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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,027 records · Page 57
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

The crystal structure of TlMgCl 3 from 290 K to 725 K

The title compound, thallium magnesium trichloride, has been identified as a scintillator with both moderate gamma-stopping power and moderate light yield. Knowledge of its crystal structure is needed for further development. This work determines the crystal structure of TlMgCl 3 to be hexa­gonal P6 3 /mmc (No. 194) and isostructural with RbMgCl 3 , contrary to previously reported data. This structure was obtained by single-crystal X-ray diffraction and was further confirmed by neutron diffraction measurements. Extending neutron diffraction measurements to high temperature, the data show that TlMgCl 3 maintains this crystal structure from 290 K up through 725 K, approaching the melting point of 770 K. Anisotropic thermal expansion coefficients increase over this temperature range, from 31 to 38 × 10 –6 K –1 along the a axis and from 19 to 34 × 10 –6 K –1 along the c axis.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Structural and spectral dynamics of single-crystalline Ruddlesden-Popper phase halide perovskite blue light-emitting diodes

Achieving perovskite-based high–color purity blue-emitting light-emitting diodes (LEDs) is still challenging. Here, we report successful synthesis of a series of blue-emissive two-dimensional Ruddlesden-Popper phase single crystals and their high–color purity blue-emitting LED demonstrations. Although this approach successfully achieves a series of bandgap emissions based on the different layer thicknesses, it still suffers from a conventional temperature-induced device degradation mechanism during high-voltage operations. To understand the underlying mechanism, we further elucidate temperature-induced device degradation by investigating the crystal structural and spectral evolution dynamics via in situ temperature-dependent single-crystal x-ray diffraction, photoluminescence (PL) characterization, and density functional theory calculation. The PL peak becomes asymmetrically broadened with a marked intensity decay, as temperature increases owing to [PbBr 6 ] 4- octahedra tilting and the organic chain disordering, which results in bandgap decrease. This study indicates that careful heat management under LED operation is a key factor to maintain the sharp and intense emission.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Diverse high-pressure chemistry in Y-NH 3 BH 3 and Y–paraffin oil systems

The yttrium-hydrogen system has gained attention because of near-ambient temperature superconductivity reports in yttrium hydrides at high pressures. We conducted a study using synchrotron single-crystal x-ray diffraction (SCXRD) at 87 to 171 GPa, resulting in the discovery of known (two YH3 phases) and five previously unknown yttrium hydrides. These were synthesized in diamond anvil cells by laser heating yttrium with hydrogen-rich precursors—ammonia borane or paraffin oil. The arrangements of yttrium atoms in the crystal structures of new phases were determined on the basis of SCXRD, and the hydrogen content estimations based on empirical relations and ab initio calculations revealed the following compounds: Y 3 H 11 , Y 2 H 9 , Y 4 H 23 , Y 13 H 75 , and Y 4 H 25 . The study also uncovered a carbide (YC 2 ) and two yttrium allotropes. Complex phase diversity, variable hydrogen content in yttrium hydrides, and their metallic nature, as revealed by ab initio calculations, underline the challenges in identifying superconducting phases and understanding electronic transitions in high-pressure synthesized materials.

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

Berkelium–carbon bonding in a tetravalent berkelocene

Interest in actinide–carbon bonds has persisted since actinide organometallics were first investigated for applications in isotope separation during the Manhattan Project. Transplutonium organometallics are rarely isolated and structurally characterized, likely owing to limited isotope inventories, a scarcity of suitable laboratory infrastructure, and intrinsic difficulties with the anaerobic conditions required. In this paper, we report the discovery of an organometallic “berkelocene” complex prepared from 0.3 milligrams of berkelium-249. Single-crystal x-ray diffraction shows a tetravalent berkelium ion between two substituted cyclooctatetraene ligands, resulting in the formation of berkelium–carbon bonds. The coordination in berkelocene resembles that of uranocene, and calculations show that the berkelium 5f orbitals engage in covalent overlap with the δ-symmetry orbitals of the cyclooctatetraenide ligand π system. Charge transfer from the ligands is diminished relative to uranocene and other actinocenes, which maximizes contributions from the stable, half-filled 5f 7 configuration of tetravalent berkelium.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Synthesis, structural characterization, and DFT calculations of 3-buthyl-4-(3-methyl-3-mesitylcyclobut-1-yl)-1,3-thiazole-2(3H)-thione

The title compound, C{sub 21}H{sub 29}NS{sub 2}, has been synthesized and its crystal structure has been determined from single crystal X-ray diffraction data. Crystals are monoclinic, a = 11.4923(8), b = 13.1842(7), c = 14.6583(8) Å, β = 109.983(6)°, sp. gr. P2{sub 1}/c, Z = 4. Mesityl and thiazole groups are in cis positions with respect to the cyclobutane ring. The cyclobutane ring is puckered, with a dihedral angle of 26.6(2)° between the two three-atom planes. The crystal structure involves one weak intermolecular C–H···S hydrogen-bond. The molecular geometry was also optimized using density functional theory (DFT/B3LYP) method with the 6-311G(d, p) basis set in ground state. Geometric parameters (bond lengths, bond angles and torsion angles) and vibrational assignments have been calculated theoretically and compared with the experimental data.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2016

Crystal structure of (E)-3-fluoro-N-((5-nitrothiophen-2-yl)methylene)aniline

The structure of the title compound C{sub 11}H{sub 7}FN{sub 2}O{sub 2}S was characterized by single crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P2{sub 1}/n with Z = 12, i.e. with three molecules in asymmetric unit. The molecules are not planar: the dihedral angles between the planes of thiophene and the benzene rings are 42.3(3)°, 42.0(3)°, and 48.9(2)°. In the crystal, intermolecular C–H···F interactions link the molecules through R{sub 2}{sup 2} (14) ring motif. The crystal packing is also stabilized by π···π interactions.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2016

Crystal structure and packing analysis of nitrofurantoin N,N-dimethylformamide solvate

The N, N′-dimethylformamide solvated crystal of the drug nitrofurantoin has been prepared and analysed by single-crystal X-ray diffraction. The two co-crystallized molecules, in the 1 : 1 stoichiometric ratio, are linked by a medium/strong N–H···O hydrogen bond (N···O is 2.759 (3) Å) and a weaker C–H···O interaction to form isolated supramolecular adducts, that in turn are packed into the lattice framework mainly through C–H···O hydrogen bonds. Two-dimensional fingerprint plots of Hirshfeld surfaces are used to visualize, analyze and compare intermolecular interactions found in the title compound and in similar structures.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2016

Two new coordination polymers based on tartaric acid ligand: Syntheses, crystal structure and thermal stability

Two new coordination polymers [Cd{sub 3}(D-Tar){sub 3}]{sub n} (1) and [Pb(meso-Tar)]{sub n} (2) (H{sub 2}Tar = tartaric acid) have been synthesized by hydrothermal reaction and characterized by single crystal X-ray diffraction analysis and IR spectra. 1 crystallizes in the C222{sub 1} chiral space group and shows a 3D (4,4)-connected net with the (4.6.8{sup 4}){sub 4}(4.6{sup 2}.8{sup 2}.10)(4.6{sup 2}.8{sup 3})(4.6{sup 3}.8{sup 2})(4.6{sup 3}.8{sup 2}){sub 4}(4.8{sup 5}){sub 2} topology. 2 possesses a 3D (4,4)-connected net with the (4{sup 3}.6{sup 2}.8) topology. In addition, the thermogravimetric analyses (TGA) results for polymers are discussed.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2016

Synthesis, antityrosinase activity of curcumin analogues, and crystal structure of (1E,4E)-1,5-bis(4-ethoxyphenyl)penta-1,4-dien-3-one

Five derivatives of curcumin analogue (R = OCH{sub 2}CH{sub 3} (1), R = N(CH{sub 3}){sub 2} (2), R = 2,4,5-OCH{sub 3} (3), R = 2,4,6-OCH{sub 3} (4), and R = 3,4,5-OCH{sub 3} (5)) were synthesized and characterized by {sup 1}H NMR, FT-IR and UV–Vis spectroscopy. The synthesized derivatives were screened for antityrosinase activity, and found that 4 and 5 possess such activity. The crystal structure of 1 was determined by single crystal X-ray diffraction: monoclinic, sp. gr. P2{sub 1}/c, a = 17.5728(15) Å, b = 5.9121(5) Å, c = 19.8269(13) Å, β = 121.155(5)°, Z = 4. The molecule 1 is twisted with the dihedral angle between two phenyl rings being 15.68(10)°. In the crystal packing, the molecules 1 are linked into chains by C−H···π interactions and further stacked by π···π interactions with the centroid–centroid distance of 3.9311(13) Å.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2017

A three-dimensional coordination polymer based on 1,2,3-triazole-4,5-dicarboxylic acid (H{sub 3}tda): ([Cd{sub 12}(tda){sub 8}(H{sub 2}O){sub 11}] · (H{sub 2}O)6.25){sub n}

The title coordination polymer ([Cd{sub 12}(tda){sub 8}(H{sub 2}O){sub 11}] · (H{sub 2}O){sub 6.25}){sub n} (H{sub 3}tda = 1,2,3-triazole-4,5-dicarboxylic acid), has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Complex crystallizes in orthorhombic sp. gr. Pmn2{sub 1} with Z = 4. The Cd{sub 2} unit doublebridged by one carboxylate oxygen atom and two neighboring nitrogen atoms from the tda{sup 3–} ligands are linked by the tda{sup 3–}ligands to lead to the 2D (4,4) network in the ac plane. The almost coplanar Cd{sub 2}(μ{sub 5}-tda){sub 2} unit comprised of two Cd ions double-bridged by two tda{sup 3–} ligands through the neighboring nitrogen atoms is connected with the other four Cd{sub 2}(μ{sub 5}-tda){sub 2} units form the undulating 2D network in the ac plane. The (4,4) networks and undulating 2D networks are alternatively connected along the b axis by the tda{sup 3–} ligands coordinating to the Cd ions to form the 3D framework.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2017

Experimental (X-ray, FT-IR, and UV-Vis Spectroscopy) and Theoretical Methods (DFT Study) of N'-(Dipyridin-2-ylmethylene)-4-methylbenzenesulfonohydrazide

A new hydrazone derivative was synthesized and characterized by IR, UV-Vis spectroscopy, elemental analysis and single-crystal X-ray diffraction. The compound was established to reveal antibacterial activity. The compound (C{sub 18}H{sub 16}N{sub 4}O{sub 2}S) crystallizes in monoclinic crystal system with C2/c space group. The molecular structure is stabilized by a C–H···O intermolecular hydrogen bond. Quantum chemical calculations based on DFT/B3LYP/6-31G(d, p) were carried out and the results were compared with the experimental data. The calculated vibrational frequencies were used to determine the types of molecular motions associated with each of the observed experimental bands. UV-Vis absorption spectra of the compound calculated by TD-DFT have been ascribed to their corresponding molecular structure and electron transitions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Synthesis and Structural Analysis of 2-Cyanophenyl Phenacyl Ether

Molecular and crystal structure of 2-cyanophenyl phenacyl ether, C{sub 15}H{sub 11}O{sub 2}N, have been determined by single crystal X-ray diffraction study. The title compound is monoclinic, with a = 4.4334(4) Å, b = 10.7677(11) Å, c = 12.7779(11) Å, β = 99.806(8)°, Z = 2, sp. gr. P2{sub 1}. The crystal structure is stabilized by C–H···O inter-molecular interactions. In order to clarify the electron delocalization on the whole molecule and determine the active sites of the title compound, DFT calculations and NBO analysis were performed.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Synthesis, Spectroscopy, and α-Glucosidase Inhibitory Activity of 3-Substituted Hydrazone Derivatives and Crystal Structure of (1E,2E)-1,2-Bis[1-(3-methoxyphenyl)ethylidene]hydrazone

Six 3-substituted hydrazone derivatives [R = −OCH{sub 3} (1), −NH{sub 2} (2), −NO{sub 2} (3), −F (4), −Cl (5), and −Br (6)] were synthesized by condensation reaction. Their structures were elucidated by {sup 1}H NMR, FT-IR and UV-Vis spectroscopy. The synthesized compounds were further evaluated for their α-glucosidase inhibitory activity. Strong activity was found for 1 and 3. The crystal structure of 1 was determined by single crystal X-ray diffraction: a = 6.9743(1) Å, b = 18.3627(3) Å, c = 12.0207(2) Å, β = 96.087(1)o, sp. gr. P2{sub 1}/c, Z = 4. The molecule of 1 is twisted with the dihedral angle between the two phenyl rings being 51.91(4)°. In the crystal packing, the molecules are linked into chains by C–H···π interactions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Synthesis and Molecular Structure of 2-(4-Chlorophenyl)-3-(phenyl-amino)-5-(thiophen-2-ylmethylidene)-3,5-dihydro-4H-imidazol-4-one

2-(4-Chlorophenyl)-3-(phenylamino)-5-(thiophen-2-ylmethylidene)-3,5-dihydro-4H-imidazol-4-one, C{sub 20}H{sub 14}N{sub 3}OSCl was synthesized and its crystal structure was determined by single crystal X-ray diffraction. The crystals are triclinic, sp. gr. P1, Z = 2. All three rings are planar, and imidazole ring is almost perpendicular to the phenyl ring with the dihedral angle of 88.65(2)°. In the crystal, pairs of O–H···O hydrogen bonds link molecules into inversion dimers, featuring R{sub 22}(10) graph set motif. Crystal structure is further stabilized by π···π interactions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Hydrothermal Synthesis and Characterization of a New Strandberg-type Diphosphopentamolybdate (C{sub 6}N{sub 3}H{sub 18}){sub 2}[P{sub 2}Mo{sub 5}O{sub 23}] · 6H{sub 2}O

An inorganic-organic hybrid material formulated as (C{sub 6}N{sub 3}H{sub 18}){sub 2}[P{sub 2}Mo{sub 5}O{sub 23}] · 6H{sub 2}O, has been hydrothermally synthesized and characterized by single crystal X-ray diffraction technique, IR spectrum, thermogravimetric analysis and UV-visible spectroscopy. The structure consists of diphosphopentamolybdate Strandberg type polyoxoanions [P{sub 2}Mo{sub 5}O{sub 23}]{sup 6–}, protonated 1-(2-aminoethyl)piperazine cations and six crystallization water molecules. These anions are connected with the organic amine through hydrogen bonding interactions between the hydrogen atoms of the organic molecules and the oxygen atoms of the polyoxoanion and water molecules which generate a three-dimensional network.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

New Diphosphopentamolybdate K{sub 5}[HP{sub 2}Mo{sub 5}O{sub 23}] · 10H{sub 2}O: Synthesis, Structure, and Characterization

A new diphosphopentamolybdate(VI) K{sub 5}[HP{sub 2}Mo{sub 5}O{sub 23}] · 10H{sub 2}O has been prepared employing solution method and characterized by single crystal X-ray diffraction, energy dispersive analysis, infrared spectroscopy, thermal stability analysis, cyclic voltammetry analysis, and ultraviolet visible spectroscopy. The compound crystallizes in the orthorhombic sp. gr. Pcab: a = 15.9661(10) Å, b = 19.0832(10) Å, c = 20.0970(9) Å, V = 6123.27(10) Å3, Z = 8. The crystal structure contains the polyanion units [HP{sub 2}Mo{sub 5}O{sub 23}]{sup 5–} around the potassium cations and lattice water. The [HP{sub 2}Mo{sub 5}O{sub 23}]{sup 5–} subunits are connected together through K−O−Mo bridges and hydrogen bonds. The crystal shape morphology was simulated using the Bravais–Friedel–Donnay–Harker model.

36 MATERIALS SCIENCE↗