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At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Physical properties of metallic antiferromagneticCaCo1.86As2 single crystals

X-ray powder diffraction (XRD), magnetic susceptibility χ, isothermal magnetization M, heat capacity Cp, and in-plane electrical resistivity ρ measurements as a function of temperature T and magnetic field H are presented for CaCo1.86As2 single crystals. The electronic structure is probed by angle-resolved photoemission spectroscopy (ARPES) measurements of CaCo1.86As2 and by full-potential linearized augmented-plane-wave calculations for the supercell Ca8Co15As16 (CaCo1.88As2). Our XRD crystal structure refinement is consistent with the previous combined refinement of x-ray and neutron powder diffraction data showing a collapsed-tetragonal ThCr2Si2-type structure with 7(1)% vacancies on the Co sites corresponding to the composition CaCo1.86As2 [D. G. Quirinale et al., Phys. Rev. B 88, 174420 (2013)]. The anisotropic χ(T) data are consistent with the magnetic neutron diffraction data of Quirianale et al. that demonstrate the presence of A-type collinear antiferromagnetic order below the Néel temperature TN=52(1) K with the easy axis being the tetragonal c axis. However, no clear evidence from the ρ(T) and Cp(T) data for a magnetic transition at TN is observed. A metallic ground state is demonstrated from the band calculations and the ρ(T), Cp(T), and ARPES data, and spin-polarized calculations indicate a competition between the A-type AFM and FM ground states. The Cp(T) data exhibit a large Sommerfield electronic coefficient reflecting a large density of states at the Fermi energy D(EF) that is enhanced compared with the band structure calculation where the bare D(EF) arises from Co 3d bands. At 1.8 K, the M(H) data for H∥c exhibit a well-defined first-order spin-flop transition at an applied field of 3.5 T. The small ordered moment of ≈0.3μB/Co obtained from the M(H) data at low T, the large exchange enhancement of χ and the lack of a self-consistent interpretation of the χ(T) and M(H,T) data in terms of a local moment Heisenberg model together indicate that the magnetism of CaCo1.86As2 is itinerant.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Crystal structure of mupirocin form I, C26H44O9

The crystal structure of mupirocin Form I has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Mupirocin Form I crystallizes in space group P 2 1 (#4) with a = 12.562 81(16), b = 5.103 63(4), c = 21.713 34(29) Å, β = 100.932(1)°, V = 1366.91(2) Å 3 , and Z = 2. Although the three hydroxyl groups and the carboxylic acid participate in a three-dimensional hydrogen bond network, the crystal energy appears to be dominated by van der Waals interactions. The Rietveld-refined and density functional optimized structures differ significantly. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File ™ .

Kaduk, James A.↗
DOE OSTI2017

Crystal structure of paliperidone palmitate (INVEGA SUSTENNA®), C39H57FN4O4

The crystal structure of paliperidone palmitate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Paliperidone palmitate crystallizes in space group P 2 1 / c (#14) with a = 34.415 40(35), b = 10.093 49(7), c = 10.904 92(9) Å, β = 94.3917(9)°, V = 3776.94(6) Å 3 , and Z = 4. The conformation of the paliperidone fragment differs from that of the parent compound. The palmitate chain exhibits a slight twist close to the ester group. Several C–H•••O hydrogen bonds contribute to the crystal packing, which is dominated by van der Waals interactions. The powder pattern is included in the Powder Diffraction File™ as entry 00-066-1614.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Collinear antiferromagnetic order in a quasi-two-dimensional triangular lattice compound DyNiAl 4 Ge 2

The two-dimensional magnetic triangular lattice, with rare-earth local moments coupled through long-range interactions and hosting strong spin-orbit coupling, serves as an ideal platform for exploring novel quantum phenomena. Here, we report the physical properties of DyNiAl 4 Ge 2 single crystals through comprehensive structural, magnetic, heat capacity, electrical transport, and neutron powder diffraction measurements. DyNiAl 4 Ge 2 crystallizes in a trigonal lattice with the space group $R\bar{3}m$, where Dy atoms form two-dimensional triangular lattice layers within the 𝑎𝑏 plane and stack along the 𝑐 axis. Magnetic susceptibility measurement reveals a magnetic phase transition at 𝑇 𝑁 = 9.0 K, further confirmed by the 𝜆-shaped peak in the heat capacity curve. The obtained temperature-magnetic field phase diagram is relatively simple compared to other isostructural compounds, suggesting the absence of magnetic frustration. This is further evidenced by neutron powder diffraction, which shows a collinear antiferromagnetic ground state with a propagation vector 𝒌 = (0, 0, 1.5), implying the absence of magnetic frustration in DyNiAl 4 Ge 2 . In this magnetic structure, Dy moments are aligned ferromagnetically within each triangular layer and arranged antiferromagnetically between adjacent layers along the 𝑐 axis. In conclusion, our results establish DyNiAl 4 Ge 2 as a model system for understanding the interplay between RKKY interaction and geometrical frustration in this family of compounds.

Wu, HengHeng [Chinese Academy of Sciences (CAS), S↗
DOE OSTI2024

Crystal structure of alectinib hydrochloride Type I, C 30 H 35 N 4 O 2 Cl

The crystal structure of alectinib hydrochloride has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Alectinib hydrochloride crystallizes in space groupP2 1 /n(#14) with the following parameters:a= 12.67477(7),b= 10.44076(5),c= 20.38501(12) Å,β= 93.1438(7)°,V= 2693.574(18) Å 3 , andZ= 4 at 295 K. The crystal structure consists of stacks of molecules along theb-axis, and the stacks contain chains of strong N–H⋯Cl hydrogen bonds. One density functional theory calculation moved a proton from an N atom to the Cl, but another calculation yielded a more chemically reasonable result. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®)

Materials Science↗
DOE OSTI2022

Crystal structure of vismodegib, C 19 H 14 Cl 2 N 2 O 3 S

The crystal structure of vismodegib has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional theory techniques. Vismodegib crystallizes in space group P2 1 /a (#14) with a = 16.92070(20), b = 10.20235(4), c = 12.16161(10) Å, β = 108.6802(3)°, V = 1988.873(9) Å 3 , and Z = 4. The crystal structure consists of corrugated layers of molecules parallel to the bc-plane. There is only one classical hydrogen bond in the structure, between the amide nitrogen atom and the N atom of the pyridine ring. Pairs of these hydrogen bonds link the molecules into dimers, with a graph set R2,2(14) > a > a. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®).

36 MATERIALS SCIENCE↗
DOE OSTI2024

Observation of Thermally Induced Piezomagnetic Switching in Cu 2 OSeO 3 Polymorph Synthesized under High-Pressure

A polymorph of Cu 2 OSeO 3 with the distorted kagome lattice is successfully obtained using the high-pressure synthesis technique (Cu 2 OSeO 3 -HP). The structural analysis using X-ray and neutron powder diffraction suggests that the tetrahedral Cu 2+ clusters [similar to those in Cu 2 OSeO 3 ambient-pressure phase (Cu 2 OSeO 3 -AP)] exist in Cu 2 OSeO 3 -HP but with three symmetry inequivalent sites. No structural change is observed between 1.5 K and the room temperature. The complex magnetic H-T phase diagram is established based on the temperature- and field-dependent magnetization data, indicating two distinct antiferromagnetic phases at low and intermediate temperatures, in addition to the higher-temperature spin-glass-like phase. The low temperature phase is identified by neutron powder diffraction refinements as a canted noncollinear antiferromagnetic order with a weak ferromagnetic component along the b-axis. Size of the refined ordered moment is ≈1.00(4) µ B in Cu 2 OSeO 3 -HP, indicating a large enhancement compared to that of Cu 2 OSeO 3 -AP (≈0.61 µ B ). By applying a uniaxial stress, finite enhancement of weak ferromagnetic component in the noncollinear antiferromagnetic phase in Cu 2 OSeO 3 -HP is observed, which is the clear evidence of the piezomagnetic effect. Interestingly, the sign of the induced magnetization changes on heating from the low-temperature to the intermediate-temperature phases, indicating a novel piezomagnetic switching effect in this compound.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Crystal structure of terazosin hydrochloride dihydrate (Hytrin ® ), C 19 H 26 N 5 O 4 Cl(H 2 O) 2

The crystal structure of terazosin hydrochloride dihydrate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Terazosin hydrochloride dihydrate crystallizes in space group P- 1 (#2) with a = 10.01402(4), b = 10.89995(4), c = 11.85357(4) Å, α = 89.5030(3), β = 71.8503(3), γ = 66.5632(2)°, V = 1118.143(8) Å 3 , and Z = 2. The terazosin cation occurs in an extended conformation. The crystal structure is dominated by hydrogen bonds. The most notable are the O–H···Cl from the water molecules to the chloride anion and N–H···Cl from the protonated ring nitrogen to the chloride. The amino group donates protons to each of the two water molecules. The powder pattern has been submitted to ICDD ® for inclusion in the Powder Diffraction File™.

Wheatley, Austin M.↗
DOE OSTI2024

Crystal structure of valbenazine, C 24 H 38 N 2 O 4

The crystal structure of valbenazine has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Valbenazine crystallizes in space groupP2 1 2 1 2 1 (#19) witha= 5.260267(17),b= 17.77028(7),c= 26.16427(9) Å,V= 2445.742(11) Å 3 , andZ= 4 at 295 K. The crystal structure consists of discrete molecules and the mean plane of the molecules is approximately (8,−2,15). There are no obvious strong intermolecular interactions. There is only one weak classical hydrogen bond in the structure, from the amino group to the ether oxygen atom. Two intramolecular and one intermolecular C–H⋯O hydrogen bonds also contribute to the lattice energy. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®)

Materials Science↗
DOE OSTI2021

Canting of the Magnetic Moments on the Octahedral Site of an Iron Oxide Garnet in Response to Diamagnetic Cation Substitution

Using neutron powder diffraction and magnetic susceptibility measurements, we report on the preparation and characterization of the temperature- and field-dependent properties of CaY2ZrFe4O12, a composition closely related to the high-temperature ferrimagnet Y3Fe5O12. By diluting the concentration of paramagnetic ions on the octahedral sublattice of the garnet structure, we find temperature-dependent canting of the magnetic moments. This reflects the importance of the octahedral sublattice in mediating the magnetic interactions between the tetrahedral sites and offers insight into a large number of competing magnetic interactions in the garnet structure.

Milam-Guerrero, JoAnna↗
DOE OSTI2016

Crystal structure of norgestimate, C23H31NO3

The crystal structure of norgestimate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Norgestimate crystallizes in space group P 2 1 2 1 2 1 (#19) with a = 11.523 67(9), b = 16.130 72(20), c = 22.247 93(20) Å, V = 4135.56(7) Å 3 , and Z = 8. There are two independent molecules in the asymmetric unit, with opposite conformations of the acetate groups. Molecule 2 is 7.3 kcal mole -1 lower in energy than molecule 1, and is in the minimum energy conformation. The hydroxyimine groups form O–H∙∙∙O hydrogen bonds to the acetate carbonyl groups, resulting in two separate C(15) chains along the b -axis. The powder pattern is included in the Powder Diffraction File ™ as entry 00-064-1503.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Crystal structure of encorafenib, C 22 H 27 ClFN 7 O 4 S

The crystal structure of encorafenib, C 22 H 27 ClFN 7 O 4 S, has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional theory techniques. Encorafenib crystallizes in space group P2 1 (#4) with a = 16.17355(25), b = 9.52334(11), c = 17.12368(19) Å, β = 89.9928(22)°, V = 2637.50(4) Å 3 , and Z = 4. The crystal structure consists of alternating layers of stacked halogenated phenyl rings and the other parts of the molecules perpendicular to the a-axis. One molecule participates in two strong N–H∙∙∙N hydrogen bonds (one intra- and the other intermolecular), which are not present for the other molecule. The intermolecular hydrogen bonds link molecule 2 into a spiral chain along the b-axis. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®).

36 MATERIALS SCIENCE↗
DOE OSTI2024

Crystal structure of anthraquinone-2-carboxylic acid, C 15 H 8 O 4

The crystal structure of anthraquinone-2-carboxylic acid has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional theory techniques. Anthraquinone-2-carboxylic acid crystallizes in space groupP-1 (#2) witha= 3.7942(2),b= 13.266(5),c= 22.835(15) Å,α= 73.355(30),β= 89.486(6),γ= 86.061(1)°,V= 1098.50(7) Å 3 , andZ= 4. The crystal structure contains two independent molecules of anthraquinone-2-carboxylic acid. Although the expected hydrogen-bonded dimers are present, the dimers are not centrosymmetric. The dimer contains one molecule of each planar low-energy conformation. The crystal structure consists of a herringbone array of centrosymmetric pairs of molecules parallel to thebc-plane. The molecules stack along the shorta-axis. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).

Materials Science↗
DOE OSTI2018

Crystal structure of lubiprostone Polymorph B, C 20 H 32 F 2 O 5

The crystal structure of lubiprostone has been refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Lubiprostone crystallizes in space group P 1 (#1) with a = 9.02025(2), b = 10.72121(2), c = 12.32817(4) Å, α = 78.5566(2), β = 69.6858(2), γ = 77.3292(2)°, V = 1081.069(3) Å 3 , and Z = 2. The two independent molecules occur in an extended conformation, aligned approximately along the c -axis. The hydrophobic side chains are adjacent to each other, resulting in layers parallel to the ac plane. The two carboxylic acid groups form an eight-membered ring, resulting in dimers of the two independent molecules. Each hydroxyl group acts as a hydrogen bond donor to the ketone of the fused ring system. The powder pattern is included in the Powder Diffraction File™ as entry 00-066-1622.

Kaduk, James A. (ORCID:000000016610541X)↗
DOE OSTI2015

Pressure-Induced Structural Phase Transition in CeNi: X-ray and Neutron Scattering Studies and First-Principles Calculations

The pressure-induced structural phase transition in the intermediate-valence compound CeNi has been investigated by x-ray and neutron powder diffraction techniques. It is shown that the structure of the pressure-induced CeNi phase (phases) can be described in terms of the Pnma space group. Equations of state for CeNi on both sides of the phase transition are derived and an approximate P-T phase diagram is suggested for P<8 GPa and T<300 K. The observed Cmcm→Pnma structural transition is then analyzed using density functional theory calculations, which successfully reproduce the ground state volume, the phase transition pressure, and the volume collapse associated with the phase transition.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Novel bipyridinyl oxadiazole-based metal coordination complexes: High efficient and green synthesis of 3,4-dihydropyrimidin-2(1H)-ones through the Biginelli reactions

Three new metal coordination complexes, namely, [Co(BPO){sub 2}(H{sub 2}O){sub 4}](BS){sub 2}(H{sub 2}O){sub 2} (1), [Co(BPO){sub 2}(H{sub 2}O){sub 4}](ABS){sub 2}(H{sub 2}O){sub 2} (2), [Co(BPO){sub 2}(H{sub 2}O){sub 4}](MBS){sub 2}(H{sub 2}O){sub 2} (3) [BPO=2,5-di(pyridin-4-yl)-1,3,4-oxadiazole, BS=benzenesulphonate, ABS=4-aminobenzenesulphonate, MBS=4-methylbenzenesulphonate] were obtained under hydrothermal conditions. Complexes 1–3 were structurally characterized by single-crystal X-ray diffraction, powder X-ray diffraction, IR and thermogravimetric analyses (TGA). All of them display a zero-dimensional motif, in which strong intermolecular hydrogen bonding interactions (O–H···O/N) and packing interactions (C–H···π and π···π) make them achieve a three-dimensional supramolecular architecture. The primary catalytic results of these three complexes show that high efficiency for the green synthesis of a variety of 3,4-dihydropyrimidin-2(1H)-ones was observed under solvent free conditions through Biginelli reactions. The present catalytic protocols exhibit advantages such as excellent yield, easy isolation, eco-friendly conditions, and short reaction time. - Graphical abstract: Three new metal coordination complexes with bipyridinyl-oxadiazole were obtained under hydrothermal conditions, which display a zero-dimensional motif, and show high efficiency for the green synthesis of a variety of 3,4-dihydropyrimidin-2(1H)-ones under solvent free conditions through Biginelli reactions. The present catalytic protocols exhibit advantages such as excellent yield, easy isolation, eco-friendly conditions, and short reaction time. Display Omitted.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Crystal structure of nicarbazin, (C 13 H 10 N 4 O 5 )(C 6 H 8 N 2 O)

The crystal structure of nicarbazin has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Nicarbazin is a co-crystal of 4,4′-dinitrocarbanilide (DNC) and 2-hydroxy-4,6-dimethylpyrimidine (HDP) molecules. Nicarbazin crystallizes in space groupP-1(#2) witha= 6.90659(8),b= 12.0794(4),c= 13.5040(7) Å,α= 115.5709(11),β= 102.3658(6),γ= 91.9270(4)°,V= 982.466(5) Å 3 , andZ= 2. The DNC and HDP molecules are linked by two strong N–H⋯O and N–H⋯N hydrogen bonds, and the HDP molecules are linked into centrosymmetric dimers by another N–H⋯O hydrogen bond. These strong hydrogen bonds link the molecules into layers parallel to theab-plane and parallel stacking of both DNC and HDP molecules is prominent in the structure. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®).

Materials Science↗