de la Recherche Scientifique - CNRS (FRANCE), Polytechnic Institute of New York University (USA), Université de Strasbourg - UNISTRA (FRANCE), University of Groningen (NETHERLANDS), Weizmann Institute of Science (ISRAEL), Brookhaven National Laboratory - BNL (USA), Institut de Physique et Chimie des Matériaux de Strasbourg - IPCMS (Strasbourg, France), Polytechnic Institute of New York University, University of Groningen [Groningen], Weizmann Institute of Science [Rehovot, Israël], Brookhaven National Laboratory [Upton, NY] (BNL), U.S. Department of Energy [Washington] (DOE)-UT-Battelle, LLC-Stony Brook University [SUNY] (SBU), State University of New York (SUNY)-State University of New York (SUNY), Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Faculty of Science and Engineering, Macromolecular Chemistry & New Polymeric Materials, Polymers at Surfaces and Interfaces, and Zernike Institute for Advanced Materials

Subjects
Nanostructure, Shell (structure), Analytical chemistry, Iron oxide, Nanoparticle, 02 engineering and technology, Crystal structure, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, chemistry.chemical_compound, [CHIM.GENI]Chemical Sciences/Chemical engineering, Colloid and Surface Chemistry, Nuclear magnetic resonance, Génie chimique, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, Génie des procédés, GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries), OXIDE NANOPARTICLES, Chemistry, SUPERLATTICES, General Chemistry, 021001 nanoscience & nanotechnology, COLLOIDS, 0104 chemical sciences, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, Magnetic nanoparticles, CORE-SHELL NANOPARTICLES, 0210 nano-technology, CLUSTERS, Stoichiometry, IRON PARTICLES, Superparamagnetism
Abstract

Core(Cr)/shell(gamma-Fe(2)O(3)) nanoparticles were synthesized by mixing Fe(CO)(5) and Cr(CO)(6) in the 9:1 ratio. These particles exhibit narrow size distribution with 13.5 nm as mean diameter and uniform spherical shape. The TEM image, which is in good agreement with the synchrotron powder XRD pattern, reveals the heterogeneous nature (core/shell structure). The analysis of the pattern reveals gamma-Fe(2)O(3) structure and a metal crystal structure. Mossbauer spectra, which support the superparamagnetic behavior determined by H-M measurement, do not show any traceable amount of Fe(0). This suggests that the metal component is Cr. EELS analysis and iron mapping suggest controlled stoichiometry and also confirm a core made of Cr and a shell made of gamma-Fe(2)O(3).

Published
2005

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