Structural characterization and aging of glassy pharmaceuticals made using acoustic levitation.

PubMed

Benmore, Chris J; Weber, J K R; Tailor, Amit N; Cherry, Brian R; Yarger, Jeffery L; Mou, Qiushi; Weber, Warner; Neuefeind, Joerg; Byrn, Stephen R

2013-04-01

Here, we report the structural characterization of several amorphous drugs made using the method of quenching molten droplets suspended in an acoustic levitator. (13) C NMR, X-ray, and neutron diffraction results are discussed for glassy cinnarizine, carbamazepine, miconazole nitrate, probucol, and clotrimazole. The (13) C NMR results did not find any change in chemical bonding induced by the amorphization process. High-energy X-ray diffraction results were used to characterize the ratio of crystalline to amorphous material present in the glasses over a period of 8 months. All the glasses were stable for at least 6 months except carbamazepine, which has a strong tendency to crystallize within a few months. Neutron and X-ray pair distribution function analyses were applied to the glassy materials, and the results were compared with their crystalline counterparts. The two diffraction techniques yielded similar results in most cases and identified distinct intramolecular and intermolecular correlations. The intramolecular scattering was calculated based on the crystal structure and fit to the measured X-ray structure factor. The resulting intermolecular pair distribution functions revealed broad-nearest and next-nearest neighbor molecule-molecule correlations. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:1290-1300, 2013. Copyright © 2013 Wiley Periodicals, Inc.

Speciation of platinum(IV) in nitric acid solutions.

PubMed

Vasilchenko, Danila; Tkachev, Sergey; Baidina, Iraida; Korenev, Sergey

2013-09-16

The speciation of platinum(IV) ions in nitric acid (6-15.8 M) solutions of H2[Pt(OH)6] has been studied by (195)Pt NMR and Raman spectroscopy. Series of aqua-hydroxo-nitrato complexes [Pt(L)(x)(NO3)(6-x)] (L = H2O or OH(-); x = 0, ..., 6) were found to exist in such solutions. The pair additivity model of chemical shifts and statistical theory were used to assign signals in NMR spectra to particular [Pt(L)(x)(NO3)(6-x)] species. Mononuclear hexanitratoplatinates(IV) have been isolated in solid state in substantial yield as pyridinium salt (PyH)2[Pt(NO3)6] and characterized by single-crystal X-ray diffraction. Aging of the platinum nitric acid solutions for more than 5-6 h results in oligomerization of [Pt(L)(x)(NO3)(6-x)] species and the formation of oligonuclear aqua-hydroxo-nitrato complexes with OH(-) and NO3(-) bridging ligands. Oligomeric platinum(IV) complexes with two and four nuclei were unambiguously detected by NMR on (195)Pt -enriched samples. Oligomers with even higher nuclearity were also detected. Dimeric anions [Pt2(μ-OH)2(NO3)8](2-) have been isolated as single crystals of tetramethylammonium salt and characterized by X-ray diffraction.

Difference in the structures of alanine tri- and tetra-peptides with antiparallel β-sheet assessed by X-ray diffraction, solid-state NMR and chemical shift calculations by GIPAW.

PubMed

Asakura, Tetsuo; Yazawa, Koji; Horiguchi, Kumiko; Suzuki, Furitsu; Nishiyama, Yusuke; Nishimura, Katsuyuki; Kaji, Hironori

2014-01-01

Alanine oligomers provide a key structure for silk fibers from spider and wild silkworms.We report on structural analysis of L-alanyl-L-alanyl-L-alanyl-L-alanine (Ala)4 with anti-parallel (AP) β-structures using X-ray and solid-state NMR. All of the Ala residues in the (Ala)4 are in equivalent positions, whereas for alanine trimer (Ala)3 there are two alternative locations in a unit cell as reported previously (Fawcett and Camerman, Acta Cryst., 1975, 31, 658-665). (Ala)4 with AP β-structure is more stable than AP-(Ala)3 due to formation of the stronger hydrogen bonds. The intermolecular structure of (Ala)4 is also different from polyalanine fiber structure, indicating that the interchain arrangement of AP β-structure changes with increasing alanine sequencelength. Furthermore the precise (1)H positions, which are usually inaccesible by X-ray diffraction method, are determined by high resolution (1)H solid state NMR combined with the chemical shift calculations by the gauge-including projector augmented wave method. Copyright © 2013 Wiley Periodicals, Inc.

A neutron-X-ray, NMR and calorimetric study of glassy Probucol synthesized using containerless techniques

NASA Astrophysics Data System (ADS)

Weber, J. K. R.; Benmore, C. J.; Tailor, A. N.; Tumber, S. K.; Neuefeind, J.; Cherry, B.; Yarger, J. L.; Mou, Q.; Weber, W.; Byrn, S. R.

2013-10-01

Acoustic levitation was used to trap 1-3 mm diameter drops of Probucol and other pharmaceutical materials in containerless conditions. Samples were studied in situ using X-ray diffraction and ex situ using neutron diffraction, NMR and DSC techniques. The materials were brought into non-equilibrium states by supersaturating solutions or by supercooling melts. The glass transition and crystallization temperatures of glassy Probucol were 29 ± 1 and 71 ± 1 °C respectively. The glassy form was stable with a shelf life of at least 8 months. A neutron/X-ray difference function of the glass showed that while molecular sub-groups remain rigid, many of the hydrogen correlations observed in the crystal become smeared out in the disordered material. The glass is principally comprised of slightly distorted Form I Probucol molecules with disordered packing rather than large changes in the individual molecular structure. Avoiding surface contact-induced nucleation provided access to highly non-equilibrium phases and enabled synthesis of phase-pure glasses.

Synthesis, X-ray diffraction method, spectroscopic characterization (FT-IR, 1H and 13C NMR), antimicrobial activity, Hirshfeld surface analysis and DFT computations of novel sulfonamide derivatives

NASA Astrophysics Data System (ADS)

Demircioğlu, Zeynep; Özdemir, Fethi Ahmet; Dayan, Osman; Şerbetçi, Zafer; Özdemir, Namık

2018-06-01

Synthesized compounds of N-(2-aminophenyl)benzenesulfonamide 1 and (Z)-N-(2-((2-nitrobenzylidene)amino)phenyl)benzenesulfonamide 2 were characterized by antimicrobial activity, FT-IR, 1H and 13C NMR. Two new Schiff base ligands containing aromatic sulfonamide fragment of (Z)-N-(2-((3-nitrobenzylidene)amino)phenyl)benzenesulfonamide 3 and (Z)-N-(2-((4-nitrobenzylidene)amino)phenyl)benzenesulfonamide 4 were synthesized and investigated by spectroscopic techniques including 1H and 13C NMR, FT-IR, single crystal X-ray diffraction, Hirshfeld surface, theoretical method analyses and by antimicrobial activity. The molecular geometry obtained from the X-ray structure determination was optimized Density Functional Theory (DFT/B3LYP) method with the 6-311++G(d,p) basis set in ground state. From the optimized geometry of the molecules of 3 and 4, the geometric parameters, vibrational wavenumbers and chemical shifts were computed. The optimized geometry results, which were well represented the X-ray data, were shown that the chosen of DFT/B3LYP 6-311G++(d,p) was a successful choice. After a successful optimization, frontier molecular orbitals, chemical activity, non-linear optical properties (NLO), molecular electrostatic mep (MEP), Mulliken population method, natural population analysis (NPA) and natural bond orbital analysis (NBO), which cannot be obtained experimentally, were calculated and investigated.

Structure of N-(5-ethyl-[1,3,4]-thiadiazole-2-yl)toluenesulfonamide by combined X-ray powder diffraction, 13C solid-state NMR and molecular modelling.

PubMed

Hangan, Adriana; Borodi, Gheorghe; Filip, Xenia; Tripon, Carmen; Morari, Cristian; Oprean, Luminita; Filip, Claudiu

2010-12-01

The crystal structure solution of the title compound is determined from microcrystalline powder using a multi-technique approach that combines X-ray powder diffraction (XRPD) data analysis based on direct-space methods with information from (13)C solid-state NMR (SSNMR), and molecular modelling using the GIPAW (gauge including projector augmented-wave) method. The space group is Pbca with one molecule in the asymmetric unit. The proposed methodology proves very useful for unambiguously characterizing the supramolecular arrangement adopted by the N-(5-ethyl-[1,3,4]-thiadiazole-2-yl)toluenesulfonamide molecules in the crystal, which consists of extended double strands held together by C-H···π non-covalent interactions.

The relationship between crystal structure and methyl and t-butyl group dynamics in van der Waals organic solids

NASA Astrophysics Data System (ADS)

Beckmann, Peter A.; Paty, Carol; Allocco, Elizabeth; Herd, Maria; Kuranz, Carolyn; Rheingold, Arnold L.

2004-03-01

We report x-ray diffractometry in a single crystal of 2-t-butyl-4-methylphenol (TMP) and low-frequency solid state nuclear magnetic resonance (NMR) proton relaxometry in a polycrystalline sample of TMP. The x-ray data show TMP to have a monoclinic, P21/c, structure with eight molecules per unit cell and two crystallographically inequivalent t-butyl group (C(CH3)3) sites. The proton spin-lattice relaxation rates were measured between 90 and 310 K at NMR frequencies of 8.50, 22.5, and 53.0 MHz. The relaxometry data is fitted with two models characterizing the dynamics of the t-butyl groups and their constituent methyl groups, both of which are consistent with the determined x-ray structure. In addition to presenting results for TMP, we review previously reported x-ray diffractometry and low-frequency NMR relaxometry in two other van der Waals solids which have a simpler structure. In both cases, a unique model for the reorientational dynamics was found. Finally, we review a similar previously reported analysis in a van der Waals solid with a very complex structure in which case fitting the NMR relaxometry requires very many parameters and serves mainly as a flag for a careful x-ray diffraction study.

Membrane lateral compressibility determined by NMR and x-ray diffraction: effect of acyl chain polyunsaturation.

PubMed Central

Koenig, B W; Strey, H H; Gawrisch, K

1997-01-01

The elastic area compressibility modulus, Ka, of lamellar liquid crystalline bilayers was determined by a new experimental approach using 2H-NMR order parameters of lipid hydrocarbon chains together with lamellar repeat spacings measured by x-ray diffraction. The combination of NMR and x-ray techniques yields accurate determination of lateral area per lipid molecule. Samples of saturated, monounsaturated, and polyunsaturated phospholipids were equilibrated with polyethylene glycol (PEG) 20,000 solutions in water at concentrations from 0 to 55 wt % PEG at 30 degrees C. This procedure is equivalent to applying 0 to 8 dyn/cm lateral pressure to the bilayers. The resulting reductions in area per lipid were measured with a resolution of +/-0.2 A2 and the fractional area decrease was proportional to applied lateral pressure. For 1,2-dimyristoyl(d54)-sn-glycero-3-phosphocholine, 1-stearoyl(d35)-2-oleoyl-sn-glycero-3-phosphocholine (SOPC-d35), and 1-stearoyl(d35)-2-docosahexaenoyl-sn-glycero-3-phosphocholine (SDPC-d35) cross-sectional areas per molecule in excess water of 59.5, 61.4, and 69.2 A2 and bilayer elastic area compressibility moduli of 141, 221, and 121 dyn/cm were determined, respectively. Combining NMR and x-ray results enables the determination of compressibility differences between saturated and unsaturated hydrocarbon chains. In mixed-chain SOPC-d35 both chains have similar compressibility moduli; however, in mixed-chain polyunsaturated SDPC-d35, the saturated stearic acid chain appears to be far less compressible than the polyunsaturated docosahexaenoic acid chain. Images FIGURE 3 FIGURE 5 PMID:9336191

[Physicochemical properties of suplatast tosilate racemate and enantiomers].

PubMed

Ushio, T; Endo, K; Yamamoto, K

1996-11-01

The physicochemical properties of the enantiomer and racemates of suplatast tosilate (ST) were investigated by means of infrared spectroscopy, solid-state 13C CP/MAS NMR spectroscopy, thermal analysis, and X-ray diffraction analysis, and by measuring the solubility and hygroscopy. The infrared and NMR spectra and X-ray diffraction pattern of the enantiomer were distinctly different from those of the racemate. The melting point of the enantiomer was lower than that of the racemate by 5 degrees C, while the solubility of the enantiomer was 1.3 times higher than that of the racemate. The hygroscopic rate of the enantiomer was greater than that of the racemate. These results suggested that ST was classified into a racemic compound crystal. Furthermore, by comparing the relative peak intensity ratios on X-ray diffraction patterns of the crystals with various optical purities prepared by recrystallization, it was found that a mixture of racemic compound crystals and either of racemic mixture crystals or racemic solid solutions was obtained by recrystallization of ST in the content of 0 to 64%ee, while the recrystallization of ST in the content of more than 64%ee led to the formation of racemic mixture crystals or racemic solid solutions.

Solvent and temperature effects on crambin, a hydrophobic protein

DOE Office of Scientific and Technical Information (OSTI.GOV)

Llinas, M.; Lecomte, J.T.J.; De Marco, A.

1980-10-01

Crambin, a 5000-mol. wt. water-insoluble protein found in crambe abyssinica seeds is presently being studied by x-ray diffraction to 0.9 A resolution and /sup 1/H-nuclear magnetic resonance (NMR) spectroscopy. Preliminary /sup 1/H-NMR data at 250 and 600 MHz have suggested that this hydrophobic protein retains a similar globular conformation in both glacial acetic acid (AA), a Bronsted acid, and dimethylformamide (DMF), a Lewis base. These observations suggest that the globular conformation observed in these organic solvents is most likely the native structure present in the crystalline state. As suggested by the high intrinsic resolution of the crystallographic x-ray diffraction pattern,more » and demonstrated by the NMR data, crambin is a very rigid protein. Work is in progress to assign the /sup 1/H-resonances and to correlate H and /sup 13/C NMR dynamic data with the crystallographic model. It is hoped that unravelling conformational features of this hydrophobic protein will provide clues to help us understand other membrane-bound functional proteins.« less

Exploiting the Synergy of Powder X-ray Diffraction and Solid-State NMR Spectroscopy in Structure Determination of Organic Molecular Solids

PubMed Central

2013-01-01

We report a strategy for structure determination of organic materials in which complete solid-state nuclear magnetic resonance (NMR) spectral data is utilized within the context of structure determination from powder X-ray diffraction (XRD) data. Following determination of the crystal structure from powder XRD data, first-principles density functional theory-based techniques within the GIPAW approach are exploited to calculate the solid-state NMR data for the structure, followed by careful scrutiny of the agreement with experimental solid-state NMR data. The successful application of this approach is demonstrated by structure determination of the 1:1 cocrystal of indomethacin and nicotinamide. The 1H and 13C chemical shifts calculated for the crystal structure determined from the powder XRD data are in excellent agreement with those measured experimentally, notably including the two-dimensional correlation of 1H and 13C chemical shifts for directly bonded 13C–1H moieties. The key feature of this combined approach is that the quality of the structure determined is assessed both against experimental powder XRD data and against experimental solid-state NMR data, thus providing a very robust validation of the veracity of the structure. PMID:24386493

Exploiting the Synergy of Powder X-ray Diffraction and Solid-State NMR Spectroscopy in Structure Determination of Organic Molecular Solids.

PubMed

Dudenko, Dmytro V; Williams, P Andrew; Hughes, Colan E; Antzutkin, Oleg N; Velaga, Sitaram P; Brown, Steven P; Harris, Kenneth D M

2013-06-13

We report a strategy for structure determination of organic materials in which complete solid-state nuclear magnetic resonance (NMR) spectral data is utilized within the context of structure determination from powder X-ray diffraction (XRD) data. Following determination of the crystal structure from powder XRD data, first-principles density functional theory-based techniques within the GIPAW approach are exploited to calculate the solid-state NMR data for the structure, followed by careful scrutiny of the agreement with experimental solid-state NMR data. The successful application of this approach is demonstrated by structure determination of the 1:1 cocrystal of indomethacin and nicotinamide. The 1 H and 13 C chemical shifts calculated for the crystal structure determined from the powder XRD data are in excellent agreement with those measured experimentally, notably including the two-dimensional correlation of 1 H and 13 C chemical shifts for directly bonded 13 C- 1 H moieties. The key feature of this combined approach is that the quality of the structure determined is assessed both against experimental powder XRD data and against experimental solid-state NMR data, thus providing a very robust validation of the veracity of the structure.

Synthesis and Characterization of Single-Source Molecular Precursors to Binary Metal Sulphides: Bis(Diethyldithiocarbamato) M(II)Trialkylphosphine (M=Zn and Cd) Adducts

DTIC Science & Technology

1994-05-06

while the heterobimetallic species, 7, thermally decomposed to give00 crystalline ZnO.5S according to X-ray powder diffraction data. A. SUBJECT TERMS 15... heterobimetallic species, 7, thermally decomposed to give crystalline ZnO.5CdO.5S according to X-ray powder diffraction data. LaGOSSIOn "or OTIS RA&I VT-iC TAB EU...on the NMR timescale, and a single heterobimetallic species. Attempts to distinguish these possibilities are described later. The variable temperature

The potential for the indirect crystal structure verification of methyl glycosides based on acetates' parent structures: GIPAW and solid-state NMR approaches

NASA Astrophysics Data System (ADS)

Szeleszczuk, Łukasz; Gubica, Tomasz; Zimniak, Andrzej; Pisklak, Dariusz M.; Dąbrowska, Kinga; Cyrański, Michał K.; Kańska, Marianna

2017-10-01

A convenient method for the indirect crystal structure verification of methyl glycosides was demonstrated. Single-crystal X-ray diffraction structures for methyl glycoside acetates were deacetylated and subsequently subjected to DFT calculations under periodic boundary conditions. Solid-state NMR spectroscopy served as a guide for calculations. A high level of accuracy of the modelled crystal structures of methyl glycosides was confirmed by comparison with published results of neutron diffraction study using RMSD method.

Synthesis, characterization, and photophysical properties of a thiophene-functionalized bis(pyrazolyl) pyridine (BPP) tricarbonyl rhenium(I) complex.

PubMed

Lytwak, Lauren A; Stanley, Julie M; Mejía, Michelle L; Holliday, Bradley J

2010-09-07

A bromo tricarbonyl rhenium(I) complex with a thiophene-functionalized bis(pyrazolyl) pyridine ligand (L), ReBr(L)(CO)(3) (1), has been synthesized and characterized by variable temperature and COSY 2-D (1)H NMR spectroscopy, single-crystal X-ray diffraction, and photophysical methods. Complex 1 is highly luminescent in both solution and solid-state, consistent with phosphorescence from an emissive (3)MLCT excited state with an additional contribution from a LC (3)(pi-->pi*) transition. The single-crystal X-ray diffraction structure of the title ligand is also reported.

Observing the overall rocking motion of a protein in a crystal

NASA Astrophysics Data System (ADS)

Ma, Peixiang; Xue, Yi; Coquelle, Nicolas; Haller, Jens D.; Yuwen, Tairan; Ayala, Isabel; Mikhailovskii, Oleg; Willbold, Dieter; Colletier, Jacques-Philippe; Skrynnikov, Nikolai R.; Schanda, Paul

2015-10-01

The large majority of three-dimensional structures of biological macromolecules have been determined by X-ray diffraction of crystalline samples. High-resolution structure determination crucially depends on the homogeneity of the protein crystal. Overall `rocking' motion of molecules in the crystal is expected to influence diffraction quality, and such motion may therefore affect the process of solving crystal structures. Yet, so far overall molecular motion has not directly been observed in protein crystals, and the timescale of such dynamics remains unclear. Here we use solid-state NMR, X-ray diffraction methods and μs-long molecular dynamics simulations to directly characterize the rigid-body motion of a protein in different crystal forms. For ubiquitin crystals investigated in this study we determine the range of possible correlation times of rocking motion, 0.1-100 μs. The amplitude of rocking varies from one crystal form to another and is correlated with the resolution obtainable in X-ray diffraction experiments.

Synthesis, structural characterization and theoretical studies of a new Schiff base 4-(((3-(tert-Butyl)-(1-phenyl)pyrazol-5-yl) imino)methyl)phenol

NASA Astrophysics Data System (ADS)

Cuenú, Fernando; Londoño-Salazar, Jennifer; Torres, John Eduard; Abonia, Rodrigo; D'Vries, Richard F.

2018-01-01

4-(((3-(tert-Butyl)-(1-phenyl)pyrazol-5-yl)imino)methyl)phenol (4-OHFPz) was synthesized and characterized by FT-IR, MS, NMR, and single-crystal X-ray diffraction. Optimization of molecular geometry, vibrational frequencies, and chemical shifts were calculated by using the methods of density functional theory (DFT) with B3LYP and B3PW91 as functionals and Hartree-Fock with 6-311G++(d,p) as basis set using the GAUSSIAN 09 program package. With the VEDA 4 software, the vibrational frequencies were assigned in terms of the potential energy distribution (PED). The equilibrium geometries calculated by all methods were compared with X-ray diffraction results, indicating that the theoretical results matches well with the experimental ones. The data obtained from the vibrational analysis and the calculated NMR are consistent with the experimental spectra.

Hydrogen Atomic Positions of O-H···O Hydrogen Bonds in Solution and in the Solid State: The Synergy of Quantum Chemical Calculations with ¹H-NMR Chemical Shifts and X-ray Diffraction Methods.

PubMed

Siskos, Michael G; Choudhary, M Iqbal; Gerothanassis, Ioannis P

2017-03-07

The exact knowledge of hydrogen atomic positions of O-H···O hydrogen bonds in solution and in the solid state has been a major challenge in structural and physical organic chemistry. The objective of this review article is to summarize recent developments in the refinement of labile hydrogen positions with the use of: (i) density functional theory (DFT) calculations after a structure has been determined by X-ray from single crystals or from powders; (ii) ¹H-NMR chemical shifts as constraints in DFT calculations, and (iii) use of root-mean-square deviation between experimentally determined and DFT calculated ¹H-NMR chemical shifts considering the great sensitivity of ¹H-NMR shielding to hydrogen bonding properties.

A combined solid-state NMR and X-ray crystallography study of the bromide ion environments in triphenylphosphonium bromides.

PubMed

Burgess, Kevin M N; Korobkov, Ilia; Bryce, David L

2012-04-27

Multinuclear ((31)P and (79/81)Br), multifield (9.4, 11.75, and 21.1 T) solid-state nuclear magnetic resonance experiments are performed for seven phosphonium bromides bearing the triphenylphosphonium cation, a molecular scaffold found in many applications in chemistry. This is undertaken to fully characterise their bromine electric field gradient (EFG) tensors, as well as the chemical shift (CS) tensors of both the halogen and the phosphorus nuclei, providing a rare and novel insight into the local electronic environments surrounding them. New crystal structures, obtained from single-crystal X-ray diffraction, are reported for six compounds to aid in the interpretation of the NMR data. Among them is a new structure of BrPPh(4), because the previously reported one was inconsistent with our magnetic resonance data, thereby demonstrating how NMR data of non-standard nuclei can correct or improve X-ray diffraction data. Our results indicate that, despite sizable quadrupolar interactions, (79/81)Br magnetic resonance spectroscopy is a powerful characterisation tool that allows for the differentiation between chemically similar bromine sites, as shown through the range in the characteristic NMR parameters. (35/37)Cl solid-state NMR data, obtained for an analogous phosphonium chloride sample, provide insight into the relationship between unit cell volume, nuclear quadrupolar coupling constants, and Sternheimer antishielding factors. The experimental findings are complemented by gauge-including projector-augmented wave (GIPAW) DFT calculations, which substantiate our experimentally determined strong dependence of the largest component of the bromine CS tensor, δ(11), on the shortest Br-P distance in the crystal structure, a finding that has possible application in the field of NMR crystallography. This trend is explained in terms of Ramsey's theory on paramagnetic shielding. Overall, this work demonstrates how careful NMR studies of underexploited exotic nuclides, such as (79/81)Br, can afford insights into structure and bonding environments in the solid state. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Spectroscopy and crystal structures of natural stereoisomers of neoclerodane diterpenoids from Teucrium yemense of Saudi medicinal plant

NASA Astrophysics Data System (ADS)

Nur-e-Alam, Mohammad; Kanthasamy, Gopikkaa; Yousaf, Muhammad; Alqahtani, Ali S.; Ghabbour, Hazem A.; Al-Rehaily, Adnan J.

2017-11-01

3-O-deacetylteugracilin (1) and teugracilin B (2), two natural stereoisomers, are isolated from Teucrium yemense (Defl). These two compounds are almost identical to each other, differing only at the C6 stereocenter. We now crystallise these two compounds and for the first time, determine the crystal structure through single crystal X-ray diffraction, and the stereochemistry for all positions using spectroscopic data. These techniques enable us to establish the difference between the two compounds. Careful interpretation of the results indicates that HRMS and 1 and 2D NMR spectroscopy, are in agreement with single crystal X-ray diffraction data.

An x-ray diffraction study of some mesoionic 2,3-diphenyltetrazoles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luboradzki, R.; Kozminski, W.; Stefaniak, L.

1993-02-01

An X-my diffraction study is reported for four molecules of mesoionic 2,3-diphenyltetrazoles. The results confirm a dipolar [open quotes]mesoionic[close quotes] structure, aromatic character of the tetrazole ring and no conjugation between the phenyl and tetrazole rings. The geometry of the exocyclic group is discussed in detail. The molecular parameters of the compounds investigated are correlated with [sup 13]C and [sup 15]N nmr data. The results obtained are compared with similar structures which have already been studied.

NMR and X-ray studies of isomeric 22,23-dihydroxy stigmastanes

NASA Astrophysics Data System (ADS)

Khripach, Vladimir A.; Zhabinskii, Vladimir N.; Ivanova, Galina V.; Fando, Galina P.; Tsavlovskii, Dmitrii V.; Khripach, Natalya B.; Lyakhov, Alexander S.; Misharin, Alexander Yu.

2010-06-01

A comparative conformational study of steroidal side chain of (22 R,23 R)- and (22 S,23 S)-dihydroxy stigmastane derivatives was performed using single crystal X-ray diffraction and NMR spectroscopy. The preferred conformation in solution was shown to be close to that in the crystal. (22 R,23 R)-Isomers typical for natural plant steroid hormones brassinosteroids adopt a conformation in which both hydroxyl groups are pointed toward unhindered α-side of the steroidal plane and can thus participate in biochemical processes. Unnatural (22 S,23 S)-counterparts exhibit a conformation with the two hydroxyl groups oriented in the opposite direction and sterically hindered by 21-methyl group and terminal side chain fragment.

Synthesis, Characterization, Crystal Structure, and Biological Studies of a Cadmium(II) Complex with a Tridentate Ligand 4′-Chloro-2,2′:6′,2′′-Terpyridine

PubMed Central

Saghatforoush, L. A.; Valencia, L.; Chalabian, F.; Ghammamy, Sh.

2011-01-01

A new Cd(II) complex with the ligand 4′-chloro-2,2′6′,2′′-terpyridine (Cltpy), [Cd(Cltpy)(I)2], has been synthesized and characterized by CHN elemental analysis, 1H-NMR, 13C-NMR, and IR spectroscopy and structurally analyzed by X-ray single-crystal diffraction. The single-crystal X-ray analyses show that the coordination number in complex is five with three terpyridine (Cltpy) N-donor atoms and two iodine atoms. The antibacterial activities of Cltpy and its Cd(II) complex are tested against different bacteria. PMID:21738495

Crystal structure, spectral property, antimicrobial activity and DFT calculation of N-(coumarin-3-yl)-N‧-(2-amino-5-phenyl-1,3,4-thiadiazol-2-yl) urea

NASA Astrophysics Data System (ADS)

Zhang, Hong-Song; Zhang, Kong-Yan; Chen, Li-Chuan; Li, Yao-Xin; Chai, Lan-Qin

2017-10-01

N-(coumarin-3-yl)-N‧-(2-amino-5-phenyl-1,3,4-thiadiazol-2-yl) urea was synthesized and characterized by elemental analysis, IR, 1H NMR, 13C NMR, UV-Vis and emission spectroscopy, as well as by single-crystal X-ray diffraction. X-ray crystallographic analyses have indicated that the crystal structure consists of two dimethyl sulfoxide (DMSO) solvent molecules and the structural geometry of DMSO is a trigonal pyramid in shape. In the crystal structure, a self-assembling two-dimensional (2-D) layer supramolecular architecture is formed through intermolecular hydrogen bonds, Cdbnd O···π (thiadiazole ring) and π···π stacking interactions. The geometry of the compound has been optimized by the DFT method and the results are compared with the X-ray diffraction data. The electronic transitions and spectral features of the compound were carried out by using DFT/B3LYP method. In addition, the antimicrobial activity was also studied, and the highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), and HOMO-LUMO gap were also calculated.

Molecular structure of hybrid imino-chalcone in the solid state: X-ray diffraction, spectroscopy study and third-order nonlinear optical properties

NASA Astrophysics Data System (ADS)

Custodio, J. M. F.; Santos, F. G.; Vaz, W. F.; Cunha, C. E. P.; Silveira, R. G.; Anjos, M. M.; Campos, C. E. M.; Oliveira, G. R.; Martins, F. T.; da Silva, C. C.; Valverde, C.; Baseia, B.; Napolitano, H. B.

2018-04-01

A comprehensive structural study of the compound (2E)-1-((E)-4-(4-methoxybenzylideneamino)phenyl)-3-(4-methoxyphenyl)prop-2-en-1-one was carried out in this work. Single crystal X-ray diffraction (SCXRD), X-ray powder diffraction (XRPD), NMR, Raman and Infrared spectroscopies, and DFT calculations were performed for characterization of this iminochalcone hybrid. Intermolecular interactions were described by Hirshfeld surface analysis derived from crystal structure. Reactivity and intramolecular charge transfer were investigated using the frontier molecular orbitals and molecular electrostatic potential. In addition, we have calculated the Nonlinear Optical Properties at the CAM-B3LYP/6-311+g(d) level of theory in the presence of different solvents (gas-phase, acetone, chloroform, dichloromethane, dimethyl sulfoxide, ethanol, methanol, and water), being found meaningful NLO parameters for our compound. At last, there is a good agreement between calculated and experimental IR spectrum, allowing the assignment of some of normal vibrational modes of the iminochalcone hybrid.

Synthesis, crystal structure, and spectral studies of 10-(2-Benzothiazolylazo)-9-phenanthrol

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davydov, V. V.; Sokol, V. I.; Polyanskaya, N. A.

2012-03-15

10-(2-Benzothiazolylazo)-9-phenanthrol (L) is prepared by a reaction of 2-hydrazinobenzothiazol with 9,10-phenanthrenequinone. The crystal and molecular structure of the L{center_dot}CHCl{sub 3} solvate is determined by X-ray diffraction. The data of the X-ray diffraction study, as well as IR, {sup 1}H NMR, and electronic absorption spectra, indicate that in the crystal state and solutions the L molecule exists in the form of a quinohydrazone tautomer (b) (s-trans, cis) stabilized by the intramolecular N{sub 2}-HN{sub 2} Horizontal-Ellipsis O1 hydrogen bond. The 'mobile' H atom is located at the N2 atom of the azo group. The benzothiazolyl and phenanthrenequinone fragments are nearly coplanar. Spectroscopicmore » criteria for the state of L in various media are determined based on the data of IR, {sup 1}H NMR, and electronic absorption spectroscopy and the results of the Pariser-Parr-Pople quantum-chemical calculations.« less

Hirshfeld surface analyses and crystal structures of supramolecular self-assembly thiourea derivatives directed by non-covalent interactions

NASA Astrophysics Data System (ADS)

Gumus, Ilkay; Solmaz, Ummuhan; Binzet, Gun; Keskin, Ebru; Arslan, Birdal; Arslan, Hakan

2018-04-01

The novel N-(bis(3,5-dimethoxybenzyl)carbamothioyl)-4-R-benzamide (R: H, Cl, CH3 and OCH3) compounds have been synthesized and characterized by FT-IR, 1H NMR and 13C NMR spectroscopy. Their crystal structures were also determined by single-crystal X-ray diffraction studies. Hirshfeld surfaces analysis and their associated two dimensional fingerprint plots of compounds were used as theoretical approach to assess driving force for crystal structure formation via the intermolecular interactions in the crystal lattices of synthesized compounds. The study of X-ray single crystal diffraction and Hirshfeld surfaces analysis of the prepared compounds shows that hydrogen bonding and other weaker interactions such as Nsbnd H⋯S, weak Csbnd H⋯S, Csbnd H⋯O, Csbnd H⋯N and Csbnd H···π intermolecular interactions and π-π stacking, among molecules of synthesized compounds participate in a cooperative way to stabilize the supramolecular structures.

Racemic crystals of trolox derivatives compared to their chiral counterparts: Structural studies using solid-state NMR, DFT calculations and X-ray diffraction

NASA Astrophysics Data System (ADS)

Wałejko, P.; Paradowska, K.; Szeleszczuk, Ł.; Wojtulewski, S.; Baj, A.

2018-03-01

Trolox C (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) is a water-soluble vitamin E analogue that is available in enantiomeric forms R or S. Enantiomerically pure Trolox 1, its derivatives 2, 3 (R and S enantiomers) and racemic forms 1-3 were studied using solid-state 13C cross-polarisation (CP) magic angle spinning (MAS) NMR (13C CPMAS NMR). Gauge-including projector-augmented wave density functional theory (GIPAW DFT) calculations of the shielding constants supported the assignment of 13C resonances in the solid-state NMR spectra. For the 13C CPMAS NMR spectra of 1, resonances of pure enantiomers were significantly broader than those of the racemic R/S form. In order to explain these effects, five of the available crystal structures were analysed (1R/S, 3R/S, 2S and the newly measured 2R/S and 3S). Cyclic dimers with one R and one S enantiomer linked by two OHsbnd Odbnd C2b hydrogen bonds were formed in 1R/S. Similar hydrogen-bonded dimers were present in 3S but not in 3R/S, in which interactions are water-mediated. A comparison of X-ray diffraction, CPMAS NMR data and the DFT GIPAW calculations of racemic forms and pure enantiomers was conducted for the first time. Our results, particularly the solid-state NMR data, were discussed in relation to Wallach's rule, that the racemic crystal appears as more ordered than its chiral counterpart.

Synthesis and characterization of 3-acetoxy-2-methyl-N-(phenyl)benzamide and 3-acetoxy-2-methyl-N-(4- methylphenyl)benzamide

NASA Astrophysics Data System (ADS)

Kırca, Başak Koşar; Çakmak, Şükriye; Kütük, Halil; Odabaşoğlu, Mustafa; Büyükgüngör, Orhan

2018-01-01

This study treats about two successfully synthesized secondary amide compounds 3-Acetoxy-2-methyl-N-(phenyl)benzamide, I and 3-Acetoxy-2-methyl-N-(4-methylphenyl)benzamide, II. Compounds were characterized by FTIR, 1H NMR, 13C NMR and X-ray single crystal diffraction analysis techniques. Single crystal X-ray diffraction analyses show that while I crystallized in the orthorhombic system with space group Pbca, II crystallized in the triclinic system with space group P-1 and the asymmetric unit of II consists of two crystallographically independent molecules. Lattice constants are a = 7.9713 (3) Å, b = 9.5059 (3) Å, c = 37.1762 (2) Å, Z = 8 for I and a = 7.5579 (8) Å, b = 8.8601 (8) Å, c = 23.363 (3) Å, α = 97.011 (9) °, β = 96.932 (9)°, γ = 90.051 (8)°, Z = 4 for II. Crystallographic studies also show that the supramolecular structures were stabilized by intramolecular, intermolecular hydrogen bonds and Csbnd H … π interactions for both compounds. Characteristic amide bonds were observed in IR and NMR spectra.

Structural, antimicrobial and computational characterization of 1-benzoyl-3-(5-chloro-2-hydroxyphenyl)thiourea.

PubMed

Atiş, Murat; Karipcin, Fatma; Sarıboğa, Bahtiyar; Taş, Murat; Çelik, Hasan

2012-12-01

A new thiourea derivative, 1-benzoyl-3-(5-chloro-2-hydroxyphenyl)thiourea (bcht) has been synthesized from the reaction of 2-amino-4-chlorophenol with benzoyl isothiocyanate. The title compound has been characterized by elemental analyses, FT-IR, (13)C, (1)H NMR spectroscopy and the single crystal X-ray diffraction analysis. The structure of bcht derived from X-ray diffraction of a single crystal has been presented. The structural and spectroscopic data of the molecule in the ground state were calculated by using density functional method using 6-311++G(d,p) basis set. The complete assignments of all vibrational modes were performed on the basis of the total energy distributions (TED). Isotropic chemical shifts ((13)C NMR and (1)H NMR) were calculated using the gauge-invariant atomic orbital (GIAO) method. Theoretical calculations of bond parameters, harmonic vibration frequencies and nuclear magnetic resonance are in good agreement with experimental results. The UV absorption spectra of the compound that dissolved in ACN and MeOH were recorded. Bcht was also screened for antimicrobial activity against pathogenic bacteria and fungi. Copyright © 2012 Elsevier B.V. All rights reserved.

Dissociation behavior of methane--ethane mixed gas hydrate coexisting structures I and II.

PubMed

Kida, Masato; Jin, Yusuke; Takahashi, Nobuo; Nagao, Jiro; Narita, Hideo

2010-09-09

Dissociation behavior of methane-ethane mixed gas hydrate coexisting structures I and II at constant temperatures less than 223 K was studied with use of powder X-ray diffraction and solid-state (13)C NMR techniques. The diffraction patterns at temperatures less than 203 K showed both structures I and II simultaneously convert to Ih during the dissociation, but the diffraction pattern at temperatures greater than 208 K showed different dissociation behavior between structures I and II. Although the diffraction peaks from structure II decreased during measurement at constant temperatures greater than 208 K, those from structure I increased at the initial step of dissociation and then disappeared. This anomalous behavior of the methane-ethane mixed gas hydrate coexisting structures I and II was examined by using the (13)C NMR technique. The (13)C NMR spectra revealed that the anomalous behavior results from the formation of ethane-rich structure I. The structure I hydrate formation was associated with the dissociation rate of the initial methane-ethane mixed gas hydrate.

Testing the limits of sensitivity in a solid-state structural investigation by combined X-ray powder diffraction, solid-state NMR, and molecular modelling.

PubMed

Filip, Xenia; Borodi, Gheorghe; Filip, Claudiu

2011-10-28

A solid state structural investigation of ethoxzolamide is performed on microcrystalline powder by using a multi-technique approach that combines X-ray powder diffraction (XRPD) data analysis based on direct space methods with information from (13)C((15)N) solid-state Nuclear Magnetic Resonance (SS-NMR) and molecular modeling. Quantum chemical computations of the crystal were employed for geometry optimization and chemical shift calculations based on the Gauge Including Projector Augmented-Wave (GIPAW) method, whereas a systematic search in the conformational space was performed on the isolated molecule using a molecular mechanics (MM) approach. The applied methodology proved useful for: (i) removing ambiguities in the XRPD crystal structure determination process and further refining the derived structure solutions, and (ii) getting important insights into the relationship between the complex network of non-covalent interactions and the induced supra-molecular architectures/crystal packing patterns. It was found that ethoxzolamide provides an ideal case study for testing the accuracy with which this methodology allows to distinguish between various structural features emerging from the analysis of the powder diffraction data. This journal is © the Owner Societies 2011

Structure of nanocrystalline calcium silicate hydrates: insights from X-ray diffraction, synchrotron X-ray absorption and nuclear magnetic resonance.

PubMed

Grangeon, Sylvain; Claret, Francis; Roosz, Cédric; Sato, Tsutomu; Gaboreau, Stéphane; Linard, Yannick

2016-06-01

The structure of nanocrystalline calcium silicate hydrates (C-S-H) having Ca/Si ratios ranging between 0.57 ± 0.05 and 1.47 ± 0.04 was studied using an electron probe micro-analyser, powder X-ray diffraction, 29 Si magic angle spinning NMR, and Fourier-transform infrared and synchrotron X-ray absorption spectroscopies. All samples can be described as nanocrystalline and defective tobermorite. At low Ca/Si ratio, the Si chains are defect free and the Si Q 3 and Q 2 environments account, respectively, for up to 40.2 ± 1.5% and 55.6 ± 3.0% of the total Si, with part of the Q 3 Si being attributable to remnants of the synthesis reactant. As the Ca/Si ratio increases up to 0.87 ± 0.02, the Si Q 3 environment decreases down to 0 and is preferentially replaced by the Q 2 environment, which reaches 87.9 ± 2.0%. At higher ratios, Q 2 decreases down to 32.0 ± 7.6% for Ca/Si = 1.38 ± 0.03 and is replaced by the Q 1 environment, which peaks at 68.1 ± 3.8%. The combination of X-ray diffraction and NMR allowed capturing the depolymerization of Si chains as well as a two-step variation in the layer-to-layer distance. This latter first increases from ∼11.3 Å (for samples having a Ca/Si ratio <∼0.6) up to 12.25 Å at Ca/Si = 0.87 ± 0.02, probably as a result of a weaker layer-to-layer connectivity, and then decreases down to 11 Å when the Ca/Si ratio reaches 1.38 ± 0.03. The decrease in layer-to-layer distance results from the incorporation of interlayer Ca that may form a Ca(OH) 2 -like structure, nanocrystalline and intermixed with C-S-H layers, at high Ca/Si ratios.

Solid state structural investigations of the bis(chalcone) compound with single crystal X-ray crystallography, DFT, gamma-ray spectroscopy and chemical spectroscopy methods

NASA Astrophysics Data System (ADS)

Yakalı, Gül; Biçer, Abdullah; Eke, Canel; Cin, Günseli Turgut

2018-04-01

A bis(chalcone), (2E,6E)-2,6-bis((E)-3phenylallidene)cyclohexanone, was characterized by 1H NMR, 13C NMR, FTIR, UV-Vis spectroscopy, gamma-ray spectroscopy and single crystal X- ray structural analysis. The optimized molecular structure of the compound is calculated using DFT/B3LYP with 6-31G (d,p) level. The calculated geometrical parameters are in good agreement with the experimental data obtained from our reported X-ray structure. The powder and single crystal compounds were gama-irradiated using clinical electron linear accelerator and 60Co gamma-ray source, respectively. Spectral studies (1H NMR, 13C NMR, FTIR and UV-Vis) of powder chalcone compound were also investigated before and after irradiation. Depending on the irradiation notable changes were observed in spectral features powder sample. Single crystal X-ray diffraction investigation shows that both unirradiated and irradiated single crystal samples crystallizes in a orthorhombic crystal system in the centrosymmetric space group Pbcn and exhibits an C-H..O intramolecular and intermolecular hydrogen bonds. The crystal packing is stabilised by strong intermolecular bifurcate C-H..O hydrogen bonds and π…π stacking interactions. The asymmetric unit of the title compound contains one-half of a molecule. The other half of the molecule is generated with (1-x,y,-3/2-z) symmetry operator. The molecule is almost planar due to having π conjugated system of chalcones. However, irradiated single crystal compound showed significant changes lattice parameters, crystal volume and density. According to results of gamma-ray spectroscopy, radioactive elements of powder compound which are 123Sb(n,g),124Sb,57Fe(g,p),56Mn, 55Mn(g,n), and 54Mn were determined using photoactivation analysis. However, the most intensive gamma-ray energy signals are 124Sb.

Water Structure and Dynamics in Smectites: X-ray Diffraction and 2 H NMR Spectroscopy of Mg–, Ca–, Sr–, Na–, Cs–, and Pb–Hectorite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reddy, U. Venkateswara; Bowers, Geoffrey M.; Loganathan, Narasimhan

2016-04-06

Variable-temperature X-ray diffraction and 2H NMR spectroscopy of the smectite mineral, hectorite, containing interlayer Na +, K +, Cs +, Mg 2+, Ca 2+, Sr 2+, and Pb 2+ equilibrated at 43% relative humidity (RH) and mixed with 2H 2O to form a paste provide a comprehensive picture of the structural environments and dynamics of interlayer 2H 2O and the relationships of these properties to interlayer hydration state, the hydration energy and polarizability of the cation, temperature, and the formation of ice-1h in the interparticle pores. The variation in basal spacing shown by the XRD data correlates well with themore » 2H NMR behavior, and the XRD data show for the first time in hectorites that crystallization of interparticle ice-1h causes a decrease in the interlayer spacing, likely due to removal of interlayer 2H 2O. The variation of the 2H NMR behavior of all the samples with decreasing temperature reflects decreasing frequencies of motion for the rotation of the 2H 2O molecules around their dipoles, reorientation of the 2H 2O molecules, and exchange of the 2H 2O molecules between interlayer sites coordinated to and not coordinated to the cations.« less

Single-crystal X-ray diffraction and NMR crystallography of a 1:1 cocrystal of dithianon and pyrimethanil.

PubMed

Pöppler, Ann Christin; Corlett, Emily K; Pearce, Harriet; Seymour, Mark P; Reid, Matthew; Montgomery, Mark G; Brown, Steven P

2017-03-01

A single-crystal X-ray diffraction structure of a 1:1 cocrystal of two fungicides, namely dithianon (DI) and pyrimethanil (PM), is reported [systematic name: 5,10-dioxo-5H,10H-naphtho[2,3-b][1,4]dithiine-2,3-dicarbonitrile-4,6-dimethyl-N-phenylpyrimidin-2-amine (1/1), C 14 H 4 N 2 O 2 S 2 ·C 12 H 13 N 2 ]. Following an NMR crystallography approach, experimental solid-state magic angle spinning (MAS) NMR spectra are presented together with GIPAW (gauge-including projector augmented wave) calculations of NMR chemical shieldings. Specifically, experimental 1 H and 13 C chemical shifts are determined from two-dimensional 1 H- 13 C MAS NMR correlation spectra recorded with short and longer contact times so as to probe one-bond C-H connectivities and longer-range C...H proximities, whereas H...H proximities are identified in a 1 H double-quantum (DQ) MAS NMR spectrum. The performing of separate GIPAW calculations for the full periodic crystal structure and for isolated molecules allows the determination of the change in chemical shift upon going from an isolated molecule to the full crystal structure. For the 1 H NMR chemical shifts, changes of 3.6 and 2.0 ppm correspond to intermolecular N-H...O and C-H...O hydrogen bonding, while changes of -2.7 and -1.5 ppm are due to ring current effects associated with C-H...π interactions. Even though there is a close intermolecular S...O distance of 3.10 Å, it is of note that the molecule-to-crystal chemical shifts for the involved sulfur or oxygen nuclei are small.

Increasing dissolution of trospium chloride by co-crystallization with urea

NASA Astrophysics Data System (ADS)

Skořepová, Eliška; Hušák, Michal; Čejka, Jan; Zámostný, Petr; Kratochvíl, Bohumil

2014-08-01

The search for various solid forms of an active pharmaceutical ingredient (API) is an important step in drug development. Our aim was to prepare co-crystals of trospium chloride, an anticholinergic drug used for the treatment of incontinence, and to investigate if they have advantageous properties for drug formulation. Phase identification was done by powder X-ray diffraction and single-crystal X-ray diffraction. The chemical composition was verified by solution NMR and the dissolution rate of the prepared phases was studied by IDR (intrinsic dissolution rate). For further analysis of phase stability and transitions, combined thermal analysis and temperature-resolved X-ray powder diffraction were used. Urea was selected as a co-crystallization partner. Trospium chloride urea (1:1) co-crystal was prepared by a solvent evaporation. From single-crystal data, the co-crystal structure was solved in a space group P21/c and compared to previously published structures of trospium chloride. Intrinsic dissolution rate revealed that the co-crystal dissolves 32% faster than pure API. However, its low thermal and pressure stability makes it a challenging choice for the final drug formulation.

Chalcogen analogues of nicotine lactam studied by NMR, FTIR, DFT and X-ray methods

NASA Astrophysics Data System (ADS)

Jasiewicz, Beata; Malczewska-Jaskóła, Karolina; Kowalczyk, Iwona; Warżajtis, Beata; Rychlewska, Urszula

2014-07-01

The selenoanalogue of nicotine has been synthesized and characterized by spectroscopic and X-ray diffraction methods. The crystals of selenonicotine are isomorphic with the thionicotine homologue and consist of molecules engaged in columnar π⋯π stacking interactions between antiparallely arranged pyridine moieties. These interactions, absent in other crystals containing nicotine fragments, seem to be induced by the presence of a lactam group. The molecular structures in the vacuum of the oxo-, thio- and selenonicotine homologues have been calculated by the DFT method and compared with the available X-ray data. The delocalized structure of thionicotine is stabilized by intramolecular Csbnd H⋯S hydrogen bond, which becomes weaker in the partial zwitterionic resonance structure of selenonicotine in favor of multiple Csbnd H⋯Se intermolecular hydrogen-bonds. The calculated data allow a complete assignment of vibration modes in the solid state FTIR spectra. The 1H and 13C NMR chemical shifts were calculated by the GIAO method with B3LYP/6-311G(3df) level. A comparison between experimental and calculated theoretical results indicates that the density functional B3LYP method provided satisfactory results for predicting FTIR, 1H, 13C NMR spectra properties.

Solid state nuclear magnetic resonance studies of prion peptides and proteins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heller, Jonathan

1997-08-01

High-resolution structural studies using x-ray diffraction and solution nuclear magnetic resonance (NMR) are not feasible for proteins of low volubility and high tendency to aggregate. Solid state NMR (SSNMR) is in principle capable of providing structural information in such systems, however to do this efficiently and accurately, further SSNMR tools must be developed This dissertation describes the development of three new methods and their application to a biological system of interest, the priori protein (PrP).

Static and dynamic stereochemistry of the conformational atropisomers of tetra(o-tolyl)benzene.

PubMed

Lunazzi, Lodovico; Mazzanti, Andrea; Minzoni, Mirko

2005-11-25

[graph: see text] Whereas only one atropisomer of 1,2,4,5-tetra(o-tolyl)benzene was observed by X-ray diffraction in the solid, five conformational atropisomers were detected by low-temperature NMR in solution. Their structures were assigned by a combination of NOE experiments, solvent effect, and ab initio calculations. Variable temperature dynamic NMR and bidimensional EXSY experiments allowed the barrier for the interconversion of these atropisomers to be determined (deltaG(double dagger) = 15.3 kcal mol(-1)).

Actinide Corroles: Synthesis and Characterization of Thorium(IV) and Uranium(IV) bis(-chloride) Dimers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ward, Ashleigh L.; Buckley, Heather L.; Gryko, Daniel T.

2013-12-01

The first synthesis and structural characterization of actinide corroles is presented. Thorium(IV) and uranium(IV) macrocycles of Mes2(p-OMePh)corrole were synthesised and characterized by single-crystal X-ray diffraction, UV-Visible spectroscopy, variable-temperature 1H NMR, ESI mass spectrometry and cyclic voltammetry.

Imidazolium tagged acridines: Synthesis, characterization and applications in DNA binding and anti-microbial activities

NASA Astrophysics Data System (ADS)

Raju, Gembali; Vishwanath, S.; Prasad, Archana; Patel, Basant K.; Prabusankar, Ganesan

2016-03-01

New water soluble 4,5-bis imidazolium tagged acridines have been synthesized and structurally characterized by multinuclear NMR and single crystal X-ray diffraction techniques. The DNA binding and anti-microbial activities of these acridine derivatives were investigated by fluorescence and far-UV circular dichroism studies.

[Study on chemical compositions and crystallinity changes of bamboo treated with gamma rays].

PubMed

Sun, Feng-Bo; Jiang, Ze-hui; Fei, Ben-hua; Lu, Fang; Yu, Zi-xuan; Chang, Xiang-zhen

2011-07-01

The structures and qualities of main chemical compositions in cell wall of bamboo treated with gamma rays were tested by nuclear magnetic resonance spectrometer (NMR) and X-ray Diffraction (XRD). The result indicated that the bamboo crystallinity increased at the beginning of irradiation process, while the crystallinity reduced when the irradiation dose was raised to about 100 kGy. During the whole irradiation process, hemicellulose degraded, and with the irradiation doses increased the non-phenolic lignin changed to the phenolic.

Synthesis, structural, conformational and pharmacological study of some amides derived from 3 -methyl-2,4-diphenyl-3-azabicyclo[3.3.1]nonan-9α-amine

NASA Astrophysics Data System (ADS)

Iriepa, I.; Bellanato, J.; Gálvez, E.; Gil-Alberdi, B.

2010-07-01

Some mono-substituted amides ( 2- 5) derived from 3-methyl-2,4-diphenyl-3-azabicyclo[3.3.1]nonan-9α-amine were synthesized and studied by IR, 1H and 13C NMR spectroscopy. The crystal structure of 3-methyl-2,4-diphenyl-9α-(3,5-dichlorobenzamido)-3-azabicyclo[3.3.1]nonane ( 3) was determined by X-ray diffraction. NMR data showed that all compounds adopt in CDCl 3 a preferred flattened chair-chair conformation with the N-CH 3 group in equatorial disposition. X-ray data agreed with this conformation in the case of compound 3. IR data revealed that compounds 2 and 3 present a C dbnd O⋯HN intermolecular bond in the solid state. This conclusion was also confirmed by X-ray data of compound 3. In the case of compound 5, IR results suggested intermolecular NH⋯N-heterocyclic bonding. On the contrary, in the pyrazine derivative ( 4), IR, 1H and 13C NMR data showed the presence of an intramolecular NH⋯N1″-heterocyclic hydrogen bond in the solid state and solution. Moreover, NMR and IR data showed a preferred trans disposition for the NH-C dbnd O group. NMR also revealed free rotation of the -NH-CO-R group around C9-NH bond. Pharmacological assays on mice were drawn to evaluate analgesic activity.

Syntheses, characterisation and crystal structures of ferrocenyl β-diketones and their Schiff base Nsbnd Nsbnd O ligand derivatives with 2-picolylamine

NASA Astrophysics Data System (ADS)

Artigas, Vania; González, Deborah; Fuentealba, Mauricio

2017-02-01

Ferrocenyl β-diketones compounds β3-4 were synthesised by Claisen condensation reaction between acetylferrocene and ethyl benzoate or 4-bromoethyl benzoate. We also synthesised four new Schiff base ligands L1-4 by condensation reaction between β1-4 and 2-picolylamine. Identities of all these compounds were confirmed by satisfactory elemental analysis, 1H nuclear magnetic resonance (NMR) correlation and infrared (IR) spectroscopy. In addition, all these compounds were authenticated by a single-crystal X-ray diffraction analysis. In solution, 1H NMR spectra of β3 and β4 exhibit a mixture of keto:enol tautomer ratios of 12:88 and 8:92, respectively, calculated by the integration of the free cyclopentadienyl ring. In contrast, the proton NMR spectra of L1-4 showed only the keto-enamine tautomer displacements. In addition, decoupled 13C NMR spectrum clearly confirmed the existence of these tautomers. These results are in accordance with X-ray crystallographic studies, in which the enol and keto-enamine forms were elucidated for β-diketones and Schiff base ligands, respectively.

New supramolecular cocrystal of 2-amino-5-chloropyridine with 3-methylbenzoic acids: Syntheses, structural characterization, Hirshfeld surfaces and quantum chemical investigations

NASA Astrophysics Data System (ADS)

Thanigaimani, Kaliyaperumal; Khalib, Nuridayanti Che; Temel, Ersin; Arshad, Suhana; Razak, Ibrahim Abdul

2015-11-01

2-amino-5-chloropyridine: 3-methylbenzoic acid [(2A5CP) (3MBA)] (I) cocrystal was synthesized and its single crystal was grown by slow evaporation technique. The structure of the grown crystal was elucidated by using single crystal X-ray diffraction technique. The cocrystal belongs to the monoclinic crystallographic system with space group P21/c, Z = 4, and a = 13.3155 (5) Å, b = 5.5980 (2) Å, c = 18.3787 (7) Å, β = 110.045 (2)°. The crystal structure is stabilized by Npyridine-H•••Odbnd C, Cdbnd O-H•••Npyridine and C-H⋯O type hydrogen bonding interactions. The presence of unionized -COOH functional group in the cocrystal was identified both by spectral methods and X-ray structural analysis. The experimental studies obtained by using the methods of single crystal X-ray analysis, powder X-ray diffraction (PXRD) analysis, FTIR, 1H NMR and 13C NMR spectroscopies confirmed the predicted cocrystal. The supramolecular assembly of the cocrystal was analyzed and discussed. The molecular geometry, vibrational frequencies of the compound in the ground state were calculated by using the density functional theory (DFT) method with 6-311++G (d,p) basis set and were compared with the experimental data. Additionally, HOMO-LUMO energy gap, natural bond orbital (NBO) analysis and nonlinear optical (NLO) properties of the compound were performed at B3LYP/6-311++G (d,p) level. Hirshfeld surfaces were used to confirm the existence of inter-molecular interactions in the compound.

Electron paramagnetic resonance, scanning electron microscopy with energy dispersion X-ray spectrometry, X-ray powder diffraction, and NMR characterization of iron-rich fired clays.

PubMed

Presciutti, Federica; Capitani, Donatella; Sgamellotti, Antonio; Brunetti, Brunetto Giovanni; Costantino, Ferdinando; Viel, Stéphane; Segre, Annalaura

2005-12-01

The aim of this study is to clarify the structure of an iron-rich clay and the structural changes involved in the firing process as a preliminary step to get information on ancient ceramic technology. To this purpose, illite-rich clay samples fired at different temperatures were characterized using a multitechnique approach, i.e., by electron paramagnetic resonance, scanning electron microscopy with electron dispersion X-ray spectrometry, X-ray powder diffraction, magic angle spinning and multiple quantum magic angle spinning NMR. During firing, four main reaction processes occur: dehydration, dehydroxylation, structural breakdown, and recrystallization. When the results are combined from all characterization methods, the following conclusions could be obtained. Interlayer H2O is located close to aluminum in octahedral sites and is driven off at temperatures lower than 600 degrees C. Between 600 and 700 degrees C dehydroxylation occurs whereas, between 800 and 900 degrees C, the aluminum in octahedral sites disappears, due to the breakdown of the illite structure, and all iron present is oxidized to Fe3+. In samples fired at 1000 and 1100 degrees C iron clustering was observed as well as large single crystals of iron with the occurrence of ferro- or ferrimagnetic effects. Below 900 degrees C the aluminum in octahedral sites presents a continuous distribution of chemical shift, suggesting the presence of slightly distorted sites. Finally, over the whole temperature range, the presence of at least two tetrahedral aluminum sites was revealed, characterized by different values of the quadrupolar coupling constant.

Synthesis, characterization and crystal structure of (2RS,4R)-2-(2-hydroxy-3-methoxyphenyl)thiazolidine-4-carboxylic acid

NASA Astrophysics Data System (ADS)

Muche, Simon; Müller, Matthias; Hołyńska, Małgorzata

2018-03-01

The condensation reaction of ortho-vanillin and L-cysteine leads to formation of a racemic mixture of (2RS,4R)-2-(2-hydroxy-3-methoxyphenyl)thiazolidine-4-carboxylic acid and not, as reported in the available literature, to a Schiff base. The racemic mixture was fully characterized by 1D and 2D NMR techniques, ESI-MS and X-ray diffraction. Addition of ZnCl2 led to formation of crystals in form of colorless needles, suitable for X-ray diffraction studies. The measured crystals were identified as the diastereomer (2R,4R)-2-(2-hydroxy-3-methoxyphenyl)thiazolidine-4-carboxylic acid 1. The bulk material is racemic. Thiazolidine exists as zwitterion in solid state, as indicated by the crystal structure.

Obtaining aluminas from the thermal decomposition of their different precursors: An {sup 27}Al MAS NMR and X-ray powder diffraction studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chagas, L.H.; De Carvalho, G.S.G.; San Gil, R.A.S.

2014-01-01

Graphical abstract: - Highlights: • We synthesized three precursors of alumina from different methods. • The calcination of the precursors generated several alumina polymorphs. • XRD and NMR were used for structural investigation of the polymorphs. • The synthesis route determines the structural and textural properties of the solids. - Abstract: A commercial sample of Boehmite was used as precursor of alumina polymorphs. For comparison, three other precursors were synthesized from different methods. Particularly, the use of excess of urea promoted a very crystalline form of basic aluminum carbonate. The characteristics of the four precursors were investigated by thermal, vibrationalmore » and X-ray powder diffraction (XRD) analysis. Additionally, the nuclear magnetic resonance, with magic angle spinning ({sup 27}Al MAS NMR), was used to verify the coordination of aluminum cations. Each precursor was calcined at various temperatures generating alumina polymorphs, which were structurally analyzed by XRD and {sup 27}Al MAS NMR. Due to interest in catalysis supports, special attention was given to the γ-Al{sub 2}O{sub 3} phase, which in addition to structural investigation was subjected to textural analysis. The results showed that, from different synthesis procedures and common route of calcination, one can obtain materials with the same composition but with different structural and textural properties, which in turn can significantly influence the performance of a supported catalyst.« less

Distribution of Al atoms in the clathrate-I phase Ba8AlxSi46-x at x = 6.9.

PubMed

Bobnar, Matej; Böhme, Bodo; Wedel, Michael; Burkhardt, Ulrich; Ormeci, Alim; Prots, Yurii; Drathen, Christina; Liang, Ying; Nguyen, Hong Duong; Baitinger, Michael; Grin, Yuri

2015-07-28

The clathrate-I phase Ba8AlxSi46-x has been structurally characterized at the composition x = 6.9 (space group Pm3[combining macron]n, no. 223, a = 10.4645(2) Å). A crystal structure model comprising the distribution of aluminium and silicon atoms in the clathrate framework was established: 5.7 Al atoms and 0.3 Si atoms occupy the crystallographic site 6c, while 1.2 Al atoms and 22.8 Si atoms occupy site 24k. The atomic distribution was established based on a combination of (27)Al and (29)Si NMR experiments, X-ray single-crystal diffraction and wavelength-dispersive X-ray spectroscopy.

Pentadienyl chemistry of the heavy alkaline-earth metals revisited.

PubMed

Reiners, Matthias; Fecker, Ann Christin; Freytag, Matthias; Jones, Peter G; Walter, Marc D

2014-05-14

Open-metallocenes of the heavy alkaline-earth metals [(η(5)-Pdl')2M(thf)n] (M = Ca (1), Sr (2), n = 1; M = Ba (3), n = 2; Pdl' = 2,4-tBu2C5H5) are readily prepared by salt-metathesis between MI2 and KPdl' and characterized by NMR spectroscopy and X-ray diffraction studies.

Use of X-Ray Diffraction, Molecular Simulations, and Spectroscopy to Determine the Molecular Packing in a Polymer-Fullerene Bimolecular Crystal

DTIC Science & Technology

2012-09-05

Richter , M. F. Toney , M. Heeney , I. McCulloch , ACS Nano 2009 , 3 , 780 . [ 19 ] H. W. Spiess , Macromolecules 43 , 5479 . [ 20 ] K...Schmidt-Rohr , H. W. Spiess , Multidimensional Solid-State NMR and Polymers , Academic Press , London 1994 . [ 21 ] C. Yang , J. G. Hu

Microstructure, Porosity and Mechanical Property Relationships of Calcium-Silicate-Hydrate

DTIC Science & Technology

1991-02-15

feasibility of producing S ,,zeolite-cement composites . calcium silicate hydrate (C-S-H) structure, NAS NMR, C3S, pH, zeolites, aluminosilicate hydrate...3 S pH- Composition Plots......................................... 6 X-ray Diffraction...6 The System CaO-A1203-SiO 2 -H2 0................................. 8 pH- Composition Plots......................................... 8 MASNMR

1-Pentyl-3-(4-methoxy-1-naphthoyl)indole and 2-(2-methoxy-phenyl)-1-(1-pentyl-1 H-indol-3-yl)-ethanone: X-ray structures and computational studies

NASA Astrophysics Data System (ADS)

Nycz, Jacek E.; Malecki, Grzegorz; Zawiazalec, Marcin; Pazdziorek, Tadeusz; Skop, Patrycja

2010-12-01

1-Pentyl-3-(4-methoxy-1-naphthoyl)indole (shortly named JWH-081) ( 1) and 2-(2-methoxy-phenyl)-1-(1-pentyl-1 H-indol-3-yl)-ethanone (shortly named JWH-250) ( 2), are examples of cannabinoids which were characterized by FTIR, UV-Vis, multinuclear NMR spectroscopy and single crystal X-ray diffraction method. The geometries of the studied compounds were optimized in singlet states using the density functional theory (DFT) method with B3LYP functional. Electronic spectra were calculated by TDDFT method. In general, the predicted bond lengths and angles are in a good agreement with the values based on the X-ray crystal structure data.

Structure of nanocrystalline calcium silicate hydrates: insights from X-ray diffraction, synchrotron X-ray absorption and nuclear magnetic resonance

PubMed Central

Grangeon, Sylvain; Claret, Francis; Roosz, Cédric; Sato, Tsutomu; Gaboreau, Stéphane; Linard, Yannick

2016-01-01

The structure of nanocrystalline calcium silicate hydrates (C–S–H) having Ca/Si ratios ranging between 0.57 ± 0.05 and 1.47 ± 0.04 was studied using an electron probe micro-analyser, powder X-ray diffraction, 29Si magic angle spinning NMR, and Fourier-transform infrared and synchrotron X-ray absorption spectroscopies. All samples can be described as nanocrystalline and defective tobermorite. At low Ca/Si ratio, the Si chains are defect free and the Si Q 3 and Q 2 environments account, respectively, for up to 40.2 ± 1.5% and 55.6 ± 3.0% of the total Si, with part of the Q 3 Si being attributable to remnants of the synthesis reactant. As the Ca/Si ratio increases up to 0.87 ± 0.02, the Si Q 3 environment decreases down to 0 and is preferentially replaced by the Q 2 environment, which reaches 87.9 ± 2.0%. At higher ratios, Q 2 decreases down to 32.0 ± 7.6% for Ca/Si = 1.38 ± 0.03 and is replaced by the Q 1 environment, which peaks at 68.1 ± 3.8%. The combination of X-ray diffraction and NMR allowed capturing the depolymerization of Si chains as well as a two-step variation in the layer-to-layer distance. This latter first increases from ∼11.3 Å (for samples having a Ca/Si ratio <∼0.6) up to 12.25 Å at Ca/Si = 0.87 ± 0.02, probably as a result of a weaker layer-to-layer connectivity, and then decreases down to 11 Å when the Ca/Si ratio reaches 1.38 ± 0.03. The decrease in layer-to-layer distance results from the incorporation of interlayer Ca that may form a Ca(OH)2-like structure, nanocrystalline and intermixed with C–S–H layers, at high Ca/Si ratios. PMID:27275135

CFA-4 - a fluorinated metal-organic framework with exchangeable interchannel cations.

PubMed

Fritzsche, J; Grzywa, M; Denysenko, D; Bon, V; Senkovska, I; Kaskel, S; Volkmer, D

2017-05-23

The syntheses and crystal structures of the fluorinated linker 1,4-bis(3,5-bis(trifluoromethyl)-1H-pyrazole-4-yl)benzene (H 2 -tfpb; 1) and the novel metal-organic framework family M[CFA-4] (Coordination Framework Augsburg University-4), M[Cu 5 (tfpb) 3 ] (M = Cu(i), K, Cs, Ca(0.5)), are described. The ligand 1 is fully characterized by single crystal X-ray diffraction, photoluminescence-, NMR-, IR spectroscopy, and mass spectrometry. The copper(i)-containing MOF crystallizes in the hexagonal crystal system within the chiral space group P6 3 22 (no. 182) and the unit cell parameters are as follows: a = 23.630(5) Å, c = 41.390(5) Å, V = 20 015(6) Å 3 . M[CFA-4] features a porous 3-D structure constructed from pentanuclear copper(i) secondary building units {Cu(pz) 6 } - (pz = pyrazolate). Cu(I)[CFA-4] is fully characterized by synchrotron single crystal X-ray diffraction, thermogravimetric analysis, variable temperature powder X-ray diffraction, IR spectroscopy, photoluminescence and gas sorption measurements. Moreover, thermal stability and gas sorption properties of K[CFA-4] and Cu(I)[CFA-4] are compared.

Dicoumarol complexes of Cu(II) based on 1,10-phenanthroline: Synthesis, X-ray diffraction studies, thermal behavior and biological evaluation

NASA Astrophysics Data System (ADS)

Dholariya, Hitesh R.; Patel, Ketan S.; Patel, Jiten C.; Patel, Kanuprasad D.

2013-05-01

A series of Cu(II) complexes containing dicoumarol derivatives and 1, 10-phenanthroline have been synthesized. Structural and spectroscopic properties of ligands were studied on the basis of mass spectra, NMR (1H and 13C) spectra, FT-IR spectrophotometry and elemental analysis, while physico-chemical, spectroscopic and thermal properties of mixed ligand complexes have been studied on the basis of infrared spectra, mass spectra, electronic spectra, powder X-ray diffraction, elemental analysis and thermogravimetric analysis. X-ray diffraction study suggested the suitable octahedral geometry for hexa-coordinated state. The kinetic parameters such as order of reaction (n), energy of activation (Ea), entropy (S*), pre-exponential factor (A), enthalpy (H*) and Gibbs free energy (G*) have been calculated using Freeman-Carroll method. Ferric-reducing antioxidant power (FRAP) of all complexes were measured. All the compounds were screened for their antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Streptococcus pyogenes and Bacillus subtilis, while antifungal activity against Candida albicans and Aspergillus niger have been carried out. Also compounds against Mycobacterium tuberculosis shows clear enhancement in the anti-tubercular activity upon copper complexation.

Molecular structure studies of (1S,2S)-2-benzyl-2,3-dihydro-2-(1H-inden-2-yl)-1H-inden-1-ol

PubMed Central

Zhang, Tao; Paluch, Krzysztof; Scalabrino, Gaia; Frankish, Neil; Healy, Anne-Marie; Sheridan, Helen

2015-01-01

The single enantiomer (1S,2S)-2-benzyl-2,3-dihydro-2-(1H-inden-2-yl)-1H-inden-1-ol (2), has recently been synthesized and isolated from its corresponding diastereoisomer (1). The molecular and crystal structures of this novel compound have been fully analyzed. The relative and absolute configurations have been determined by using a combination of analytical tools including X-ray crystallography, X-ray Powder Diffraction (XRPD) analysis and Nuclear Magnetic Resonance (NMR) spectroscopy. PMID:25750458

Spectral studies of 2-pyrazoline derivatives: structural elucidation through single crystal XRD and DFT calculations.

PubMed

Chinnaraja, D; Rajalakshmi, R; Srinivasan, T; Velmurugan, D; Jayabharathi, J

2014-04-24

A series of biologically active N-thiocarbamoyl pyrazoline derivatives have been synthesized using anhydrous potassium carbonate as the catalyst. All the synthesized compounds were characterized by FT-IR, (1)H NMR, (13)C NMR spectral studies, LCMS, CHN Analysis and X-ray diffraction analysis (compound 7). In order to supplement the XRD parameters, molecular modelling was carried out by Gaussian 03W. From the optimized structure, the energy, dipolemoment and HOMO-LUMO energies of all the systems were calculated. Copyright © 2014 Elsevier B.V. All rights reserved.

Synthesis, crystal structure and characterization of a new organic-inorganic hybrid material 4-(ammonium methyl) pipyridinium hexachloro stanate (II) trihydrate

NASA Astrophysics Data System (ADS)

Lassoued, Mohamed Saber; Abdelbaky, Mohammed S. M.; Lassoued, Abdelmajid; Ammar, Salah; Gadri, Abdellatif; Ben Salah, Abdelhamid; García-Granda, Santiago

2018-03-01

The present paper undertakes the study of (C6H16N2) SnCl6·3H2O which is a new hybrid compound. It was prepared and characterized by single crystal X-ray diffraction, X-ray powder, Hirshfeld surface, Spectroscopy measurement, thermal study and photoluminescence properties. The single crystal X-ray diffraction studies revealed that the compound crystallizes in monoclinic Cc space group with cell parameters a = 8.3309(9) Å, b = 22.956(2) Å, c = 9.8381(9) Å, β = 101.334(9) ° and Z = 4. The atomic arrangement shows an alternation of organic and inorganic entities. The cohesion between these entities is performed via Nsbnd H⋯Cl, Nsbnd H⋯O, Osbnd H⋯Cl and Osbnd H⋯O hydrogen bonding to form a three-dimensional network. Hirshfeld surface analysis was used to investigate intermolecular interactions, as well 2D finger plots were conducted to reveal the contribution of these interactions in the crystal structure quantitatively. The X-ray powder is in agreement with the X-ray structure. Scanning electron microscope (SEM) was carried out. Furthermore, the room temperature infrared (IR) spectrum of the title compound was recorded and analyzed on the basis of data found in the literature. Solid state 13C NMR spectrum shows four signals, confirming the solid state structure determined by X-ray diffraction. Besides, the thermal analysis studies were performed, but no phase transition was found in the temperature range between 30 and 450 °C. The optical and PL properties of the compound were investigated in the solid state at room temperature and exhibited three bands at 348 and 401 cm-1 and a strong fluorescence at 480 nm.

Crystal Structure of Two V-shaped Ligands with N-Heterocycles

NASA Astrophysics Data System (ADS)

Wang, Gao-Feng; Sun, Shu-Wen; Zhang, Xiao; Sun, Shu-Gang

2017-12-01

Two V-shaped ligands with N-heterocycles, bis(4-(1 H-imidazol-1-yl) phenyl)methanone ( 1), and bis(4-(1 H-benzo[d]imidazol-1-yl)phenyl)methanone ( 2) have been synthesized and characterized by elemental analyses, IR and 1 H NMR spectroscopy. Crystal structures of 1 and 2 have been determined by X-ray diffraction. The crystal of 1 is monoclinic, sp. gr. P21/ c, Z = 4. The crystal of 2 is orthorhombic, sp. gr. Fdd2, Z = 8. X-ray diffraction analyses show that the V-shaped angles of 1 and 2 are 122.72(15)° and 120.7(4)°, respectively. Intermolecular C-H···O, C-H···N, C-H···π, and π···π interactions link the components into three-dimensional networks in the crystal structures.

NHC carbene supported half-sandwich hydridosilyl complexes of ruthenium: the impact of supporting ligands on Si∙∙∙H interligand interactions.

PubMed

Mai, Van Hung; Kuzmina, Lyudmila G; Churakov, Andrei V; Korobkov, Ilia; Howard, Judith A K; Nikonov, Georgii I

2016-01-07

Reaction of complex [CpRu(pyr)3][PF6] (3) with the NHC carbene IPr (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) results in the NHC complex [Cp(IPr)Ru(pyr)2][PF6] (4), which was studied by NMR specroscopy and X-ray diffraction analysis. Reaction of [Cp(IPr)Ru(pyr)2][PF6] (4) with LiAlH4 leads to the trihydride Cp(IPr)RuH3 (5) characterised by spectroscopic methods. Heating compound 5 with hydrosilanes gives the dihydrido silyl derivatives Cp(IPr)RuH2(SiR3) (6). Systematic X-ray diffraction studies suggest that complexes 6 have stronger interligand Si∙∙∙H interactions than the isolobal phosphine complexes Cp(Pr3P)RuH2(SiR3).

Structural changes of TasA in biofilm formation of Bacillus subtilis.

PubMed

Diehl, Anne; Roske, Yvette; Ball, Linda; Chowdhury, Anup; Hiller, Matthias; Molière, Noel; Kramer, Regina; Stöppler, Daniel; Worth, Catherine L; Schlegel, Brigitte; Leidert, Martina; Cremer, Nils; Erdmann, Natalja; Lopez, Daniel; Stephanowitz, Heike; Krause, Eberhard; van Rossum, Barth-Jan; Schmieder, Peter; Heinemann, Udo; Turgay, Kürşad; Akbey, Ümit; Oschkinat, Hartmut

2018-03-27

Microorganisms form surface-attached communities, termed biofilms, which can serve as protection against host immune reactions or antibiotics. Bacillus subtilis biofilms contain TasA as major proteinaceous component in addition to exopolysaccharides. In stark contrast to the initially unfolded biofilm proteins of other bacteria, TasA is a soluble, stably folded monomer, whose structure we have determined by X-ray crystallography. Subsequently, we characterized in vitro different oligomeric forms of TasA by NMR, EM, X-ray diffraction, and analytical ultracentrifugation (AUC) experiments. However, by magic-angle spinning (MAS) NMR on live biofilms, a swift structural change toward only one of these forms, consisting of homogeneous and protease-resistant, β-sheet-rich fibrils, was observed in vivo. Thereby, we characterize a structural change from a globular state to a fibrillar form in a functional prokaryotic system on the molecular level. Copyright © 2018 the Author(s). Published by PNAS.

Structural changes of TasA in biofilm formation of Bacillus subtilis

PubMed Central

Diehl, Anne; Roske, Yvette; Ball, Linda; Chowdhury, Anup; Hiller, Matthias; Molière, Noel; Kramer, Regina; Stöppler, Daniel; Worth, Catherine L.; Schlegel, Brigitte; Leidert, Martina; Cremer, Nils; Erdmann, Natalja; Lopez, Daniel; Stephanowitz, Heike; Krause, Eberhard; Schmieder, Peter; Akbey, Ümit; Oschkinat, Hartmut

2018-01-01

Microorganisms form surface-attached communities, termed biofilms, which can serve as protection against host immune reactions or antibiotics. Bacillus subtilis biofilms contain TasA as major proteinaceous component in addition to exopolysaccharides. In stark contrast to the initially unfolded biofilm proteins of other bacteria, TasA is a soluble, stably folded monomer, whose structure we have determined by X-ray crystallography. Subsequently, we characterized in vitro different oligomeric forms of TasA by NMR, EM, X-ray diffraction, and analytical ultracentrifugation (AUC) experiments. However, by magic-angle spinning (MAS) NMR on live biofilms, a swift structural change toward only one of these forms, consisting of homogeneous and protease-resistant, β-sheet–rich fibrils, was observed in vivo. Thereby, we characterize a structural change from a globular state to a fibrillar form in a functional prokaryotic system on the molecular level. PMID:29531041

Synthesis and high temperature stability of amorphous Si(B)CN-MWCNT composite nanowires

NASA Astrophysics Data System (ADS)

Bhandavat, Romil; Singh, Gurpreet

2012-02-01

We demonstrate synthesis of a hybrid nanowire structure consisting of an amorphous polymer-derived silicon boron-carbonitride (Si-B-C-N) shell with a multiwalled carbon nanotube core. This was achieved through a novel process involving preparation of a boron-modified liquid polymeric precursor through a reaction of trimethyl borate and polyureasilazane under atmospheric conditions; followed by conversion of polymer to glass-ceramic on carbon nanotube surfaces through controlled heating. Chemical structure of the polymer was studied by liquid-NMR while evolution of various ceramic phases was studied by Raman spectroscopy, solid-NMR, Fourier transform infrared and X-ray photoelectron spectroscopy. Electron microscopy and X-ray diffraction confirms presence of amorphous Si(B)CN coating on individual nanotubes for all specimen processed below 1400 degree C. Thermogravimetric analysis, followed by TEM revealed high temperature stability of the carbon nanotube core in flowing air up to 1300 degree C.

Synthesis, spectroscopy and computational studies of some biologically important hydroxyhaloquinolines and their novel derivatives

NASA Astrophysics Data System (ADS)

Malecki, Grzegorz; Nycz, Jacek E.; Ryrych, Ewa; Ponikiewski, Lukasz; Nowak, Maria; Kusz, Joachim; Pikies, Jerzy

2010-04-01

A series crystalline compounds of methyl and phosphinyl derivatives of 2-methylquinolin-8-ol ( 1a) and related 5,7-dichloro-2-methylquinolin-8-ol ( 1b) were quantitatively prepared and characterized by microanalysis, IR, UV-vis and multinuclear NMR spectroscopy. Five of them have been characterized by single crystal X-ray diffraction method. The known compounds, 8-methoxy-2-methylquinoline ( 2a) and 8-methoxyquinoline ( 2d), were synthesised by a new route. NMR solution spectra at ambient temperature, showed readily diagnostic H-1 and C-13 signals from methyl groups. The geometries of the studied compounds were optimized in singlet states using the density functional theory (DFT) method with B3LYP functional. In general, the predicted bond lengths and angles are in a good agreement with the values based on the X-ray crystal structure data. Electronic spectra were calculated by TDDFT method.

Single-crystal X-ray diffraction and NMR crystallography of a 1:1 cocrystal of di­thia­non and pyrimethanil

PubMed Central

Pöppler, Ann-Christin; Corlett, Emily K.; Pearce, Harriet; Seymour, Mark P.; Reid, Matthew; Montgomery, Mark G.

2017-01-01

A single-crystal X-ray diffraction structure of a 1:1 cocrystal of two fungicides, namely di­thia­non (DI) and pyrimethanil (PM), is reported [systematic name: 5,10-dioxo-5H,10H-naphtho­[2,3-b][1,4]dithiine-2,3-dicarbo­nitrile–4,6-dimethyl-N-phenyl­pyrimidin-2-amine (1/1), C14H4N2O2S2·C12H13N2]. Following an NMR crystallography approach, experimental solid-state magic angle spinning (MAS) NMR spectra are presented together with GIPAW (gauge-including projector augmented wave) calculations of NMR chemical shieldings. Specifically, experimental 1H and 13C chemical shifts are determined from two-dimensional 1H–13C MAS NMR correlation spectra recorded with short and longer contact times so as to probe one-bond C—H connectivities and longer-range C⋯H proximities, whereas H⋯H proximities are identified in a 1H double-quantum (DQ) MAS NMR spectrum. The performing of separate GIPAW calculations for the full periodic crystal structure and for isolated mol­ecules allows the determination of the change in chemical shift upon going from an isolated mol­ecule to the full crystal structure. For the 1H NMR chemical shifts, changes of 3.6 and 2.0 ppm correspond to inter­molecular N—H⋯O and C—H⋯O hydrogen bonding, while changes of −2.7 and −1.5 ppm are due to ring current effects associated with C—H⋯π inter­actions. Even though there is a close inter­molecular S⋯O distance of 3.10 Å, it is of note that the mol­ecule-to-crystal chemical shifts for the involved sulfur or oxygen nuclei are small. PMID:28257008

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andreev, P. V., E-mail: andreev@phys.unn.ru; Somov, N. V.; Kalistratova, O. S.

The newly synthesized triphenylbismuth bis(3-phenylprop-2-enoate) was studied by X-ray diffraction and by IR, UV, and NMR spectroscopy. The crystals are monoclinic, sp. gr. C2/c, Z = 4, a = 13.2820(4) Å, b = 21.3750(2) Å, c = 12.2407(2) Å, β = 119.936(1)°. The coordination polyhedron of the bismuth atom can be described as a distorted pentagonal bipyramid.

The fifth solvatomorph of gallic acid with a supramolecular channel structure: Structural complexity and phase transitions

NASA Astrophysics Data System (ADS)

Thomas, Sajesh P.; Kaur, Ramanpreet; Kaur, Jassjot; Sankolli, Ravish; Nayak, Susanta K.; Guru Row, Tayur N.

2013-01-01

A new solvatomorph of gallic acid was generated using chiral additive technique and characterized by single crystal and powder X-ray diffraction, C-13 NMR, IR spectroscopic techniques and thermal analysis. The supramolecular channels formed by hexameric motifs of gallic acid and solvent molecules contain highly disordered solvent molecules with fractional occupancies.

Structure of high alumina content Al2O3-SiO2 composition glasses.

PubMed

Weber, Richard; Sen, Sabyasachi; Youngman, Randall E; Hart, Robert T; Benmore, Chris J

2008-12-25

The structure of binary aluminosilicate glasses containing 60-67 mol % Al2O3 were investigated using high-resolution 27Al NMR and X-ray and neutron diffraction. The glasses were made by aerodynamic levitation of molten oxides. The 67% alumina composition required a cooling rate of approximately 1600 degrees C s(1-) to form glass from submillimeter sized samples. NMR results show that the glasses contain aluminum in 4-, 5-, and 6-fold coordination in the approximate ratio 4:5:1. The average Al coordination increases from 4.57 to 4.73 as the fraction of octahedral Al increases with alumina content. The diffraction results on the 67% composition are consistent with a disordered Al framework with Al ions in a range of coordination environments that are substantially different from those found in the equilibrium crystalline phases. Analysis of the neutron and X-ray structure factors yields an average bond angle of 125 +/- 4 degrees between an Al ion and the adjoining cation via a bridging oxygen. We propose that the structure of the glass is a "transition state" between the alumina-rich liquid and the equilibrium mullite phase that are dominated by 4- and 6-coordinated aluminum ions, respectively.

Solid-state NMR and IR for the analysis of pharmaceutical solids: polymorphs of fosinopril sodium.

PubMed

Brittain, H G; Morris, K R; Bugay, D E; Thakur, A B; Serajuddin, A T

1993-01-01

The two polymorphic modifications of fosinopril sodium have been characterized as to their differences in melting behaviour, powder X-ray diffraction patterns, Fourier transform infrared spectra (FTIR), and solid-state 31P- and 13C-NMR spectra. The polymorphs were found to be enantiotropically related based upon melting point, heat of fusion, and solution mediated transformation data. Analysis of the solid-state FTIR and 13C-NMR data indicated that the environment of the acetal side chain of fosinopril sodium differed in two polymorphs, and that there might be cis-trans isomerization about the C6-N peptide bond. These conformational differences are postulated as the origin of the observed polymorphism.

Synthesis, spectroscopy, X-ray crystallography, DFT calculations, DNA binding and molecular docking of a propargyl arms containing Schiff base.

PubMed

Balakrishnan, C; Subha, L; Neelakantan, M A; Mariappan, S S

2015-11-05

A propargyl arms containing Schiff base (L) was synthesized by the condensation of 1-[2-hydroxy-4-(prop-2-yn-1-yloxy)phenyl]ethanone with trans-1,2-diaminocyclohexane. The structure of L was characterized by IR, (1)H NMR, (13)C NMR and UV-Vis spectroscopy and by single crystal X-ray diffraction analysis. The UV-Visible spectral behavior of L in different solvents exhibits positive solvatochromism. Density functional calculation of the L in gas phase was performed by using DFT (B3LYP) method with 6-31G basis set. The computed vibrational frequencies and NMR signals of L were compared with the experimental data. Tautomeric stability study inferred that the enolimine is more stable than the ketoamine form. The charge delocalization has been analyzed using natural bond orbital (NBO) analysis. Electronic absorption and emission spectral studies were used to study the binding of L with CT-DNA. The molecular docking was done to identify the interaction of L with A-DNA and B-DNA. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthesis of flexirubin-mediated silver nanoparticles using Chryseobacterium artocarpi CECT 8497 and investigation of its anticancer activity.

PubMed

Venil, Chidambaram Kulandaisamy; Sathishkumar, Palanivel; Malathi, Mahalingam; Usha, Rajamanickam; Jayakumar, Rajarajeswaran; Yusoff, Abdull Rahim Mohd; Ahmad, Wan Azlina

2016-02-01

In this work, the synthesis of silver nanoparticles from a pigment produced by a recently-discovered bacterium, Chryseobacterium artocarpi CECT 8497, was achieved, followed by an investigation of its anticancer properties. The bacterial pigment was identified as flexirubin following NMR ((1)H NMR and (13)C NMR), UV-Vis, and LC-MS analysis. An aqueous silver nitrate solution was treated with isolated flexirubin to produce silver nanoparticles. The synthesised silver nanoparticles were subsequently characterised by UV-Vis spectroscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), X-Ray Diffraction (XRD), and Fourier Transform Infrared (FTIR) Spectroscopy methodologies. Furthermore, the anticancer effects of synthesised silver nanoparticles in a human breast cancer cell line (MCF-7) were evaluated. The tests showed significant cytotoxicity activity of the silver nanoparticles in the cultured cells, with an IC50 value of 36μgmL(-1). This study demonstrates that silver nanoparticles, synthesised from flexirubin from C. artocarpi CECT 8497, may have potential as a novel chemotherapeutic agent. Copyright © 2015 Elsevier B.V. All rights reserved.

Structure, equilibrium and ligand exchange dynamics in the binary and ternary dioxouranium(VI)-ethylenediamine-N,N'-diacetic acid-fluoride system: A potentiometric, NMR and X-ray crystallographic study.

PubMed

Palladino, Giuseppe; Szabó, Zoltán; Fischer, Andreas; Grenthe, Ingmar

2006-11-21

The structure, thermodynamics and kinetics of the binary and ternary uranium(VI)-ethylenediamine-N,N'-diacetate (in the following denoted EDDA) fluoride systems have been studied using potentiometry, 1H, 19F NMR spectroscopy and X-ray diffraction. The UO2(2+)-EDDA system could be studied up to -log[H3O+] = 3.4 where the formation of two binary complexes UO2(EDDA)(aq) and UO2(H3EDDA)3+ were identified, with equilibrium constants logbeta(UO2EDDA) = 11.63 +/- 0.02 and logbeta(UO2H3EDDA3+) = 1.77 +/- 0.04, respectively. In the ternary system the complexes UO2(EDDA)F-, UO2(EDDA)(OH)- and (UO2)2(mu-OH)2(HEDDA)2F2(aq) were identified; the latter through 19F NMR. 1H NMR spectra indicate that the EDDA ligand is chelate bonded in UO2(EDDA)(aq), UO2(EDDA)F- and UO2(EDDA)(OH)- while only one carboxylate group is coordinated in UO2(H3EDDA)3+. The rate and mechanism of the fluoride exchange between UO2(EDDA)F- and free fluoride was studied by 19F NMR spectroscopy. Three reactions contribute to the exchange; (i) site exchange between UO2(EDDA)F- and free fluoride without any net chemical exchange, (ii) replacement of the coordinated fluoride with OH- and (iii) the self dissociation of the coordinated fluoride forming UO2(EDDA)(aq); these reactions seem to follow associative mechanisms. (1)H NMR spectra show that the exchange between the free and chelate bonded EDDA is slow and consists of several steps, protonation/deprotonation and chelate ring opening/ring closure, the mechanism cannot be elucidated from the available data. The structure (UO2)2(EDDA)2(mu-H2EDDA) was determined by single crystal X-ray diffraction and contains two UO2(EDDA) units with tetracoordinated EDDA linked by H2EDDA in the "zwitterion" form, coordinated through a single carboxylate oxygen from each end to the two uranium atoms. The geometry of the complexes indicates that there is no geometric constraint for an associative ligand substitution mechanism.

Crystal growth, structural, thermal and mechanical behavior of l-arginine 4-nitrophenolate 4-nitrophenol dihydrate (LAPP) single crystals.

PubMed

Mahadevan, M; Ramachandran, K; Anandan, P; Arivanandhan, M; Bhagavannarayana, G; Hayakawa, Y

2014-12-10

Single crystals of l-arginine 4-nitrophenolate 4-nitrophenol dihydrate (LAPP) have been grown successfully from the solution of l-arginine and 4-nitrophenol. Slow evaporation of solvent technique was adopted to grow the bulk single crystals. Single crystal X-ray diffraction analysis confirms the grown crystal has monoclinic crystal system with space group of P21. Powder X-ray diffraction analysis shows the good crystalline nature. The crystalline perfection of the grown single crystals was analyzed by HRXRD by employing a multicrystal X-ray diffractometer. The functional groups were identified from proton NMR spectroscopic analysis. Linear and nonlinear optical properties were determined by UV-Vis spectrophotometer and Kurtz powder technique respectively. It is found that the grown crystal has no absorption in the green wavelength region and the SHG efficiency was found to be 2.66 times that of the standard KDP. The Thermal stability of the crystal was found by obtaining TG/DTA curve. The mechanical behavior of the grown crystal has been studied by Vicker's microhardness method. Copyright © 2014 Elsevier B.V. All rights reserved.

Fine refinement of solid state structure of racemic form of phospho-tyrosine employing NMR Crystallography approach.

PubMed

Paluch, Piotr; Pawlak, Tomasz; Oszajca, Marcin; Lasocha, Wieslaw; Potrzebowski, Marek J

2015-02-01

We present step by step facets important in NMR Crystallography strategy employing O-phospho-dl-tyrosine as model sample. The significance of three major techniques being components of this approach: solid state NMR (SS NMR), X-ray diffraction of powdered sample (PXRD) and theoretical calculations (Gauge Invariant Projector Augmented Wave; GIPAW) is discussed. Each experimental technique provides different set of structural constraints. From the PXRD measurement the size of the unit cell, space group and roughly refined molecular structure are established. SS NMR provides information about content of crystallographic asymmetric unit, local geometry, molecular motion in the crystal lattice and hydrogen bonding pattern. GIPAW calculations are employed for validation of quality of elucidation and fine refinement of structure. Crystal and molecular structure of O-phospho-dl-tyrosine solved by NMR Crystallography is deposited at Cambridge Crystallographic Data Center under number CCDC 1005924. Copyright © 2014 Elsevier Inc. All rights reserved.

Structural and {sup 31}P NMR investigation of Bi(MM'){sub 2}PO{sub 6} statistic solid solutions: Deconvolution of lattice constraints and cationic influences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Colmont, Marie; Delevoye, Laurent; Ketatni, El Mostafa

2006-07-15

Two solid solutions BiM{sub x} Mg{sub (2-x)}PO{sub 6} (with M {sup 2+}=Zn or Cd) have been studied through {sup 31}P MAS NMR. The analysis has been performed on the basis of refined crystal structures through X-ray diffraction and neutron diffraction. The BiZn {sub x} Mg{sub (2-x)}PO{sub 6} does not provide direct evidence for sensitive changes in the phosphorus local symmetry. This result is in good agreement with structural data which show nearly unchanged lattices and atomic separations through the Zn{sup 2+} for Mg{sup 2+} substitution. On the other hand, the Cd{sup 2+} for Mg{sup 2+} substitution behaves differently. Indeed, upmore » to five resonances are observed, each corresponding to one of the five first-cationic neighbour distributions, i.e. 4Mg/0Cd, 3Mg/1Cd, 2Mg/2Cd, 1Mg/3Cd and 0Mg/4Cd. Their intensities match rather well the expected weight for each configuration of the statistical Cd{sup 2+}/Mg{sup 2+} mixed occupancy. The match is further improved when one takes into account the influence of the 2nd cationic sphere that is available from high-field NMR data (18.8 T). Finally, the fine examination of the chemical shift for each resonance versus x allows to de-convolute the mean Z/a {sup 2} effective field into two sub-effects: a lattice constraint-only term and a chemical-only term whose effects are directly quantifiable. - Graphical abstract: First (CdMg){sub 4} cationic sphere influence on the {sup 31}P NMR signal in Bi(Cd,Mg){sub 2}PO{sub 6}. Display Omitted.« less

Classical Spin Nematic Transition in LiGa0.95In0.05Cr4O8

NASA Astrophysics Data System (ADS)

Wawrzyńczak, R.; Tanaka, Y.; Yoshida, M.; Okamoto, Y.; Manuel, P.; Casati, N.; Hiroi, Z.; Takigawa, M.; Nilsen, G. J.

2017-08-01

We present the results of a combined 7Li -NMR and diffraction study on LiGa0.95In0.05Cr4O8, a member of the LiGa1 -xInxCr4O8 "breathing" pyrochlore family. Via specific heat and NMR measurements, we find that the complex sequence of first-order transitions observed for LiGaCr4O8 is replaced by a single second-order transition at Tf=11 K . Neutron and x-ray diffraction rule out both structural symmetry lowering and magnetic long-range order as the origin of this transition. Instead, reverse Monte Carlo fitting of the magnetic diffuse scattering indicates that the low-temperature phase may be described as a collinear spin nematic state, characterized by a quadrupolar order parameter. This state also shows signs of short-range order between collinear spin arrangements on tetrahedra, revealed by mapping the reverse Monte Carlo spin configurations onto a three-state color model.

DFT calculations in the assignment of solid-state NMR and crystal structure elucidation of a lanthanum(iii) complex with dithiocarbamate and phenanthroline.

PubMed

Gowda, Vasantha; Laitinen, Risto S; Telkki, Ville-Veikko; Larsson, Anna-Carin; Antzutkin, Oleg N; Lantto, Perttu

2016-12-06

The molecular, crystal, and electronic structures as well as spectroscopic properties of a mononuclear heteroleptic lanthanum(iii) complex with diethyldithiocarbamate and 1,10-phenanthroline ligands (3 : 1) were studied by solid-state 13 C and 15 N cross-polarisation (CP) magic-angle-spinning (MAS) NMR, X-ray diffraction (XRD), and first principles density functional theory (DFT) calculations. A substantially different powder XRD pattern and 13 C and 15 N CP-MAS NMR spectra indicated that the title compound is not isostructural to the previously reported analogous rare earth complexes with the space group P2 1 /n. Both 13 C and 15 N CP-MAS NMR revealed the presence of six structurally different dithiocarbamate groups in the asymmetric unit cell, implying a non-centrosymmetric packing arrangement of molecules. This was supported by single-crystal X-ray crystallography showing that the title compound crystallised in the triclinic space group P1[combining macron]. In addition, the crystal structure also revealed that one of the dithiocarbamate ligands has a conformational disorder. NMR chemical shift calculations employing the periodic gauge including projector augmented wave (GIPAW) approach supported the assignment of the experimental 13 C and 15 N NMR spectra. However, the best correspondences were obtained with the structure where the atomic positions in the X-ray unit cell were optimised at the DFT level. The roles of the scalar and spin-orbit relativistic effects on NMR shielding were investigated using the zeroth-order regular approximation (ZORA) method with the outcome that already the scalar relativistic level qualitatively reproduces the experimental chemical shifts. The electronic properties of the complex were evaluated based on the results of the natural bond orbital (NBO) and topology of the electron density analyses. Overall, we apply a multidisciplinary approach acquiring comprehensive information about the solid-state structure and the metal-ligand bonding of the heteroleptic lanthanum complex.

Three new metabolites from Botrytis cinerea.

PubMed

Wang, Tian-Shan; Zhou, Jin-Yan; Tan, Hong

2008-01-01

Three new metabolites, gamma-abscisolactone (1), botrytisic acids A (3) and B (4) were isolated from the fermentation broth of Botrytis cinerea TB-3-H8. Their structures were elucidated on the basis of MS, IR, UV, and NMR spectroscopic data. Compound 2 was isolated from natural resource for the first time. The structure of 1 was further confirmed by single-crystal X-ray diffraction (CCDC-265897).

Anticancer activity of ferrocenylthiosemicarbazones.

PubMed

Sandra, Cortez-Maya; Elena, Klimova; Marcos, Flores-Alamo; Elena, Martínez-Klimova; Arturo, Ramírez-Ramírez; Teresa, Ramírez Apan; Marcos, Martínez-García

2014-03-01

Aliphatic and aromatic ferrocenylthiosemicarbazones were synthesized. The characterization of the new ferrocenylthiosemicarbazones was done by IR, (1)H-NMR and (13)C-NMR spectroscopy, elemental analysis and X-ray diffraction studies. The biological activity of the obtained compounds was assessed in terms of anticancer activity. Their activity against U251 (human glyoblastoma), PC-3 (human prostatic adenocarcinoma), K562 (human chronic myelogenous leukemia), HCT-15 (human colorectal adenocarcinoma), MCF-7 (human mammary adenocarcinoma) and SKLU-1 (human lung adenocarcinoma) cell lines was studied and compared with cisplatin. All tested compounds showed good activity and the aryl-chloro substituted ferrocenylthiosemicarbazones showed the best anticancer activity.

Synthesis, crystal structure and antitumor activities of water soluble protonated salt of 20(S)-camptothecin

NASA Astrophysics Data System (ADS)

Lu, Wen; Wang, Yong; Wang, Luna; Zhao, Fengyi; Yang, Shilong; Xi, Chengjie; Yang, Yu; Xu, Li; Chi, Xingwei

2018-03-01

A water soluble camptothecin protonated salt has been synthesized; single crystals were grown by slow evaporation solution growth technique at room temperature and characterized by single crystal X-ray diffraction, FT-IR and 1H NMR. The CPT was protonated as (CPT+H+) cations, the cationic protonation occurred on the N position at pyridine group, which fromed a cation-anion compound with perchlorate ion that determined by X-Ray diffraction. Its activities against Hela (cervix), MCF-7 (breast), A549 (lung), HepG2 (liver) and HUVEC (umbilical vein, normal cell) were investigated. The toxicity of the protonated salt was slightly lower than camptothecin. IC50 values of 7.01 μM against HepG-2 cell, 8.61 μM against A549 cell, 17.82 μM against McF-7 cell, all of them are lower than the IC50 values of CPT against these cells except Hela cell.

Conformational dimorphism of isochroman-1-ones in the solid state

NASA Astrophysics Data System (ADS)

Babjaková, Eva; Hanulíková, Barbora; Dastychová, Lenka; Kuřitka, Ivo; Nečas, Marek; Vícha, Robert

2014-12-01

Isochroman-1-one derivatives, which are relatives of coumarins, display a broad spectrum of biological activity; therefore, these derivatives attract the attention of chemists. A series of new isochroman-1-ones were prepared by the reaction of benzyl-derived Grignard reagents with acyl chlorides. All of the prepared compounds were characterized using single-crystal X-ray diffraction as well as FT-IR, NMR and MS techniques. Single crystal X-ray diffraction analysis revealed that the isochromanones can adopt two distinct conformations in the solid state. For one of the compounds, two polymorphs with unique forms crystallized separately under different temperatures. The packing of all of the examined crystals is stabilized via weak intramolecular C-H⋯π and/or C-H⋯O interactions. Although the closed conformer was predominantly found in the actual crystals, the open conformer is thermochemically more stable for all of the examined compounds according to DFT calculations.

Coupling XRD, EXAFS, and 13C NMR to study the effect of the carbon stoichiometry on the local structure of UC(1±x).

PubMed

Carvajal Nuñez, U; Martel, L; Prieur, D; Lopez Honorato, E; Eloirdi, R; Farnan, I; Vitova, T; Somers, J

2013-10-07

A series of uranium carbide samples, prepared by arc melting with a C/U ratio ranging from 0.96 to 1.04, has been studied by X-ray diffraction (XRD), (13)C nuclear magnetic resonance (NMR), and extended X-ray absorption fine structure (EXAFS). XRD determines phase uniqueness and the increase of the lattice parameter versus the carbon content. In contrast, (13)C NMR detects the different carbon environments in the lattice and in this study, clearly identifies the presence of discrete peaks for carbon in the octahedral lattice site in UC and an additional peak associated with excess carbon in hyperstoichiometric samples. Two peaks associated with different levels of carbon deficiency are detected for all hypostoichiometric compositions. More than one carbon environment is always detected by (13)C NMR. This exemplifies the difficulty in obtaining a perfect stoichiometric uranium monocarbide UC(1.00). The (13)C MAS spectra of uranium carbides exhibit the effects resulting from the carbon content on both the broadening of the peaks and on the Knight shift. An abrupt spectral change occurs between hypo- and hyperstoichiometric samples. The results obtained by EXAFS highlight subtle differences between the different stoichiometries, and in the hyperstoichiometric samples, the EXAFS results are consistent with the excess carbon atoms being in the tetrahedral interstitial position.

A new soluble and bioactive polymorph of praziquantel.

PubMed

Zanolla, Debora; Perissutti, Beatrice; Passerini, Nadia; Chierotti, Michele R; Hasa, Dritan; Voinovich, Dario; Gigli, Lara; Demitri, Nicola; Geremia, Silvano; Keiser, Jennifer; Cerreia Vioglio, Paolo; Albertini, Beatrice

2018-06-01

Praziquantel is the only available drug to treat Schistosomiasis. However, its utilization is limited by many drawbacks, including the high therapeutic dose needed, resulting in large tablets and capsules difficult to be swallowed, especially from pediatric patients. In this study, an alternative option to overcome these disadvantages is proposed: to switch to a novel crystalline polymorph of racemic compound praziquantel. The preparation of the crystalline polymorph was realized via a neat grinding process in a vibrational mill. The new phase (Form B) was chemically identical to the starting material (as proved by HPLC, 1 H NMR, and polarimetry), but showed different physical properties (as evaluated by SEM, differential scanning calorimetry, thermogravimetry, ATR-FTIR spectroscopy, X-ray powder diffraction, and solid-state NMR). Furthermore, the crystal structure of the new phase was solved from the powder synchrotron X-ray diffraction pattern, resulting in a monoclinic C2/c cell and validated by DFT-D calculation. Moreover the simulated solid-state NMR 13 C chemical shifts were in excellent agreement with the experimental data. The conversion of original praziquantel into Form B showed to affect positively the water solubility and the intrinsic dissolution rate of praziquantel. Both the in vitro and in vivo activity against Schistosoma mansoni were maintained. Our findings suggest that the new phase, that proved to be physically stable for at least one year, is a promising product for designing a new praziquantel formulation. Copyright © 2018 Elsevier B.V. All rights reserved.

Structural investigation of α-LaZr2F11 by coupling X-ray powder diffraction, 19F solid state NMR and DFT calculations

NASA Astrophysics Data System (ADS)

Martineau, Charlotte; Legein, Christophe; Body, Monique; Péron, Olivier; Boulard, Brigitte; Fayon, Franck

2013-03-01

α-LaZr2F11 has been synthesized by solid state reaction. Its crystal structure has been refined from X-ray powder diffraction data (space group no. 72 Ibam, a=7.785(1) Å, b=10.086(1) Å and c=11.102(1) Å). α-LaZr2F11 contains one La, one Zr and four F inequivalent crystallographic sites. F3 and F4 are shared between one ZrF73- polyhedron and one LaF85- polyhedron, while F1 and F2 bridge two ZrF73- polyhedra. 19F 1D MAS NMR spectra of α-LaZr2F11 are in agreement with the proposed structural model. Assignment of the 19F resonances to the corresponding crystallographic sites has been performed on the basis of both their relative intensities and their correlation patterns in a 19F 2D dipolar-based double-quantum recoupling MAS NMR spectrum. DFT calculations of the 19F chemical shielding tensors have been performed using the GIPAW method implemented in the NMR-CASTEP code, for the experimental structure and two PBE-DFT geometry optimized structures of α-LaZr2F11 (atomic position optimization and full geometry optimization with rescaling of the unit cell volume to the experimental value). Computations were done with and without using a modified La pseudopotential allowing the treatment of the 4f localized empty orbitals of La3+. A relatively nice agreement between the experimental 19F isotropic and anisotropic chemical shifts and the values calculated for the proposed structural model is obtained.

New asymmetric and symmetric 2-((pyridin-4-yl)methylenamino)-3 aminomaleo nitrile and 2,3-bis((pyridin-4-yl)methylenamino)maleonitrile Schiff bases: Synthesis, experimental characterization along with theoretical studies

NASA Astrophysics Data System (ADS)

Zare, Nahid; Zabardasti, Abedien; Dusek, Michal; Eigner, Vaclav

2018-07-01

Two novel Schiff bases 2-((pyridin-4-yl)methelenamino)-3-aminomaleonitrile (L1) and 2,3-bis((pyridin-yl)methylenamino)maleonitrile (L2) were synthesized by the condensation of 2,3-diaminomaleonitrile and 4-pyridine carboxaldehyde using the reflux in absolute methanol. The light yellow crystalline precipitates of L1 were used for single-crystal X-ray crystallography. Two ligans L1 and L2 were characterized by UV-Vis, FT-IR and 1H/13C NMR spectroscopy. Also the FT-IR, 1H NMR and 13C NMR spectra of the compounds were calculated at the B3LYP/6-31 + G(d) level of theory. The Schiff base L1 with unit cell parameters: a = 19.8380(9), b = 4.7221(2), c = 12.9703(6) Å, V = 1215.02(9) Å3, Z = 4 crystallizes in the orthorhombic crystal system with space group Pna21. The crystal structure was solved by charge flipping using single crystal X-ray diffraction data collected at 120 K. For both ligands, the experimentally obtained NMR and IR spectra were a good agreement with their calculated counterparts.

A simple and highly selective 2,2-diferrocenylpropane-based multi-channel ion pair receptor for Pb(2+) and HSO4(-).

PubMed

Wan, Qian; Zhuo, Ji-Bin; Wang, Xiao-Xue; Lin, Cai-Xia; Yuan, Yao-Feng

2015-03-28

A structurally simple, 2,2-diferrocenylpropane-based ion pair receptor 1 was synthesized and characterized by (1)H NMR, (13)C NMR, HRMS, elemental analyses, and single-crystal X-ray diffraction. The ion pair receptor 1 showed excellent selectivity and sensitivity towards Pb(2+) with multi-channel responses: a fluorescence enhancement (more than 42-fold), a notable color change from yellow to red, redox anodic shift (ΔE1/2 = 151 mV), while HSO4(-) promoted fluorescence enhancement when Pb(2+) or Zn(2+) was bonded to the cation binding-site. (1)H NMR titration and density functional theory were performed to reveal the sensing mechanism based on photo-induced electron transfer (PET).

Atomic substitutions in synthetic apatite; Insights from solid-state NMR spectroscopy

NASA Astrophysics Data System (ADS)

Vaughn, John S.

Apatite, Ca5(PO4)3X (where X = F, Cl, or OH), is a unique mineral group capable of atomic substitutions for cations and anions of varied size and charge. Accommodation of differing substituents requires some kind of structural adaptation, e.g. new atomic positions, vacancies, or coupled substitutions. These structural adaptations often give rise to important physicochemical properties relevant to a range of scientific disciplines. Examples include volatile trapping during apatite crystallization, substitution for large radionuclides for long-term storage of nuclear fission waste, substitution for fluoride to improve acid resistivity in dental enamel composed dominantly of hydroxylapatite, and the development of novel biomaterials with enhanced biocompatibility. Despite the importance and ubiquity of atomic substitutions in apatite materials, many of the mechanisms by which these reactions occur are poorly understood. Presence of substituents at dilute concentration and occupancy of disordered atomic positions hinder detection by bulk characterization methods such as X-ray diffraction (XRD) and infrared (IR) spectroscopy. Solid-state nuclear magnetic resonance (NMR) spectroscopy is an isotope-specific structural characterization technique that does not require ordered atomic arrangements, and is therefore well suited to investigate atomic substitutions and structural adaptations in apatite. In the present work, solid-state NMR is utilized to investigate structural adaptations in three different types of apatite materials; a series of near-binary F, Cl apatite, carbonate-hydroxylapatite compositions prepared under various synthesis conditions, and a heat-treated hydroxylapatite enriched in 17O. The results indicate that hydroxyl groups in low-H, near binary F,Cl apatite facilitate solid-solution between F and Cl via column reversals, which result in average hexagonal symmetry despite very dilute OH concentration ( 2 mol percent). In addition, 19F NMR spectra indicate that fluorine occupies a complex distribution of atomic positions, which give rise to complex 19F peak shapes owing to varied F-Ca distance. 13C NMR analysis of carbonate-hydroxylapatite indicates that AB-type carbonate hydroxylapatite can be prepared without the presence of sodium or heat treatment. Isotopic 17O enrichment of hydroxylapatite and 17O NMR analysis reveals distinct signals corresponding to phosphate and hydroxyl oxygens, and heat treatment under vacuum results in loss of hydroxyl signal due to decomposition to tricalcium phosphate, which was observed by powder X-Ray diffraction (PXRD).

Spider Silk: From Protein-Rich Gland Fluids to Diverse Biopolymer Fibers

DTIC Science & Technology

2016-01-06

characterize the protein-rich fluid in the various spider silk producing glands. We have been using a battery of magnetic resonance methods including...solution and solid-state nuclear magnetic resonance (NMR) and micro imaging (MRI) in combination with wide angle and small angle X-ray diffraction...range of magnetic resonance methods. We successfully developed magnetic resonance imaging (MRI) techniques with localized spectroscopy to probe the silk

Mononuclear mercury(II) complexes containing bipyridine derivatives and thiocyanate ligands: Synthesis, characterization, crystal structure determination, and luminescent properties

NASA Astrophysics Data System (ADS)

Amani, Vahid; Alizadeh, Robabeh; Alavije, Hanieh Soleimani; Heydari, Samira Fadaei; Abafat, Marzieh

2017-08-01

A series of mercury(II) complexes, [Hg(Nsbnd N)(SCN)2] (Nsbnd N is 4,4‧-dimethyl-2,2‧-bipyridine in 1, 5,5‧-dimethyl-2,2‧-bipyridine in 2, 6,6‧-dimethyl-2,2‧-bipyridine in 3 and 6-methyl-2,2‧-bipyridine in 4), were prepared from the reactions of Hg(SCN)2 with mentioned ligands in methanol. Suitable crystals of these complexes were obtained for X-ray diffraction measurement by methanol diffusion into a DMSO solution. The four complexes were thoroughly characterized by spectral methods (IR, UV-Vis, 13C{1H}NMR, 1H NMR and luminescence), elemental analysis (CHNS) and single crystal X-ray diffraction. The X-ray structural analysis indicated that in the structures of these complexes, the mercury(II) cation is four-coordinated in a distorted tetrahedral configuration by two S atoms from two thiocyanate anions and two N atoms from one chelating 2,2‧-bipyridine derivative ligand. Also, in these complexes intermolecular interactions, for example Csbnd H⋯N hydrogen bonds (in 1-4), Csbnd H⋯S hydrogen bonds (in 1, 2 and 4), π … π interactions (in 2-4), Hg⋯N interactions (in 2) and S⋯S interactions (in 4), are effective in the stabilization of the crystal structures and the formation of the 3D supramolecular complexes. Furthermore, the luminescence spectra of the title complexes show that the intensity of their emission bands are stronger than the emission bands for the free bipyridine derivative ligands.

Analysis of a nanocrystalline polymer dispersion of ebselen using solid-state NMR, Raman microscopy, and powder X-ray diffraction.

PubMed

Vogt, Frederick G; Williams, Glenn R

2012-07-01

Nanocrystalline drug-polymer dispersions are of significant interest in pharmaceutical delivery. The purpose of this work is to demonstrate the applicability of methods based on two-dimensional (2D) and multinuclear solid-state NMR (SSNMR) to a novel nanocrystalline pharmaceutical dispersion of ebselen with polyvinylpyrrolidone-vinyl acetate (PVP-VA), after initial characterization with other techniques. A nanocrystalline dispersion of ebselen with PVP-VA was prepared and characterized by powder X-ray diffraction (PXRD), confocal Raman microscopy and mapping, and differential scanning calorimetry (DSC), and then subjected to detailed 1D and 2D SSNMR analysis involving ¹H, ¹³C, and ⁷⁷Se isotopes and ¹H spin diffusion. PXRD was used to show that dispersion contains nanocrystalline ebselen in the 35-60 nm size range. Confocal Raman microscopy and spectral mapping were able to detect regions where short-range interactions may occur between ebselen and PVP-VA. Spin diffusion effects were analyzed using 2D SSNMR experiments and are able to directly detect interactions between ebselen and the surrounding PVP-VA. The methods used here, particularly the 2D SSNMR methods based on spin diffusion, provided detailed structural information about a nanocrystalline polymer dispersion of ebselen, and should be useful in other studies of these types of materials.

Synthesis and characterization of high quantum yield and oscillator strength 6-chloro-2-(4-cynophenyl)-4-phenyl quinoline (cl-CN-DPQ) organic phosphor for solid-state lighting.

PubMed

Ghate, Minakshi; Dahule, H K; Thejo Kalyani, N; Dhoble, S J

2018-03-01

A novel blue luminescent 6-chloro-2-(4-cynophenyl) substituted diphenyl quinoline (Cl-CN DPQ) organic phosphor has been synthesized by the acid-catalyzed Friedlander reaction and then characterized to confirm structural, optical and thermal properties. Structural properties of Cl-CN-DPQ were analyzed by Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction technique (XRD) and scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDAX) spectroscopy. FTIR spectra confirmed the presence of different functional groups and bond stretching. 1 H-NMR and 13 C-NMR confirmed the formation of an organic Cl-CN-DPQ compound. X-ray diffraction study provided its crystalline nature. The surface morphology of Cl-CN-DPQ was analyzed by SEM, while EDAX spectroscopy revealed the elemental analysis. Differential thermal analysis (TGA/DTA) disclosed its thermal stability up to 250°C. The optical properties of Cl-CN-DPQ were investigated by UV-vis absorption and photoluminescence (PL) measurements. Cl-CN-DPQ exhibits intense blue emission at 434 nm in a solid-state crystalline powder with CIE co-ordinates (0.157, 0.027), when excited at 373 nm. Cl-CN-DPQ shows remarkable Stokes shift in the range 14800-5100 cm -1 , which is the characteristic feature of intense light emission. A narrow full width at half-maximum (FWHM) value of PL spectra in the range 42-48 nm was observed. Oscillator strength, energy band gap, quantum yield, and fluorescence energy yield were also examined using UV-vis absorption and photoluminescence spectra. These results prove its applications towards developing organic luminescence devices and displays, organic phosphor-based solar cells and displays, organic lasers, chemical sensors and many more. Copyright © 2017 John Wiley & Sons, Ltd.

Sonochemical syntheses of a new nano-sized porous lead(II) coordination polymer as precursor for preparation of lead(II) oxide nanoparticles

NASA Astrophysics Data System (ADS)

Ranjbar, Zohreh Rashidi; Morsali, Ali

2009-11-01

Nano-scale of a new Pb(II) coordination polymer, {[Pb(bpacb)(OAc)]·DMF} n ( 1); bpacbH = 3,5-bis[(4-pyridylamino)carbonyl]benzoic acid], were synthesized by a sonochemical method. The nano-material was characterized by scanning electron microscopy, X-ray powder diffraction (XRD), 1H, 13C NMR, IR spectroscopy and elemental analyses. Crystal structure of compound 1 was determined by X-ray crystallography. Calcination of the nano-sized compound 1 at 700 °C under air atmospheres yields PbO nanoparticles. Thermal stability of nano-sized and single crystalline samples of compound 1 were studied and compared with each other.

Diffraction leveraged modulation of X-ray pulses using MEMS-based X-ray optics

DOEpatents

Lopez, Daniel; Shenoy, Gopal; Wang, Jin; Walko, Donald A.; Jung, Il-Woong; Mukhopadhyay, Deepkishore

2016-08-09

A method and apparatus are provided for implementing Bragg-diffraction leveraged modulation of X-ray pulses using MicroElectroMechanical systems (MEMS) based diffractive optics. An oscillating crystalline MEMS device generates a controllable time-window for diffraction of the incident X-ray radiation. The Bragg-diffraction leveraged modulation of X-ray pulses includes isolating a particular pulse, spatially separating individual pulses, and spreading a single pulse from an X-ray pulse-train.

Investigation of two o-hydroxy Schiff bases in terms of prototropy and radical scavenging activity

NASA Astrophysics Data System (ADS)

Albayrak Kaştaş, Çiğdem; Kaştaş, Gökhan; Güder, Aytaç; Gür, Mahmut; Muğlu, Halit; Büyükgüngör, Orhan

2017-02-01

Two Schiff bases, namely (E)-4,6-dibromo-3-methoxy-2-[(phenylimino)methyl]phenol (1) and (Z)-2,4-dibromo-6-[(4-buthylphenylamino)methylene]-5-methoxycyclohexa-2,4-dienone (2), have been investigated by considering solvent, substituent and temperature dependence of prototropy, and scavenging activities. Experimental (X-ray diffraction, UV-vis and NMR) and computational (DFT) techniques have been used to obtain key data on prototropy and other properties of interest. X-ray and UV-vis results underline the variability in the structural preferences of the compounds with respect to the phase and solvent media conditions. This kind of tautomeric behavior has been elaborated by 1H NMR and 13C NMR experiments performed at room and low temperatures. Radical scavenging properties of two compounds have been probed for their usage potentials as therapeutic agent and ingredient in medicinal and food industries, respectively. For this purpose, three different test methods (DPPH, ABTS•+ and DMPD•+) have been used. It has been found from in vivo and in vitro studies that the compound 2 could be interesting as an active component in pharmaceutical industry or as an additive in food industry when its antiradical activity is considered.

Inclusion compound of vitamin B6 in β-CD. Physico-chemical and structural investigations

NASA Astrophysics Data System (ADS)

Borodi, Gheorghe; Kacso, Irina; Farcaş, Sorin I.; Bratu, Ioan

2009-08-01

Structural and physico-chemical characterization of supramolecular assembly of vitamin B6 with β-cyclodextrin (β-CD) prepared by different methods (kneading, co-precipitation and freeze-drying) has been performed by using several spectroscopic techniques (FTIR, 1H NMR, UV-Vis), powder X-ray diffraction and DSC in order to evidence the inclusion compound formation. An analysis of the chemical shifts observed in the 1H-NMR spectra and of the vibrational frequency shifts led to the tentative conclusion that the vitamin B6 probably enters the cyclodextrin torus when forming the β-CD-vitamin B6 inclusion complex.

Synthesis, spectroscopic characterization, X-ray structure and DFT studies on 2,6-bis(1-benzyl-1H-benzo[d]imidazol-2-yl)pyridine

NASA Astrophysics Data System (ADS)

İnkaya, Ersin; Günnaz, Salih; Özdemir, Namık; Dayan, Osman; Dinçer, Muharrem; Çetinkaya, Bekir

2013-02-01

The title molecule, 2,6-bis(1-benzyl-1H-benzo[d]imidazol-2-yl)pyridine (C33H25N5), was synthesized and characterized by elemental analysis, FT-IR spectroscopy, one- and two-dimensional NMR spectroscopies, and single-crystal X-ray diffraction. In addition, the molecular geometry, vibrational frequencies and gauge-independent atomic orbital (GIAO) 1H and 13C NMR chemical shift values of the title compound in the ground state have been calculated using the density functional theory at the B3LYP/6-311G(d,p) level, and compared with the experimental data. The complete assignments of all vibrational modes were performed by potential energy distributions using VEDA 4 program. The geometrical parameters of the optimized structure are in good agreement with the X-ray crystallographic data, and the theoretical vibrational frequencies and GIAO 1H and 13C NMR chemical shifts show good agreement with experimental values. Besides, molecular electrostatic potential (MEP) distribution, frontier molecular orbitals (FMO) and non-linear optical properties of the title compound were investigated by theoretical calculations at the B3LYP/6-311G(d,p) level. The linear polarizabilities and first hyper polarizabilities of the molecule indicate that the compound is a good candidate of nonlinear optical materials. The thermodynamic properties of the compound at different temperatures were calculated, revealing the correlations between standard heat capacity, standard entropy, standard enthalpy changes and temperatures.

Leucocontextins A-R, lanostane-type triterpenoids from Ganoderma leucocontextum.

PubMed

Zhao, Zhen-Zhu; Chen, He-Ping; Li, Zheng-Hui; Dong, Ze-Jun; Bai, Xue; Zhou, Zhong-Yu; Feng, Tao; Liu, Ji-Kai

2016-03-01

Eighteen new lanostane-type triterpenoids, namely leucocontextins A-R (1-18) were isolated from the fruiting bodies of Ganoderma leucocontextum. Their structures were established by 1D and 2D NMR data in conjunction with HRESIMS/HREIMS, X-ray single crystal diffraction analysis. Compound 18 exhibited weak cytotoxicity against K562 and MCF-7 cell lines with IC50 of 20-30 μM. Copyright © 2015 Elsevier B.V. All rights reserved.

Structural Evolution and Atom Clustering in β-SiAlON: β-Si 6–z Al z O z N 8–z

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cozzan, Clayton; Griffith, Kent J.; Laurita, Geneva

2017-02-06

SiAlON ceramics, solid solutions based on the Si 3N 4 structure, are important, lightweight structural materials with intrinsically high strength, high hardness, and high thermal and chemical stability. Described by the chemical formula β-Si 6–zAl zO zN 8–z, from a compositional viewpoint, these materials can be regarded as solid solutions between Si 3N 4 and Al 3O 3N. A key aspect of the structural evolution with increasing Al and O (z in the formula) is to understand how these elements are distributed on the β-Si 3N 4 framework. The average and local structural evolution of highly phase-pure samples of β-Simore » 6–zAl zO zN 8–z with z = 0.050, 0.075, and 0.125 are studied here, using a combination of X-ray diffraction, NMR studies, and density functional theory calculations. Synchrotron X-ray diffraction establishes sample purity and indicates subtle changes in the average structure with increasing Al content in these compounds. Solid-state magic-angle-spinning 27Al NMR experiments, coupled with detailed ab initio calculations of NMR spectra of Al in different AlO qN 4–q tetrahedra (0 ≤ q ≤ 4), reveal a tendency of Al and O to cluster in these materials. Independently, the calculations suggest an energetic preference for Al–O bond formation, instead of a random distribution, in the β-SiAlON system.« less

Structural Insights into Bound Water in Crystalline Amino Acids: Experimental and Theoretical (17)O NMR.

PubMed

Michaelis, Vladimir K; Keeler, Eric G; Ong, Ta-Chung; Craigen, Kimberley N; Penzel, Susanne; Wren, John E C; Kroeker, Scott; Griffin, Robert G

2015-06-25

We demonstrate here that the (17)O NMR properties of bound water in a series of amino acids and dipeptides can be determined with a combination of nonspinning and magic-angle spinning experiments using a range of magnetic field strengths from 9.4 to 21.1 T. Furthermore, we propose a (17)O chemical shift fingerprint region for bound water molecules in biological solids that is well outside the previously determined ranges for carbonyl, carboxylic, and hydroxyl oxygens, thereby offering the ability to resolve multiple (17)O environments using rapid one-dimensional NMR techniques. Finally, we compare our experimental data against quantum chemical calculations using GIPAW and hybrid-DFT, finding intriguing discrepancies between the electric field gradients calculated from structures determined by X-ray and neutron diffraction.

Novel aldehyde and thiosemicarbazone derivatives: Synthesis, spectroscopic characterization, structural studies and molecular docking studies

NASA Astrophysics Data System (ADS)

Karakurt, Tuncay; Tahtaci, Hakan; Subasi, Nuriye Tuna; Er, Mustafa; Ağar, Erbil

2016-12-01

In this study our purpose is that, synthesis and characterization of compounds containing the aldehyde and thiosemicarbazone groups and comparison of the theoretical results with the experimental results. The structures of all synthesized compounds were elucidated by IR, 1H NMR, 13C NMR, elemental analyses techniques. The structure of compound (4) (C9H8N4O2S) was also elucidated by X-ray diffraction analysis. In addition, the theoretical IR spectrum, 1H NMR and 13C NMR chemical shift values, frontier molecular orbital values (FMO) of these molecules were analyzed by using Becke-3- Lee-Yang-Parr (B3LYP) method with LanL2DZ basis set. Finally, molecular docking studies were performed on synthesized compounds using the 4DKI beta-lactam protein structure to determine the potential binding mode of inhibitors.

Computational NMR, IR/RAMAN calculations in sodium pravastatin: Investigation of the Self-Assembled Nanostructure of Pravastatin-LDH (Layered Double Hydroxides) Systems

NASA Astrophysics Data System (ADS)

Petersen, Philippe; Cunha, Vanessa; Gonçalves, Marcos; Petrilli, Helena; Constantino, Vera; Instituto de Física, Departamento de Física de Materiais e Mecânica Team; Instituto de Química, Departamento de Química Fundamental Team

2013-03-01

Layered double hydroxides (LDH) can be used as nanocontainers for immobilization of Pravastatin, in order to obtain suitable drug carriers. The material's structure and spectroscopic properties were analyzed by NMR, IR/RAMAN and supported by theoretical calculations. Density Functional Theory (DFT) calculations were performed using the Gaussian03 package. The geometry optimizations were performed considering the single crystal X-ray diffraction data of tert-octylamonium salt of Pravastatin. Tetramethylsilane (TMS), obtained with the same basis set, was used as reference for calculating the chemical shift of 13C. A scaling factor was used to compare theoretical and experimental harmonic vibrational frequencies. Through the NMR and IR/RAMAN spectra, we were able to make precise assignments of the NMR and IR/RAMAN of Sodium Pravastatin. We acknowledge support from CAPES, INEO and CNPQ.

Studies on synthesis, growth, structural, thermal, linear and nonlinear optical properties of organic picolinium maleate single crystals.

PubMed

Pandi, P; Peramaiyan, G; Sudhahar, S; Chakkaravarthi, G; Mohan Kumar, R; Bhagavannarayana, G; Jayavel, R

2012-12-01

Picolinium maleate (PM), an organic material has been synthesised and single crystals were grown by slow evaporation technique. The structure of the grown crystal was elucidated by using single crystal X-ray diffraction analysis. PM crystal belongs to the monoclinic crystallographic system with space group P2(1)/c. The crystalline perfection of the grown crystals was analyzed by high-resolution X-ray diffraction rocking curve measurements. The presence of functional groups in PM was identified by FTIR and FT-NMR spectral analyses. Thermal behaviour and stability of picolinium maleate were studied by TGA/DTA analyses. UV-Vis spectral studies reveal that PM crystals are transparent in the wavelength region 327-1100 nm. The laser damage threshold value of PM crystal was found to be 4.3 GW/cm(2) using Nd:YAG laser. The Kurtz and Perry powder second harmonic generation technique confirms the nonlinear optical property of the grown crystal. Copyright © 2012 Elsevier B.V. All rights reserved.

Gas-phase surface esterification of cellulose microfibrils and whiskers.

PubMed

Berlioz, Sophie; Molina-Boisseau, Sonia; Nishiyama, Yoshiharu; Heux, Laurent

2009-08-10

A new and highly efficient synthetic method has been developed for the surface esterification of model cellulosic substrates of high crystallinity and accessibility, namely, freeze-dried tunicin whiskers and bacterial cellulose microfibrils dried by the critical point method. The reaction, which is based on the gas-phase action of palmitoyl chloride, was monitored by solid-state CP-MAS (13)C NMR. It was found that the grafting density not only depended on the experimental conditions, but also on the nature and conditioning of the cellulose samples. The structural and morphological modifications of the substrates at various degrees of grafting were revealed by scanning electron microscopy and X-ray diffraction analysis. These characterizations indicated that the esterification proceeded from the surface of the substrate to their crystalline core. Hence, for moderate degree of substitution, the surface was fully grafted whereas the cellulose core remained unmodified and the original fibrous morphology maintained. An almost total esterification could be achieved under certain conditions, leading to highly substituted cellulose esters, presenting characteristic X-ray diffraction patterns.

Trinuclear organooxotin assemblies from solvothermal synthesis reaction: Crystal structure, hydrogen bonding and π π stacking interaction

NASA Astrophysics Data System (ADS)

Ma, Chunlin; Sun, Junshan; Zhang, Rufen

2007-05-01

Two new trinuclear mono-organooxotin(IV) complexes with 2,3,4,5-tetrafluorobenzoic acid and sodium perchlorate of the types: [(SnR) 3(OH)(2,3,4,5-F 4C 6HCO 2) 4 · ClO 4] · [O 2CC 6HF 4](R = PhCH 2, 1; o- F-PhCH 2 for 2), have been solvothermally synthesized and structurally characterized by elemental, IR, 1H, 13C and 119Sn NMR and X-ray crystallography diffraction analyses. Complex 2 is also characterized by X-ray crystallography diffraction analyses. In complex 2, four carboxyl groups and a perchlorate bridged three tin atoms in a cyclohexane chair arrangement and form the basic framework. A hydroxyl group comprises the oxygen components of the stannoxane ring system. In these complexes, weak but significant intramolecular hydrogen bonding and π-π stacking interaction are also shown. These contacts lead to aggregation and supramolecular assembly of complexes 1 and 2 into 1D or 2D framework.

Synthesis and spectral studies on Cd(II) dithiocarbamate complexes and their use as precursors for CdS nanoparticles

NASA Astrophysics Data System (ADS)

Sathiyaraj, Ethiraj; Padmavathy, Krishnaraj; Kumar, Chandran Udhaya; Krishnan, Kannan Gokula; Ramalingan, Chennan

2017-11-01

Bis(N-cyclopropyl-N-4-chlorobenzyldithiocarbamato-S,S‧)cadmium(II) (1) and (2,2‧-bipyridine) bis(N-cyclopropyl-N-4-chlorobenzyldithiocarbamato-S,S‧)cadmium(II) (2) have been synthesized and characterized by FT-IR, 1HNMR and 13C NMR analyses. For the complex 2, single crystal X-ray diffraction analysis and computational studies (optimized geometry, HOMO-LUMO and MEP) have been executed employing DFT/B3LYP method with LANL 2DZ basic set. The optimized bond lengths and bond angles agree well with the experimental results. The complexes 1 and 2 have been used as single source precursors for the synthesis of ethyleneglycol capped CdS1 and CdS2 nanoparticles, respectively. CdS1 and CdS2 nanoparticles have been synthesized by solvothermal method. PXRD, SEM, Elemental colour mapping, EDAX, TEM and UV-Vis spectroscopy have been used to characterize the as-prepared CdS nanoparticles. The X-ray diffraction pattern confirms both their hexagonal structures.

Electrical conductivity, differential scanning calorimetry, X-ray diffraction, and 7Li nuclear magnetic resonance studies of n-C x H(2 x+1)OSO3Li ( x = 12, 14, 16, 18, and 20)

NASA Astrophysics Data System (ADS)

Hirakawa, Satoru; Morimoto, Yoshiaki; Honda, Hisashi

2015-04-01

Electrical conductivity ( σ), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) measurements of n-C x H (2 x+1) OSO 3Li ( x= 12, 14, 16, 18, and 20) crystals were performed as a function of temperature. In addition, σ, DSC, and XRD observations of n-C x H (2 x+1) OSO 3Na and n-C x H (2 x+1) OSO 3K ( x= 12, 14, 16, 18, and 20) crystals were carried out for comparison. DSC results of the salts revealed several solid-solid phase transitions with large entropy changes (Δ S). For n-C 18 H 37 OSO 3Li and n-C 20 H 41 OSO 3Li salts, each melting point produced a small Δ S mp value compared with the total entropy change in the solid phases (Δ S tr1+Δ S tr2). Additionally, Li + ion diffusion was detected in the highest temperature solid phases. For K salts, larger σ values were detected for potassium alkylsulfates compared with those reported for alkyl carboxylate. 7Li NMR spectra of n-C 18 H 37 OSO 3Li crystals recorded in the low-temperature phase showed large asymmetry parameters, suggesting the Li + ions are localized at asymmetric sites in the crystals.

Molecular structure of actein: 13C CPMAS NMR, IR, X-ray diffraction studies and theoretical DFT-GIAO calculations

NASA Astrophysics Data System (ADS)

Jamróz, Marta K.; Bąk, Joanna; Gliński, Jan A.; Koczorowska, Agnieszka; Wawer, Iwona

2009-09-01

Actein is a prominent triterpene glycoside occurring in Actaea racemosa. The triterpene glycosides are believed to be responsible for the estrogenic activity of an extract prepared from this herb. We determined in the crystal structure of actein by X-ray crystallography to be monoclinic P2(1) chiral space group. Refining the disorder, we determined 70% and 30% of contributions of ( S)- and ( R)-actein, respectively. The IR and Raman spectra suggest that actein forms at least four different types of hydrogen bonds. The 13C NMR spectra of actein were recorded both in solution and solid state. The 13C CPMAS spectrum of actein displays multiplet signals, in agreement with the crystallographic data. The NMR shielding constants were calculated for actein using GIAO approach and a variety of basis sets: 6-31G**, 6-311G**, 6-31+G**, cc-pVDZ, cc-pVDZ-su1 and 6-31G**-su1, as well as IGLO approach combined with the IGLO II basis set. The best results (RMSD of 1.6 ppm and maximum error of 3.4 ppm) were obtained with the 6-31G**-su1 basis set. The calculations of the shielding constants are helpful in the interpretation of the 13C CPMAS NMR spectra of actein and actein's analogues.

5-phosphonato-3,4-dihydropyrimidin-2(1H)-ones: Zinc triflate-catalyzed one-pot multi-component synthesis, X-ray crystal structure and anti-inflammatory activity

NASA Astrophysics Data System (ADS)

Essid, Idris; Lahbib, Karima; Kaminsky, Werner; Ben Nasr, Cherif; Touil, Soufiane

2017-08-01

Herein we report a simple and efficient one-pot three-component synthesis of 5-phosphonato-3,4-dihydropyrimidin-2(1H)-ones, through the zinc triflate-catalyzed Biginelli-type reaction of β-ketophosphonates, aldehydes and urea. The compounds obtained were characterized by various spectroscopic tools including IR, NMR (1H, 31P, 13C) spectroscopy, mass spectrometry and single crystal X-ray diffraction. All the synthesized compounds were screened, for the first time, for anti-inflammatory activity by carrageenan-induced hind paw edema method, using female Wister rats and they showed significant anti-inflammatory activity in some cases higher than the standard indomethacin.

Cation Ordering in Li[NixMnxCo(1-2x)]O2-Layered Cathode Materials: A Nuclear Magnetic Resonance (NMR), Pair Distribution Function, X-ray Absorption Spectroscopy, and Electrochemical Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeng,D.; Cabana, J.; Breger, J.

2007-01-01

Several members of the compositional series Li[NixMnxCo(1-2x)]O2 (0.01 = x = 1/3) were synthesized and characterized. X-ray diffraction results confirm the presence of the layered a-NaFeO2-type structure, while X-ray absorption near-edge spectroscopy experiments verify the presence of Ni2+, Mn4+, and Co3+. Their local environment and short-range ordering were investigated by using a combination of 6Li magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy and neutron pair distribution function (PDF) analysis, associated with reverse Monte Carlo (RMC) calculations. The 6Li MAS NMR spectra of compounds with low Ni/Mn contents (x = 0.10) show several well-resolved resonances, which start to mergemore » when the amount of Ni and Mn increases, finally forming a broad resonance at high Ni/Mn contents. Analysis of the 6Li MAS NMR 6Li[Ni0.02Mn0.02Co0.96]O2 spectrum, is consistent with the formation of Ni2+ and Mn4+ clusters within the transition-metal layers, even at these low-doping levels. The oxidation state of Ni in this high Co content sample strongly depends upon the Li/transition metal ratio of the starting materials. Neutron PDF analysis of the highest Ni/Mn content sample Li[Ni1/3Mn1/3Co1/3]O2 shows a tendency for Ni cations to be close to Mn cations in the first coordination shell; however, the Co3+ ions are randomly distributed. Analysis of the intensity of the 'LiCoO2' resonance, arising from Li surrounded by Co3+ in its first two cation coordination shells, for the whole series provides further evidence for a nonrandom distribution of the transition-metal cations. The presence of the insulator-to-metal transition seen in the electrochemical profiles of these materials upon charging correlates strongly with the concentration of the 'LiCoO2' resonance.« less

Micro X-ray diffraction analysis of thin films using grazing-exit conditions.

PubMed

Noma, T; Iida, A

1998-05-01

An X-ray diffraction technique using a hard X-ray microbeam for thin-film analysis has been developed. To optimize the spatial resolution and the surface sensitivity, the X-ray microbeam strikes the sample surface at a large glancing angle while the diffracted X-ray signal is detected with a small (grazing) exit angle. Kirkpatrick-Baez optics developed at the Photon Factory were used, in combination with a multilayer monochromator, for focusing X-rays. The focused beam size was about 10 x 10 micro m. X-ray diffraction patterns of Pd, Pt and their layered structure were measured. Using a small exit angle, the signal-to-background ratio was improved due to a shallow escape depth. Under the grazing-exit condition, the refraction effect of diffracted X-rays was observed, indicating the possibility of surface sensitivity.

The synthesis and structure of a potential immunosuppressant: N-mycophenoyl malonic acid dimethyl ester

NASA Astrophysics Data System (ADS)

Siebert, Agnieszka; Cholewiński, Grzegorz; Garwolińska, Dorota; Olejnik, Adrian; Rachoń, Janusz; Chojnacki, Jarosław

2018-01-01

The synthesis of a potential immunosuppressant, i.e. dimethyl ester of N-mycophenoyl malonic acid was optimized in the reaction of mycophenolic acid (MPA) with amino malonic dimethyl ester in the presence of propanephosphonic anhydride (T3P) as a coupling reagent. The structural properties of the obtained MPA derivative were investigated by NMR, MS and single crystal X-ray diffraction methods. Theoretical considerations of conformational flexibility based on DFT calculations are presented.

Two new diterpenoid lactones isolated from Andrographis paniculata.

PubMed

Wang, Gui-Yang; Wen, Ting; Liu, Fei-Fei; Tian, Hai-Yan; Chun-Lin, Fan; Huang, Xiao-Jun; Ye, Wen-Cai; Wang, Ying

2017-06-01

In the present study, two new diterpenoid lactones, 3-deoxy-andrographoside (1) and 14-deoxy-15-methoxy-andrographolide (2), were isolated from the aerial parts of Andrographis paniculata. Their structures were elucidated by combination of NMR, MS, and chemical methods. The configurations of 1 and 2 were established based on the analysis of ROESY data and single crystal X-ray diffraction experiment. Copyright © 2017 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

Psiguadials A and B, two novel meroterpenoids with unusual skeletons from the leaves of Psidium guajava.

PubMed

Shao, Meng; Wang, Ying; Liu, Zhong; Zhang, Dong-Mei; Cao, Hui-Hui; Jiang, Ren-Wang; Fan, Chun-Lin; Zhang, Xiao-Qi; Chen, He-Ru; Yao, Xin-Sheng; Ye, Wen-Cai

2010-11-05

Psiguadials A (1) and B (2), two novel sesquiterpenoid-diphenylmethane meroterpenoids with unusual skeletons, along with a pair of known epimers, psidial A (3) and guajadial (4), were isolated from the leaves of Psidium guajava. Their structures with absolute configurations were elucidated by means of NMR, X-ray diffraction, and quantum chemical CD calculation. Compounds 1, 2, and 4 exhibited potent inhibitory effects on the growth of human hepatoma cells.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, S.-W., E-mail: sunsw0819@163.com; Zhang, X., E-mail: zhangx@hit.edu.cn; Wang, G.-F.

A series of 2-arylidenebenzocycloalkanones containing heterocyclic rings 1–8 were prepared and characterized by IR, {sup 1}H NMR and elemental analyses. X-ray diffraction study of 6 reveals that the cyclohexyl ring of the 3,4-dihydronaphthalen-1(2H)-one adopts a chair conformation with a maximum deviation of 0.547(3) Å and makes dihedral angles of 52.24(17)° and 11.23(16)°, respectively, with the benzene plane and the mean plane of the benzimidazole ring.

Proton transfer and hydrogen bonding in the organic solid state: a combined XRD/XPS/ssNMR study of 17 organic acid-base complexes.

PubMed

Stevens, Joanna S; Byard, Stephen J; Seaton, Colin C; Sadiq, Ghazala; Davey, Roger J; Schroeder, Sven L M

2014-01-21

The properties of nitrogen centres acting either as hydrogen-bond or Brønsted acceptors in solid molecular acid-base complexes have been probed by N 1s X-ray photoelectron spectroscopy (XPS) as well as (15)N solid-state nuclear magnetic resonance (ssNMR) spectroscopy and are interpreted with reference to local crystallographic structure information provided by X-ray diffraction (XRD). We have previously shown that the strong chemical shift of the N 1s binding energy associated with the protonation of nitrogen centres unequivocally distinguishes protonated (salt) from hydrogen-bonded (co-crystal) nitrogen species. This result is further supported by significant ssNMR shifts to low frequency, which occur with proton transfer from the acid to the base component. Generally, only minor chemical shifts occur upon co-crystal formation, unless a strong hydrogen bond is formed. CASTEP density functional theory (DFT) calculations of (15)N ssNMR isotropic chemical shifts correlate well with the experimental data, confirming that computational predictions of H-bond strengths and associated ssNMR chemical shifts allow the identification of salt and co-crystal structures (NMR crystallography). The excellent agreement between the conclusions drawn by XPS and the combined CASTEP/ssNMR investigations opens up a reliable avenue for local structure characterization in molecular systems even in the absence of crystal structure information, for example for non-crystalline or amorphous matter. The range of 17 different systems investigated in this study demonstrates the generic nature of this approach, which will be applicable to many other molecular materials in organic, physical, and materials chemistry.

Single crystal X-ray diffraction, spectroscopic and mass spectrometric studies of furanocoumarin peucedanin.

PubMed

Bartnik, Magdalena; Arczewska, Marta; Hoser, Anna A; Mroczek, Tomasz; Kamiński, Daniel M; Głowniak, Kazimierz; Gagoś, Mariusz; Woźniak, Krzysztof

2014-01-01

The structure of peucedanin, isolated from Peucedanum tauricum Bieb. (Apiaceae), has been established using single crystal X-ray diffraction. This furanocoumarin isolated from the light petroleum extract of P. tauricum fruits was characterized by high resolution EI-MS, sATR-FTIR and 2D NMR spectroscopic techniques. The EI-MS showed the typical fragmentation pattern of methoxyfuranocoumarins. Extensive 1D (1H and 13C) as well as 2D NMR data enabled complete assignment of the carbon atoms in the peucedanin molecule. The FTIR data confirms intermolecular hydrogen bonding between peucedanin molecules in polar solvents. Peucedanin crystallises in the R-3 space group from the trigonal system with one molecule in the asymmetric part of the unit cell. The crystal lattice of peucedanin consists of the molecules arranged in separate columns. They are related by two fold screw axes and centres of symmetry. Interestingly, peucedanin columns form two channels per unit cell with a diameter of 7.5angstrom going through the crystal lattice in the Z-direction. These channels are filled with disordered water molecules, which are surrounded by hydrophobic methyl groups and are located exactly at the centres of the channels. The peucedanin molecules are stacked in a single column with the opposite orientation of the neighbouring molecules. These results could be interesting in further application of this molecule, for example in biological tests of its activity.

Powder X-ray diffraction, infrared and 13C NMR spectroscopic studies of the homologous series of some solid-state zinc(II) and sodium(I) n-alkanoates

NASA Astrophysics Data System (ADS)

Nelson, Peter N.; Taylor, Richard A.

2015-03-01

A comparative study of the room temperature molecular packing and lattice structures for the homologous series of zinc(II) and sodium(I) n-alkanoates adduced from Fourier transform infrared and solid-state 13C NMR spectroscopic data in conjunction with X-ray powder diffraction measurements is carried out. For zinc carboxylates, metal-carboxyl bonding is via asymmetric bridging bidentate coordination whilst for the sodium adducts, coordination is via asymmetric chelating bidentate bonding. All compounds are packed in a monoclinic crystal system. Furthermore, the fully extended all-trans hydrocarbon chains are arranged as lamellar bilayers. For zinc compounds, there is bilayer overlap, for long chain adducts (nc > 8) but not for sodium compounds where methyl groups from opposing layers in the lamellar are only closely packed. Additionally, the hydrocarbon chains are extended along the a-axis of the unit cell for zinc compounds whilst for sodium carboxylates they are extended along the c-axis. These packing differences are responsible for different levels of Van der Waals effects in the lattices of these two series of compounds, hence, observed odd-even alternation is different. The significant difference in lattice packing observed for these two series of compounds is proposed to be due to the difference in metal-carboxyl coordination mode, arising from the different electronic structure of the central metal ions.

Synthesis, crystal structure, vibrational spectroscopy and photoluminescence of new hybrid compound containing chlorate anions of stanate (II)

NASA Astrophysics Data System (ADS)

Lassoued, Mohamed Saber; Abdelbaky, Mohammed S. M.; Lassoued, Abdelmajid; Meroño, Rafael Mendoza; Gadri, Abdellatif; Ammar, Salah; Ben Salah, Abdelhamid; García-Granda, Santiago

2017-08-01

The present work aimed at studying a new organic-inorganic bis (4-amino quinolinium) hexachloro stanate (II) dihydrate compound. It was prepared and characterized by single crystal X-ray diffraction, X-ray powder, Hirshfeld surface, Spectroscopy measurement, thermal study and photoluminescence properties. It was found to crystallize in the monoclinic system (P21/c space group) with the following lattice parameters: a = 7.2558(6) Å, b = 13.4876(5) Å, c = 17.2107(13) Å, β = 102.028 (12)°. Its crystal structure was determined and refined down to an R value of 0.06 and a wR value of 0.087. The structure consisted of two different alternating organic-inorganic layers. The crystal packing was stabilized by Nsbnd H⋯Cl and Osbnd H⋯Cl hydrogen bonds and π-π interactions. Hirshfeld surface analysis was used to investigate intermolecular interactions, as well 2D finger plots were conducted to reveal the contribution of these interactions in the crystal structure quantitatively. The X-ray powder is in agreement with the X-ray structure. Scanning electronic microscopy (SEM) was carried out. Furthermore, the room temperature Infra Red (IR) spectrum of the title compound was analyzed on the basis of data found in the literature. Solid state 13C NMR spectrum shows ten signals, confirming the solid state structure determined by X-ray diffraction. Thermal analysis shows two anomalies at 380 and 610 °C. The optical properties of the crystal were studied using optical absorption UV-visible and photoluminescence (PL) spectroscopy, which were investigated at room temperature.

Stepwise Construction of Heterobimetallic Cages by an Extended Molecular Library Approach.

PubMed

Hardy, Matthias; Struch, Niklas; Topić, Filip; Schnakenburg, Gregor; Rissanen, Kari; Lützen, Arne

2018-04-02

Two novel heterobimetallic complexes, a trigonal-bipyramidal and a cubic one, have been synthesized and characterized using the same C 3 -symmetric metalloligand, prepared by a simple subcomponent self-assembly strategy. Adopting the molecular library approach, we chose a mononuclear, preorganized iron(II) complex as the metalloligand capable of self-assembly into a trigonal-bipyramidal or a cubic aggregate upon coordination to cis-protected C 2 -symmetric palladium(II) or unprotected tetravalent palladium(II) ions, respectively. The trigonal-bipyramidal complex was characterized by NMR and UV-vis spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and single-crystal X-ray diffraction. The cubic structure was characterized by NMR and UV-vis spectroscopy and ESI-MS.

Synthesis and reactions of C-phosphanylated thiazol-2-thiones.

PubMed

Begum, I; Schnakenburg, G; Streubel, R

2016-02-21

The facile regioselective synthesis of the P(iii) substituted thiazol-2-thione 2 is presented. Reaction of 2 with hydrogenperoxide-urea, elemental sulfur and selenium resulted in P(v) chalcogenide thiazol-2-thiones 3-5. All compounds were characterized using (31)P, (1)H, (13)C NMR, IR and elemental analyses and, additionally, by the single-crystal X-ray diffraction technique. Oxidative desulfurization of the 5-phosphinoylated thiazol-2-thione 3 using hydrogenperoxide led to the first C-phosphanoyl substituted thiazolium salt (6). Deprotonation of 6 and in situ reaction with the cyclooctadiene rhodium(i) chloride dimer yielded thiazol-2-ylidene rhodium(i) complex 7 which was confirmed by NMR spectroscopy and ESI-MS spectrometry.

Ionic liquid catalyzed one-pot multi-component synthesis, characterization and antibacterial activity of novel chromeno[2,3-d]pyrimidin-8-amine derivatives

NASA Astrophysics Data System (ADS)

Kanakaraju, Sankari; Prasanna, Bethanamudi; Basavoju, Srinivas; Chandramouli, G. V. P.

2012-06-01

An efficient, simple and convenient method for the one-pot multi-component synthesis of novel chromeno[2,3-d]pyrimidin-8-amine derivatives has been accomplished by starting from α-naphthol, aryl aldehydes, malononitrile and NH4Cl. The reaction has been catalyzed by 1-butyl-3-methylimidazolium tetrafluoroborate [bmim]BF4 ionic liquid. The newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR, mass spectra, and elemental analysis. The structure of compound 4a was confirmed by single-crystal X-ray diffraction. All the synthesized compounds were evaluated for their in vitro antibacterial activity.

Sulfonamide-containing PTP 1B inhibitors: Docking studies, synthesis and model validation

NASA Astrophysics Data System (ADS)

Niu, Enli; Gan, Qiang; Chen, Xi; Feng, Changgen

2017-01-01

PTP 1B plays an important role in regulating insulin signaling pathway and is regarded as a valid target for curing diabetes and obesity. In this paper, two novel sulfonamide-containing PTP 1B inhibitors were designed, synthesized in mild condition, and characterized by FT-IR, 1H NMR, 13C NMR and elemental analysis. The single crystal of compounds 7 and 8 were obtained and their structures were determined by X-ray single crystal diffraction analysis. In addition, their inhibitory activity were predicted by genetic algorithm, and carried on in vitro enzyme activity test. Of which compound 8 showed good inhibitory activity, in consistent with docking studies.

Highly oxygenated stigmastane-type steroids from the aerial parts of Vernonia anthelmintica Willd.

PubMed

Hua, Lei; Qi, Wei-Yan; Hussain, Syed Hamid; Gao, Kun; Arfan, Mohammad

2012-06-01

Nine new highly oxygenated stigmastane-type steroids, vernoanthelcin A-I (1-9), and two new stigmastane-type steroidal glycosides, vernoantheloside A and B (10 and 11) were isolated from the aerial parts of Vernonia anthelmintica Willd. The structures of compounds 1-11 were determined on the basis of IR, MS, 1D-NMR, and 2D-NMR, and their absolute configurations were deduced using single-crystal X-ray diffraction and the CD exciton chirality method. Compounds 1, 5, 7, 9 and 10 were tested for their effects on estrogen biosynthesis in human ovarian granulosa-like cells (KGN cells). Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lewis, Randolph

Spider silks have the potential to provide new bio-inspired materials for numerous applications in bioenergetics and products ranging from protective clothing to artificial ligaments and tendons. A number of spider silk genes have been cloned and sequenced by the Lewis laboratory revealing the basis for understanding the key elements of spider silk proteins with respect to their materials performance. In particular, specific amino acid motifs have been identified which have been conserved for over 125 million years in all spiders that use their silk to physically trap prey. The key element in taking the next step toward generating bio-based materialsmore » from spider silks will be to move from the current descriptive data to predictive knowledge. Current efforts are focused on mimicking spider silk through synthetic proteins. In developing synthetic silk fibers, we first need to understand the complete secondary and tertiary structure of natural silk so that we can compare synthetic constructs to the natural material. Being able to compare the structure on a single fiber level is critical to the future of molecular directed mimic development because we can vary mechanical properties by different spinning methods. The new generation of synchrotron x-ray diffraction and neutron beamlines will allow, for the first time, determination of the molecular structure of silk fibers and synthetic mimics. We propose an exciting new collaborative research team working jointly between Argonne National Laboratory, Arizona State U. and the University of Wyoming to address the ?characterization of synthetic and natural spider silk fibers using x-ray and neutron diffraction.? Thus these new methodologies will provide understanding of current fibers and determine changes needed to produce fibers with specific properties. The following specific aims are proposed: ? Synthesize spider silk fibers with molecular structures mimicking that of natural silks. Test the mechanic properties of these materials and compare them to natural silk fibers. ? Develop x-ray and neutron diffraction techniques to better determine the structure in amorphous and semicrystalline biopolymers, such as spider silk fibers. ? Combine mechanical testing and structural x-ray and neutron diffraction data to develop a molecular understanding of the structure-function relationship in spider silk materials. ? Elucidate the role water plays in spider silk fiber formation and structure. Emphasis will be placed on combined neutron and NMR studies. ? Use solid-state Nuclear Magnetic Resonance (NMR) to characterize synthetic and natural spider silk materials that show potential as a biomimetic material or bio-inspired polymer architecture. ? Develop EPSCoR student and postdoctoral training and exposure to national laboratory facilities. ? Further develop scientific outreach and chemical education programs and research.« less

Intermediate- and short-range order in phosphorus-selenium glasses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bytchkov, Aleksei; Hennet, Louis; Price, David L.

2011-04-01

State-of-the-art neutron and x-ray diffraction measurements have been performed to provide a definitive picture of the intermediate- and short-range structures of P{sub x}Se{sub 1-x} glasses spanning two glass regions, x 0.025-0.54 and 0.64-0.84. Liquid P{sub 4}Se{sub 3} and amorphous red P and Se were also measured. Detailed information was obtained about the development with increasing phosphorous concentration of intermediate-range order on the length scale {approx}6 A ring , based on the behavior of the first sharp diffraction peak. Attention is also paid to the feature in the structure factor at 7.5 A ring {sup -1}, identified in earlier numerical simulations,more » provides further evidence of the existence of molecular units. The real-space transforms yield a reliable statistical picture of the changing short-range order as x increases, using the information about types and concentrations of local structural units provided by previous NMR measurements to interpret the trends observed.« less

Automated determination of fibrillar structures by simultaneous model building and fiber diffraction refinement.

PubMed

Potrzebowski, Wojciech; André, Ingemar

2015-07-01

For highly oriented fibrillar molecules, three-dimensional structures can often be determined from X-ray fiber diffraction data. However, because of limited information content, structure determination and validation can be challenging. We demonstrate that automated structure determination of protein fibers can be achieved by guiding the building of macromolecular models with fiber diffraction data. We illustrate the power of our approach by determining the structures of six bacteriophage viruses de novo using fiber diffraction data alone and together with solid-state NMR data. Furthermore, we demonstrate the feasibility of molecular replacement from monomeric and fibrillar templates by solving the structure of a plant virus using homology modeling and protein-protein docking. The generated models explain the experimental data to the same degree as deposited reference structures but with improved structural quality. We also developed a cross-validation method for model selection. The results highlight the power of fiber diffraction data as structural constraints.

Synthesis, spectroscopic characterization, X-ray structure and DFT studies on 2,6-bis(1-benzyl-1H-benzo[d]imidazol-2-yl)pyridine.

PubMed

İnkaya, Ersin; Günnaz, Salih; Özdemir, Namık; Dayan, Osman; Dinçer, Muharrem; Çetinkaya, Bekir

2013-02-15

The title molecule, 2,6-bis(1-benzyl-1H-benzo[d]imidazol-2-yl)pyridine (C(33)H(25)N(5)), was synthesized and characterized by elemental analysis, FT-IR spectroscopy, one- and two-dimensional NMR spectroscopies, and single-crystal X-ray diffraction. In addition, the molecular geometry, vibrational frequencies and gauge-independent atomic orbital (GIAO) (1)H and (13)C NMR chemical shift values of the title compound in the ground state have been calculated using the density functional theory at the B3LYP/6-311G(d,p) level, and compared with the experimental data. The complete assignments of all vibrational modes were performed by potential energy distributions using VEDA 4 program. The geometrical parameters of the optimized structure are in good agreement with the X-ray crystallographic data, and the theoretical vibrational frequencies and GIAO (1)H and (13)C NMR chemical shifts show good agreement with experimental values. Besides, molecular electrostatic potential (MEP) distribution, frontier molecular orbitals (FMO) and non-linear optical properties of the title compound were investigated by theoretical calculations at the B3LYP/6-311G(d,p) level. The linear polarizabilities and first hyper polarizabilities of the molecule indicate that the compound is a good candidate of nonlinear optical materials. The thermodynamic properties of the compound at different temperatures were calculated, revealing the correlations between standard heat capacity, standard entropy, standard enthalpy changes and temperatures. Copyright © 2012 Elsevier B.V. All rights reserved.

Synthesis, crystal structure, Hirshfeld surfaces analysis and anti-ischemic activity of cinnamide derivatives

NASA Astrophysics Data System (ADS)

Zhong, Jian-gang; Han, Jia-pei; Li, Xiao-feng; Xu, Yi; Zhong, Yan; Wu, Bin

2018-02-01

Two cinnamide derivatives, namely, (E)-1-(4-(bis(4-methylphenyl)- methyl)piperazin-1-yl)-3-(3,4-diethoxyphenyl)prop-2-en-1-one (5) and (E)-1-(4-(bis- (4-fluorophenyl)methyl)piperazin-1-yl)-3-(4-methoxyphenyl)prop-2-en-1-one (6), have been synthesized and characterized by IR spectra, High resolution mass spectra, 1H NMR spectra, 13C NMR spectra. The compound 5 is a novel compound and has never been reported in the literature. Their crystal structures were studied by single-crystal X-ray diffraction. They all crystallize in the monoclinic system. The single-crystal X-ray revealed that compound 5 has infinite X-shaped 1-D polymeric chains structure and compound 6 has a layered 3-D structure by intermolecular interactions. Hirshfeld surface analysis demonstrated the presence of H⋯H, O⋯H, C⋯H, F⋯H, Csbnd H⋯π and π⋯π intermolecular interactions. In addition, the MTT assay results indicated that the compounds 5 and 6 display effective activities against neurotoxicity which is induced by glutamine in PC12 cells. The in vivo experiment indicated that the compound 6 has a good protective effect on cerebral infarction.

N-(4-Nitrobenzoyl)-N'-(1,5-dimethyl-3-oxo-2-phenyl-1H-3(2H)-pyrazolyl)-thiourea hydrate: Synthesis, spectroscopic characterization, X-ray structure and DFT studies

NASA Astrophysics Data System (ADS)

Arslan, N. Burcu; Kazak, Canan; Aydın, Fatma

2012-04-01

The title molecule (C19H17N5O4S·H2O) was synthesized and characterized by IR-NMR spectroscopy, MS and single-crystal X-ray diffraction. The molecular geometry, vibrational frequencies and gauge-independent atomic orbital (GIAO) 1H and 13C NMR chemical shift values of the compound in the ground state have been calculated by using the density functional theory (DFT) method with 6-31G(d) basis set, and compared with the experimental data. All the assignments of the theoretical frequencies were performed by potential energy distributions using VEDA 4 program. The calculated results show that the optimized geometries can well reproduce the crystal structural parameters, and the theoretical vibrational frequencies and 1H and 13C NMR chemical shift values show good agreement with experimental data. To determine conformational flexibility, the molecular energy profile of the title compound was obtained with respect to the selected torsion angle, which was varied from -180° to +180° in steps of 10°. Besides, molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis and thermodynamic properties of the compound were investigated by theoretical calculations.

Four new polymorphic forms of suplatast tosilate.

PubMed

Nagai, Keiko; Ushio, Takanori; Miura, Hidenori; Nakamura, Takashi; Moribe, Kunikazu; Yamamoto, Keiji

2014-01-02

We found four new polymorphic forms (γ-, ε-, ζ-, and η-forms) of suplatast tosilate (ST) by recrystallization and seeding with ST-analogous compounds; three polymorphic forms (α-, β-, and δ-forms) of ST have been previously reported. The physicochemical properties of these new forms were investigated using infrared (IR) spectroscopy, solid-state nuclear magnetic resonance (NMR) spectroscopy, differential scanning calorimetry, and powder X-ray diffractometry. The presence of hydrogen bonds in the new forms was assessed from the IR and solid-state NMR spectra. The crystal structures of the ε- and η-forms were determined from their powder X-ray diffraction data using the direct space approach and the Monte Carlo method, followed by Rietveld refinement. The structures determined for the ε- and η-forms supported the presence of hydrogen bonds between the ST molecules, as the IR and solid-state NMR spectra indicated. The thermodynamic characteristics of the seven polymorphic forms were evaluated by determining the solubility of each form. The α-form was the most insoluble in 2-propanol at 35°C, and was thus concluded to be the most stable form. The ε-form was the most soluble, and a polymorphic transition from the ε- to the α-form was observed during solubility testing. Copyright © 2013 Elsevier B.V. All rights reserved.

Chemical and structural analysis of gallstones from the Indian subcontinent.

PubMed

Ramana Ramya, J; Thanigai Arul, K; Epple, M; Giebel, U; Guendel-Graber, J; Jayanthi, V; Sharma, M; Rela, M; Narayana Kalkura, S

2017-09-01

Representative gallstones from north and southern parts of India were analyzed by a combination of physicochemical methods: X-ray diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), CHNS analysis, thermal analysis and Nuclear Magnetic Resonance (NMR) spectroscopy ( 1 H and 13 C). The stones from north Indian were predominantly consisting of cholesterol monohydrate and anhydrous cholesterol which was confirmed by XRD analysis. FTIR spectroscopy confirmed the presence of cholesterol and calcium bilirubinate in the south Indian gallstones. EDX spectroscopy revealed the presence of carbon, nitrogen, oxygen, calcium, sulfur, sodium and magnesium and chloride in both south Indian and north Indian gallstones. FTIR and NMR spectroscopy confirmed the occurrence of cholesterol in north Indian gallstones. The respective colour of the north Indian and south Indian gallstones was yellowish and black. The morphology of the constituent crystals of the north Indian and south Indian gallstones were platy and globular respectively. The appreciable variation in colour, morphology and composition of south and north Indian gallstones may be due to different food habit and habitat. Copyright © 2017 Elsevier B.V. All rights reserved.

Modeling the intermolecular interactions: molecular structure of N-3-hydroxyphenyl-4-methoxybenzamide.

PubMed

Karabulut, Sedat; Namli, Hilmi; Kurtaran, Raif; Yildirim, Leyla Tatar; Leszczynski, Jerzy

2014-03-01

The title compound, N-3-hydroxyphenyl-4-methoxybenzamide (3) was prepared by the acylation reaction of 3-aminophenol (1) and 4-metoxybenzoylchloride (2) in THF and characterized by ¹H NMR, ¹³C NMR and elemental analysis. Molecular structure of the crystal was determined by single crystal X-ray diffraction and DFT calculations. 3 crystallizes in monoclinic P2₁/c space group. The influence of intermolecular interactions (dimerization and crystal packing) on molecular geometry has been evaluated by calculations performed for three different models; monomer (3), dimer (4) and dimer with added unit cell contacts (5). Molecular structure of 3, 4 and 5 was optimized by applying B3LYP method with 6-31G+(d,p) basis set in gas phase and compared with X-ray crystallographic data including bond lengths, bond angles and selected dihedral angles. It has been concluded that although the crystal packing and dimerization have a minor effect on bond lengths and angles, however, these interactions are important for the dihedral angles and the rotational conformation of aromatic rings. Copyright © 2013 Elsevier Inc. All rights reserved.

Synthesis and structural and conformational study of some esters derived from 8-β-hydroxy-3-phenethyl-3- azabicyclico [3.2.11] octan-8-α-carboxylic acid

NASA Astrophysics Data System (ADS)

Diez, M.; Izquierdo, M. L.; Arias, M. S.; Galvez, E.; Matesanz, E.; Martinez-Ripoll, M.

1991-09-01

A series of 8-β-hydroxy-8-α-alkoxycarbonyl- N-phenethyl-3-azabicyclo [3.2.1.]octane derivatives have been synthesized and studied by IR, 1H and 13C NMR spectroscopy, and the crystal structure of ethyl-8-β-hydroxy-3-phenethyl-3-azabicyclo [3.2.1] octan-8-α-carboxylate ( Va) has been determined by X-ray diffraction. In deuterochloroform and deuterobenzene the cyclopentane and piperidine rings of the title compounds show an envelope conformation flattened at C8 and a distorted chair conformation puckered at C8 and flattened at N3, respectively, with the N-substituent in an equatorial position. These results are in close agreement with that found for compound Va in the crystalline state. By comparing the NMR and X-ray parameters of the title compounds with those of the corresponding 8-α-hydroxy-8β-alkoxycarbonyl- N-phenethyl-3- azabicyclo [3.2.1] octane epimers and 3-phenethyl-3-azabicyclo [3.2.1] octan-8-α-(andβ)ol, several stereoelectronic effects have been deduced.

X-ray diffraction from shock-loaded polycrystals.

PubMed

Swift, Damian C

2008-01-01

X-ray diffraction was demonstrated from shock-compressed polycrystalline metals on nanosecond time scales. Laser ablation was used to induce shock waves in polycrystalline foils of Be, 25-125 microm thick. A second laser pulse was used to generate a plasma x-ray source by irradiation of a Ti foil. The x-ray source was collimated to produce a beam of controllable diameter, which was directed at the Be sample. X-rays were diffracted from the sample, and detected using films and x-ray streak cameras. The diffraction angle was observed to change with shock pressure. The diffraction angles were consistent with the uniaxial (elastic) and isotropic (plastic) compressions expected for the loading conditions used. Polycrystalline diffraction will be used to measure the response of the crystal lattice to high shock pressures and through phase changes.

Revisiting Cu 63 NMR evidence for charge order in superconducting La 1.885 Sr 0.115 CuO 4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Imai, T.; Takahashi, S. K.; Arsenault, A.

Here, the presence of charge and spin stripe order in the La 2CuO 4-based family of superconductors continues to lead to new insight on the unusual ground-state properties of high- T c cuprates. Soon after the discovery of charge stripe order at T charge≃65 K in Nd 3+ co-doped La 1.48Nd 0.4Sr 0.12CuO 4( Tc≃6 K), Hunt et al. demonstrated that La 1.48Nd 0.4Sr 0.12CuO 4 and superconducting La 2–xSr xCuO 4 with x~1/8( Tc≃30 K) share nearly identical NMR anomalies near Tcharge of the former. Their inevitable conclusion that La 1.885Sr 0.115CuO 4 also undergoes charge order at amore » comparable temperature became controversial, because diffraction measurements at the time were unable to detect Bragg peaks associated with charge order. Recent advances in x-ray diffraction techniques finally led to definitive confirmations of the charge order Bragg peaks in La 1.885Sr 0.115CuO 4 with an onset at as high as Tcharge≃80 K. Meanwhile, improved instrumental technology has enabled routine NMR measurements that were not feasible two decades ago. Motivated by these new developments, we revisit the charge order transition of a La 1.885Sr 0.115CuO 4 single crystal based on 63Cu NMR techniques. We demonstrate that 63Cu NMR properties of the nuclear spin I z=–1/2 to +1/2 central transition below Tcharge exhibit unprecedentedly strong dependence on the measurement time scale set by the separation time τ between the 90° and 180° radio-frequency pulses; a new kind of anomalous, very broad winglike 63Cu NMR signals gradually emerge below Tcharge only for extremely short τ≲4μs, while the spectral weight I Normal of the normal NMR signals is progressively wiped out. The NMR linewidth and relaxation rates depend strongly on τ below Tcharge, and their enhancement in the charge ordered state indicates that charge order turns on strong but inhomogeneous growth of Cu spin-spin correlations.« less

Revisiting Cu 63 NMR evidence for charge order in superconducting La 1.885 Sr 0.115 CuO 4

DOE PAGES

Imai, T.; Takahashi, S. K.; Arsenault, A.; ...

2017-12-26

Here, the presence of charge and spin stripe order in the La 2CuO 4-based family of superconductors continues to lead to new insight on the unusual ground-state properties of high- T c cuprates. Soon after the discovery of charge stripe order at T charge≃65 K in Nd 3+ co-doped La 1.48Nd 0.4Sr 0.12CuO 4( Tc≃6 K), Hunt et al. demonstrated that La 1.48Nd 0.4Sr 0.12CuO 4 and superconducting La 2–xSr xCuO 4 with x~1/8( Tc≃30 K) share nearly identical NMR anomalies near Tcharge of the former. Their inevitable conclusion that La 1.885Sr 0.115CuO 4 also undergoes charge order at amore » comparable temperature became controversial, because diffraction measurements at the time were unable to detect Bragg peaks associated with charge order. Recent advances in x-ray diffraction techniques finally led to definitive confirmations of the charge order Bragg peaks in La 1.885Sr 0.115CuO 4 with an onset at as high as Tcharge≃80 K. Meanwhile, improved instrumental technology has enabled routine NMR measurements that were not feasible two decades ago. Motivated by these new developments, we revisit the charge order transition of a La 1.885Sr 0.115CuO 4 single crystal based on 63Cu NMR techniques. We demonstrate that 63Cu NMR properties of the nuclear spin I z=–1/2 to +1/2 central transition below Tcharge exhibit unprecedentedly strong dependence on the measurement time scale set by the separation time τ between the 90° and 180° radio-frequency pulses; a new kind of anomalous, very broad winglike 63Cu NMR signals gradually emerge below Tcharge only for extremely short τ≲4μs, while the spectral weight I Normal of the normal NMR signals is progressively wiped out. The NMR linewidth and relaxation rates depend strongly on τ below Tcharge, and their enhancement in the charge ordered state indicates that charge order turns on strong but inhomogeneous growth of Cu spin-spin correlations.« less

Single-pulse x-ray diffraction using polycapillary optics for in situ dynamic diffraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maddox, B. R., E-mail: maddox3@llnl.gov; Akin, M. C., E-mail: akin1@llnl.gov; Teruya, A.

2016-08-15

Diagnostic use of single-pulse x-ray diffraction (XRD) at pulsed power facilities can be challenging due to factors such as the high flux and brightness requirements for diffraction and the geometric constraints of experimental platforms. By necessity, the x-ray source is usually positioned very close, within a few inches of the sample. On dynamic compression platforms, this puts the x-ray source in the debris field. We coupled x-ray polycapillary optics to a single-shot needle-and-washer x-ray diode source using a laser-based alignment scheme to obtain high-quality x-ray diffraction using a single 16 ns x-ray pulse with the source >1 m from themore » sample. The system was tested on a Mo sample in reflection geometry using 17 keV x-rays from a Mo anode. We also identified an anode conditioning effect that increased the x-ray intensity by 180%. Quantitative measurements of the x-ray focal spot produced by the polycapillary yielded a total x-ray flux on the sample of 3.3 ± 0.5 × 10{sup 7} molybdenum Kα photons.« less

Characterizing the Secondary Protein Structure of Black Widow Dragline Silk Using Solid-State NMR & X-ray Diffraction

PubMed Central

Jenkins, Janelle E.; Sampath, Sujatha; Butler, Emily; Kim, Jihyun; Henning, Robert W.; Holland, Gregory P.; Yarger, Jeffery L.

2013-01-01

This study provides a detailed secondary structural characterization of major ampullate dragline silk from Latrodectus hesperus (black widow) spiders. X-ray diffraction results show that the structure of black widow major ampullate silk fibers is comprised of stacked β-sheet nanocrystallites oriented parallel to the fiber axis and an amorphous region with oriented (anisotropic) and isotropic components. The combination of two-dimensional (2D) 13C-13C through-space and through-bond solid-state NMR experiments provide chemical shifts that are used to determine detailed information about amino acid motif secondary structure in black widow spider dragline silk. Individual amino acids are incorporated into different repetitive motifs that make up the majority of this protein-based biopolymer. From the solid-state NMR measurements, we assign distinct secondary conformations to each repetitive amino acid motif and hence to the amino acids that make up the motifs. Specifically, alanine is incorporated in β-sheet (poly(Alan) and poly(Gly-Ala)), 31-helix (poly(Gly-Gly-Xaa), and α-helix (poly(Gln-Gln-Ala-Tyr)) components. Glycine is determined to be in β-sheet (poly(Gly-Ala)) and 31-helical (poly(Gly-Gly-Xaa)) regions, while serine is present in β-sheet (poly(Gly-Ala-Ser)), 31-helix (poly(Gly-Gly-Ser)), and β-turn (poly(Gly-Pro-Ser)) structures. These various motif-specific secondary structural elements are quantitatively correlated to the primary amino acid sequence of major ampullate spidroin 1 and 2 (MaSp1 and MaSp2) and are shown to form a self-consistent model for black widow dragline silk. PMID:24024617

MAS-NMR studies of lithium aluminum silicate (LAS) glasses and glass-ceramics having different Li 2O/Al 2O 3 ratio

NASA Astrophysics Data System (ADS)

Ananthanarayanan, A.; Kothiyal, G. P.; Montagne, L.; Revel, B.

2010-01-01

Emergence of phases in lithium aluminum silicate (LAS) glasses of composition (wt%) xLi 2O-71.7SiO 2-(17.7- x)Al 2O 3-4.9K 2O-3.2B 2O 3-2.5P 2O 5 (5.1≤ x≤12.6) upon heat treatment were studied. 29Si, 27Al, 31P and 11B MAS-NMR were employed for structural characterization of both LAS glasses and glass-ceramics. In glass samples, Al is found in tetrahedral coordination, while P exists mainly in the form of orthophosphate units. B exists as BO 3 and BO 4 units. 27Al NMR spectra show no change with crystallization, ruling out the presence of any Al containing phase. Contrary to X-ray diffraction studies carried out, 11B (high field 18.8 T) and 29Si NMR spectra clearly indicate the unexpected crystallization of a borosilicate phase (Li,K)BSi 2O 6, whose structure is similar to the aluminosilicate virgilite. Also, lithium disilicate (Li 2Si 2O 5), lithium metasilicate (Li 2SiO 3) and quartz (SiO 2) were identified in the 29Si NMR spectra of the glass-ceramics. 31P NMR spectra of the glass-ceramics revealed the presence of Li 3PO 4 and a mixed phase (Li,K) 3PO 4 at low alkali concentrations.

Probing the role of ceramide hydroxylation in skin barrier lipid models by 2H solid-state NMR spectroscopy and X-ray powder diffraction.

PubMed

Kováčik, Andrej; Vogel, Alexander; Adler, Juliane; Pullmannová, Petra; Vávrová, Kateřina; Huster, Daniel

2018-05-01

In this work, we studied model stratum corneum lipid mixtures composed of the hydroxylated skin ceramides N-lignoceroyl 6-hydroxysphingosine (Cer[NH]) and α-hydroxylignoceroyl phytosphingosine (Cer[AP]). Two model skin lipid mixtures of the composition Cer[NH] or Cer[AP], N-lignoceroyl sphingosine (Cer[NS]), lignoceric acid (C24:0) and cholesterol in a 0.5:0.5:1:1 molar ratio were compared. Model membranes were investigated by differential scanning calorimetry and 2 H solid-state NMR spectroscopy at temperatures from 25 °C to 80 °C. Each component of the model mixture was specifically deuterated for selective detection by 2 H NMR. Thus, the exact phase composition of the mixture at varying temperatures could be quantified. Moreover, using X-ray powder diffraction we investigated the lamellar phase formation. From the solid-state NMR and DSC studies, we found that both hydroxylated Cer[NH] and Cer[AP] exhibit a similar phase behavior. At physiological skin temperature of 32 °C, the lipids form a crystalline (orthorhombic) phase. With increasing temperature, most of the lipids become fluid and form a liquid-crystalline phase, which converts to the isotropic phase at higher temperatures (65-80 °C). Interestingly, lignoceric acid in the Cer[NH]-containing mixture has a tendency to form two types of fluid phases at 65 °C. This tendency was also observed in Cer[AP]-containing membranes at 80 °C. While Cer[AP]-containing lipid models formed a short periodicity phase featuring a repeat spacing of d = 5.4 nm, in the Cer[NH]-based model skin lipid membranes, the formation of unusual long periodicity phase with a repeat spacing of d = 10.7 nm was observed. Copyright © 2018 Elsevier B.V. All rights reserved.

Tetraalkylammonium Salts as Hydrogen-Bonding Catalysts.

PubMed

Shirakawa, Seiji; Liu, Shiyao; Kaneko, Shiho; Kumatabara, Yusuke; Fukuda, Airi; Omagari, Yumi; Maruoka, Keiji

2015-12-21

Although the hydrogen-bonding ability of the α hydrogen atoms on tetraalkylammonium salts is often discussed with respect to phase-transfer catalysts, catalysis that utilizes the hydrogen-bond-donor properties of tetraalkylammonium salts remains unknown. Herein, we demonstrate hydrogen-bonding catalysis with newly designed tetraalkylammonium salt catalysts in Mannich-type reactions. The structure and the hydrogen-bonding ability of the new ammonium salts were investigated by X-ray diffraction analysis and NMR titration studies. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bisindole alkaloids from Tabernaemontana corymbosa.

PubMed

Zhang, Bing-Jie; Lu, Jing-Song; Bao, Mei-Fen; Zhong, Xiu-Hong; Ni, Ling; Wu, Jing; Cai, Xiang-Hai

2018-05-11

Continued study in bioactive monoterpenoid alkaloids led to the isolation of nine undescribed alkaloids, taberyunines A-I, together with 32 known ones from the aerial parts of Tabernaemontana corymbosa Roxb. ex Wall (Apocynaceae). Among the undescribed alkaloids, taberyunines A-G and H-I were assigned to Aspidosperma-Aspidosperma and Vobasinyl-Ibogan type bisindoles, respectively. Their structures were determined by NMR spectra, MS data and X-ray diffraction. Taberyunine B showed significant cytotoxicity against three cancer cell lines. Copyright © 2018 Elsevier Ltd. All rights reserved.

Growth and characterization of metal halide perovskite crystals: Benzyltributyl ammonium tetrachloro manganate(II) monohydrate

NASA Astrophysics Data System (ADS)

Dhandapani, M.; Sugandhi, K.; Nithya, S.; Muthuraja, P.; Balachandar, S.; Aranganayagam, K. R.

2018-05-01

The perovskite type organic-inorganic hybrid benzyltributyl ammoniumtetrachloro manganate (II) monohydrates (BTBA-Mn) are synthesized and the single crystals are grown by slow evaporation solution growth technique. The structure of the grown crystals are confirmed by using X-ray diffraction (XRD), unit cell parameter analysis, Fourier transform Infrared (FTIR), elemental analysis and 13C-NMR spectral studies. Thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning colorimetric (DSC) analysis were carried out to understand thermal stability and occurrence of phase transition.

Regioselective hypervalent iodine-induced Favorskii rearrangement of 3-oxo-5β-steroids.

PubMed

Viviano-Posadas, Alejandro O; Flores-Álamo, Marcos; Iglesias-Arteaga, Martín A

2016-09-01

Treatment of 3-oxo-5β-steroids with diacetoxyiodobenzene/KOH triggered a fast and regioselective Favorskii rearrangement that exclusively led to 3β-methoxycarbonyl-5β-4-norsteroids in good yields. The outcome of the reaction indicates that although both Cyclopropanone and Semi-benzylic pathways are possible, in the case of 3-oxo-5β-steroids, only the last participates. Unambiguous characterization of the products was achieved by NMR and X-ray Diffraction studies. Copyright © 2016 Elsevier Inc. All rights reserved.

Isopalhinine A, a unique pentacyclic Lycopodium alkaloid from Palhinhaea cernua.

PubMed

Dong, Liao-Bin; Gao, Xiu; Liu, Fei; He, Juan; Wu, Xing-De; Li, Yan; Zhao, Qin-Shi

2013-07-19

A new pentacyclic (5/6/6/6/7) Lycopodium alkaloid named isopalhinine A (1), which possesses a sterically congested architecture built with a tricyclo[4.3.1.0(3,7)]decane (isotwistane) moiety and a 1-azabicyclo[4.3.1]decane moiety, and palhinines B (2) and C (3) were isolated from Palhinhaea cernua. The structure and absolute configuration of 1 were elucidated by a combination of NMR spectra, optical rotation calculation, and X-ray diffraction experiment. A possible biogenetic pathway was also proposed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luong Thi, T. T., E-mail: thuyltt@hnue.edu.vn; Nguyen Bich, N.; Nguyen, H.

Two 4-substituted 2,2'-bipyridines, namely 4-(ferrocenylethynyl)-2,2'-bipyridine (I) and 4-ferrocenyl-2,2'-bipyridine (II) have been synthesized and fully characterized via single-crystal X-ray diffraction and {sup 1}H and {sup 13}C NMR analyses. The π-conjugated system designed from 2,2'-bipyridine modified with the ferrocenylethynyl and ferrocenyl groups shows the desired planarity. In the crystal packing of I and II, the molecules arrange themselves in head-to-tail and head-to-head motifs, respectively, resulting in consecutive layers of ferrocene and pyridine moieties.

Structural changes of starch during baking and staling of rye bread.

PubMed

Mihhalevski, Anna; Heinmaa, Ivo; Traksmaa, Rainer; Pehk, Tõnis; Mere, Arvo; Paalme, Toomas

2012-08-29

Rye sourdough breads go stale more slowly than wheat breads. To understand the peculiarities of bread staling, rye sourdough bread, wheat bread, and a number of starches were studied using wide-angle X-ray diffraction, nuclear magnetic resonance ((13)C CP MAS NMR, (1)H NMR, (31)P NMR), polarized light microscopy, rheological methods, microcalorimetry, and measurement of water activity. The degree of crystallinity of starch in breads decreased with hydration and baking to 3% and increased during 11 days of storage to 21% in rye sourdough bread and to 26% in wheat bread. (13)C NMR spectra show that the chemical structures of rye and wheat amylopectin and amylose contents are very similar; differences were found in the starch phospholipid fraction characterized by (31)P NMR. The (13)C CP MAS NMR spectra demonstrate that starch in rye sourdough breads crystallize in different forms than in wheat bread. It is proposed that different proportions of water incorporation into the crystalline structure of starch during staling and changes in starch fine structure cause the different rates of staling of rye and wheat bread.

Dynamics and interactions of ibuprofen in cyclodextrin nanosponges by solid-state NMR spectroscopy

PubMed Central

Ferro, Monica; Pastori, Nadia; Punta, Carlo; Melone, Lucio; Panzeri, Walter; Rossi, Barbara; Trotta, Francesco

2017-01-01

Two different formulations of cyclodextrin nanosponges (CDNS), obtained by polycondensation of β-cyclodextrin with ethylenediaminetetraacetic acid dianhydride (EDTAn), were treated with aqueous solutions of ibuprofen sodium salt (IbuNa) affording hydrogels that, after lyophilisation, gave two solid CDNS-drug formulations. 1H fast MAS NMR and 13C CP-MAS NMR spectra showed that IbuNa was converted in situ into its acidic and dimeric form (IbuH) after freeze-drying. 13C CP-MAS NMR spectra also indicated that the structure of the nanosponge did not undergo changes upon drug loading compared to the unloaded system. However, the 13C NMR spectra collected under variable contact time cross-polarization (VCT-CP) conditions showed that the polymeric scaffold CDNS changed significantly its dynamic regime on passing from the empty CDNS to the drug-loaded CDNS, thus showing that the drug encapsulation can be seen as the formation of a real supramolecular aggregate rather than a conglomerate of two solid components. Finally, the structural features obtained from the different solid-state NMR approaches reported matched the information from powder X-ray diffraction profiles. PMID:28228859

Dynamics and interactions of ibuprofen in cyclodextrin nanosponges by solid-state NMR spectroscopy.

PubMed

Ferro, Monica; Castiglione, Franca; Pastori, Nadia; Punta, Carlo; Melone, Lucio; Panzeri, Walter; Rossi, Barbara; Trotta, Francesco; Mele, Andrea

2017-01-01

Two different formulations of cyclodextrin nanosponges (CDNS), obtained by polycondensation of β-cyclodextrin with ethylenediaminetetraacetic acid dianhydride (EDTAn), were treated with aqueous solutions of ibuprofen sodium salt (IbuNa) affording hydrogels that, after lyophilisation, gave two solid CDNS-drug formulations. 1 H fast MAS NMR and 13 C CP-MAS NMR spectra showed that IbuNa was converted in situ into its acidic and dimeric form (IbuH) after freeze-drying. 13 C CP-MAS NMR spectra also indicated that the structure of the nanosponge did not undergo changes upon drug loading compared to the unloaded system. However, the 13 C NMR spectra collected under variable contact time cross-polarization (VCT-CP) conditions showed that the polymeric scaffold CDNS changed significantly its dynamic regime on passing from the empty CDNS to the drug-loaded CDNS, thus showing that the drug encapsulation can be seen as the formation of a real supramolecular aggregate rather than a conglomerate of two solid components. Finally, the structural features obtained from the different solid-state NMR approaches reported matched the information from powder X-ray diffraction profiles.

Evidence for novel beta-sheet structures in Iowa mutant beta-amyloid fibrils.

PubMed

Tycko, Robert; Sciarretta, Kimberly L; Orgel, Joseph P R O; Meredith, Stephen C

2009-07-07

Asp23-to-Asn mutation within the coding sequence of beta-amyloid, called the Iowa mutation, is associated with early onset, familial Alzheimer's disease and cerebral amyloid angiopathy, in which patients develop neuritic plaques and massive vascular deposition predominantly of the mutant peptide. We examined the mutant peptide, D23N-Abeta40, by electron microscopy, X-ray diffraction, and solid-state NMR spectroscopy. D23N-Abeta40 forms fibrils considerably faster than the wild-type peptide (k = 3.77 x 10(-3) min(-1) and 1.07 x 10(-4) min(-1) for D23N-Abeta40 and the wild-type peptide WT-Abeta40, respectively) and without a lag phase. Electron microscopy shows that D23N-Abeta40 forms fibrils with multiple morphologies. X-ray fiber diffraction shows a cross-beta pattern, with a sharp reflection at 4.7 A and a broad reflection at 9.4 A, which is notably smaller than the value for WT-Abeta40 fibrils (10.4 A). Solid-state NMR measurements indicate molecular level polymorphism of the fibrils, with only a minority of D23N-Abeta40 fibrils containing the in-register, parallel beta-sheet structure commonly found in WT-Abeta40 fibrils and most other amyloid fibrils. Antiparallel beta-sheet structures in the majority of fibrils are indicated by measurements of intermolecular distances through (13)C-(13)C and (15)N-(13)C dipole-dipole couplings. An intriguing possibility exists that there is a relationship between the aberrant structure of D23N-Abeta40 fibrils and the unusual vasculotropic clinical picture in these patients.

Synthesis and characterization of silver nanoparticles from (bis)alkylamine silver carboxylate precursors

NASA Astrophysics Data System (ADS)

Uznanski, Pawel; Zakrzewska, Joanna; Favier, Frederic; Kazmierski, Slawomir; Bryszewska, Ewa

2017-03-01

A comparative study of amine and silver carboxylate adducts [R1COOAg-2(R2NH2)] (R1 = 1, 7, 11; R2 = 8, 12) as a key intermediate in NPs synthesis is carried out via differential scanning calorimetry, solid-state FT-infrared spectroscopy, 13C CP MAS NMR, powder X-ray diffraction and X-ray photoelectron spectroscopy, and various solution NMR spectroscopies (1H and 13C NMR, pulsed field gradient spin-echo NMR, and ROESY). It is proposed that carboxyl moieties in the presence of amine ligands are bound to silver ions via chelating bidentate type of coordination as opposed to bridging bidentate coordination of pure silver carboxylates resulting from the formation of dimeric units. All complexes are packed as lamellar bilayer structures. Silver carboxylate/amine complexes show one first-order melting transition. The evidence presented in this study shows that phase behavior of monovalent metal carboxylates are controlled, mainly, by head group bonding. In solution, insoluble silver salt is stabilized by amine molecules which exist in dynamic equilibrium. Using (bis)amine-silver carboxylate complex as precursor, silver nanoparticles were fabricated. During high-temperature thermolysis, the (bis)amine-carboxylate adduct decomposes to produce silver nanoparticles of small size. NPs are stabilized by strongly interacting carboxylate and trace amounts of amine derived from the silver precursor interacting with carboxylic acid. A corresponding aliphatic amide obtained from silver precursor at high-temperature reaction conditions is not taking part in the stabilization. Combining NMR techniques with FTIR, it was possible to follow an original stabilization mechanism.

X-Ray Diffraction Apparatus

NASA Technical Reports Server (NTRS)

Blake, David F. (Inventor); Bryson, Charles (Inventor); Freund, Friedmann (Inventor)

1996-01-01

An x-ray diffraction apparatus for use in analyzing the x-ray diffraction pattern of a sample is introduced. The apparatus includes a beam source for generating a collimated x-ray beam having one or more discrete x-ray energies, a holder for holding the sample to be analyzed in the path of the beam, and a charge-coupled device having an array of pixels for detecting, in one or more selected photon energy ranges, x-ray diffraction photons produced by irradiating such a sample with said beam. The CCD is coupled to an output unit which receives input information relating to the energies of photons striking each pixel in the CCD, and constructs the diffraction pattern of photons within a selected energy range striking the CCD.

Synthesis, spectral, thermal, X-ray single crystal of new RuCl₂(dppb)diamine complexes and their application in hydrogenation of Cinnamic aldehyde.

PubMed

Warad, Ismail; Al-Hussain, Hanan; Al-Far, Rawhi; Mahfouz, Refaat; Hammouti, Belkheir; Hadda, Taibi Ben

2012-09-01

The preparation of new three trans-[RuCl(2)(dppb)(N-N)] with mixed diamine (N-N) and 1,4-bis-(diphenylphosphino)butane (dppb) ligands, starting from RuCl(2)(PPh(3))(3) as precursor is presented. The complexes are characterized on the basis of elemental analysis, IR, (1)H, (13)C and (31)P{(1)H}NMR, FAB-MS, TG/DTA and single crystal X-ray diffraction studies. Complex (2L(1)) crystallizes in the monoclinic unit cells with the space group P2(1). The catalysts are evaluated for their Cinnamic aldehyde hydrogenation. The catalysts show excellent activity and selectivity for the unsaturated carbonyl compound under mild conditions. Copyright © 2012 Elsevier B.V. All rights reserved.

NMR Knight shifts and the electronic properties of Rb{sub 8}Na{sub 16}Si{sub 136} clathrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Latturner, Susan; Iversen, Bo B.; Sepa, Jelena

2001-03-15

A silicon framework clathrate type-II compound was synthesized with rubidium and sodium atoms in cages. A single crystal of this material was characterized by both conventional and synchrotron x-ray diffraction; the structure belongs to the cubic space group Fd-3m, with a cell edge of 14.738(1) Aa. The alkali metals are ordered in the structure, with the small cages containing sodium, and the large cages containing rubidium. Variable temperature magic-angle-spinning NMR of all three nuclei show large Knight shifts with a strong temperature dependence, unlike conventional metals. The low conductivity (200 S/cm) and high paramagnetic susceptibility (5x10{sup -6}emu/g) indicate that asmore » the temperature is lowered, the electrons become more localized on the alkali atoms, resulting in properties consistent with a correlated narrow band metal system.« less

Real-time X-ray Diffraction: Applications to Materials Characterization

NASA Technical Reports Server (NTRS)

Rosemeier, R. G.

1984-01-01

With the high speed growth of materials it becomes necessary to develop measuring systems which also have the capabilities of characterizing these materials at high speeds. One of the conventional techniques of characterizing materials was X-ray diffraction. Film, which is the oldest method of recording the X-ray diffraction phenomenon, is not quite adequate in most circumstances to record fast changing events. Even though conventional proportional counters and scintillation counters can provide the speed necessary to record these changing events, they lack the ability to provide image information which may be important in some types of experiment or production arrangements. A selected number of novel applications of using X-ray diffraction to characterize materials in real-time are discussed. Also, device characteristics of some X-ray intensifiers useful in instantaneous X-ray diffraction applications briefly presented. Real-time X-ray diffraction experiments with the incorporation of image X-ray intensification add a new dimension in the characterization of materials. The uses of real-time image intensification in laboratory and production arrangements are quite unlimited and their application depends more upon the ingenuity of the scientist or engineer.

Operando NMR and XRD study of chemically synthesized LiCx oxidation in a dry room environment

DOE PAGES

Sacci, Robert L.; Gill, Lance W.; Hagaman, Edward W.; ...

2015-04-07

We test the stability of pre-lithiated graphite anodes for Li-ion batteries in a dry room battery processing room. The reaction between LiCx and laboratory air was followed using operando NMR and x-ray diffraction as these methods are sensitive to change in Li stoichiometry in graphite. There is minimal reactivity between LiC 6 and N 2, CO 2 or O 2; however, LiC 6 reacts with moisture to form lithium (hydr)oxide. The reaction rate follows zero-order kinetics with respects to intercalated lithium suggesting that lithium transport through the graphite is fast. The reaction mechanism occurs by sequential formation of higher stagesmore » LiC 12, then LiC 18, and then LiC 24 as the hydrolysis proceeds to the formation of Li xOH y and graphite end products. Slowing down the formation rate of the Li xOH y passivation layer stabilizes of the higher stages.« less

Surface modification of calcium fluoro and hydroxyapatite by 1-octylphosphonic dichloride

NASA Astrophysics Data System (ADS)

Aissa, Abdallah; Agougui, Hassen; Debbabi, Mongi

2011-08-01

The reactivity of the surface of calcium hydroxyapatite (CaHAp) and fluorapatite (CaFAp) was tested and compared by grafting the 1-octylphosphonic dichloride (C 8H 17OPCl 2) using a molar ratio x = 2 or 4, x = n(organic)/ n(apatite). Successful synthesis was confirmed by different characterisation techniques such as X-ray powder diffraction patterns, IR spectroscopy, MAS-NMR ( 1H and 31P) and chemical analysis. The difference between their specific surface area (SSA: 57.46 for HAp and 12.09 m 2/g for FAp), the percentage of carbon measured after treatment with (C 8H 17OPCl 2) and the intensities of IR bands attributed to the grafted moiety suggests that the surface of hydroxyapatite is more reactive than that of fluorapatite. The 31P CP-MAS-NMR spectra of treated fluorapatite show a significant change in isotropic signal due to the protonation and deprotonation of superficial phosphate group. This can be explained by the difference in the nature of inorganic material.

Radiation damage free ghost diffraction with atomic resolution

DOE PAGES

Li, Zheng; Medvedev, Nikita; Chapman, Henry N.; ...

2017-12-21

The x-ray free electron lasers can enable diffractive structural determination of protein nanocrystals and single molecules that are too small and radiation-sensitive for conventional x-ray diffraction. However the electronic form factor may be modified during the ultrashort x-ray pulse due to photoionization and electron cascade caused by the intense x-ray pulse. For general x-ray imaging techniques, the minimization of the effects of radiation damage is of major concern to ensure reliable reconstruction of molecular structure. Here in this paper, we show that radiation damage free diffraction can be achieved with atomic spatial resolution by using x-ray parametric down-conversion and ghostmore » diffraction with entangled photons of x-ray and optical frequencies. We show that the formation of the diffraction patterns satisfies a condition analogous to the Bragg equation, with a resolution that can be as fine as the crystal lattice length scale of several Ångstrom. Since the samples are illuminated by low energy optical photons, they can be free of radiation damage.« less

Radiation damage free ghost diffraction with atomic resolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Zheng; Medvedev, Nikita; Chapman, Henry N.

The x-ray free electron lasers can enable diffractive structural determination of protein nanocrystals and single molecules that are too small and radiation-sensitive for conventional x-ray diffraction. However the electronic form factor may be modified during the ultrashort x-ray pulse due to photoionization and electron cascade caused by the intense x-ray pulse. For general x-ray imaging techniques, the minimization of the effects of radiation damage is of major concern to ensure reliable reconstruction of molecular structure. Here in this paper, we show that radiation damage free diffraction can be achieved with atomic spatial resolution by using x-ray parametric down-conversion and ghostmore » diffraction with entangled photons of x-ray and optical frequencies. We show that the formation of the diffraction patterns satisfies a condition analogous to the Bragg equation, with a resolution that can be as fine as the crystal lattice length scale of several Ångstrom. Since the samples are illuminated by low energy optical photons, they can be free of radiation damage.« less

Synchrotron Radiation X-ray Diffraction Techniques Applied to Insect Flight Muscle.

PubMed

Iwamoto, Hiroyuki

2018-06-13

X-ray fiber diffraction is a powerful tool used for investigating the molecular structure of muscle and its dynamics during contraction. This technique has been successfully applied not only to skeletal and cardiac muscles of vertebrates but also to insect flight muscle. Generally, insect flight muscle has a highly ordered structure and is often capable of high-frequency oscillations. The X-ray diffraction studies on muscle have been accelerated by the advent of 3rd-generation synchrotron radiation facilities, which can generate brilliant and highly oriented X-ray beams. This review focuses on some of the novel experiments done on insect flight muscle by using synchrotron radiation X-rays. These include diffraction recordings from single myofibrils within a flight muscle fiber by using X-ray microbeams and high-speed diffraction recordings from the flight muscle during the wing-beat of live insects. These experiments have provided information about the molecular structure and dynamic function of flight muscle in unprecedented detail. Future directions of X-ray diffraction studies on muscle are also discussed.

Constituents of Musa x paradisiaca cultivar with the potential to induce the phase II enzyme, quinone reductase.

PubMed

Jang, Dae Sik; Park, Eun Jung; Hawthorne, Michael E; Vigo, Jose Schunke; Graham, James G; Cabieses, Fernando; Santarsiero, Bernard D; Mesecar, Andrew D; Fong, Harry H S; Mehta, Rajendra G; Pezzuto, John M; Kinghorn, A Douglas

2002-10-23

A new bicyclic diarylheptanoid, rel-(3S,4aR,10bR)-8-hydroxy-3-(4-hydroxyphenyl)-9-methoxy-4a,5,6,10b-tetrahydro-3H-naphtho[2,1-b]pyran (1), as well as four known compounds, 1,2-dihydro-1,2,3-trihydroxy-9-(4-methoxyphenyl)phenalene (2), hydroxyanigorufone (3), 2-(4-hydroxyphenyl)naphthalic anhydride (4), and 1,7-bis(4-hydroxyphenyl)hepta-4(E),6(E)-dien-3-one (5), were isolated from an ethyl acetate-soluble fraction of the methanol extract of the fruits of Musa x paradisiaca cultivar, using a bioassay based on the induction of quinone reductase (QR) in cultured Hepa1c1c7 mouse hepatoma cells to monitor chromatographic fractionation. The structure and relative stereochemistry of compound 1 were elucidated unambiguously by one- and two-dimensional NMR experiments ((1)H NMR, (13)C NMR, DEPT, COSY, HMQC, HMBC, and NOESY) and single-crystal X-ray diffraction analysis. Isolates 1-5 were evaluated for their potential cancer chemopreventive properties utilizing an in vitro assay to determine quinone reductase induction and a mouse mammary organ culture assay.

Combining experiment and optical simulation in coherent X-ray nanobeam characterization of Si/SiGe semiconductor heterostructures

DOE PAGES

Tilka, J. A.; Park, J.; Ahn, Y.; ...

2016-07-06

Here, the highly coherent and tightly focused x-ray beams produced by hard x-ray light sources enable the nanoscale characterization of the structure of electronic materials but are accompanied by significant challenges in the interpretation of diffraction and scattering patterns. X-ray nanobeams exhibit optical coherence combined with a large angular divergence introduced by the x-ray focusing optics. The scattering of nanofocused x-ray beams from intricate semiconductor heterostructures produces a complex distribution of scattered intensity. We report here an extension of coherent xray optical simulations of convergent x-ray beam diffraction patterns to arbitrary x-ray incident angles to allow the nanobeam diffraction patternsmore » of complex heterostructures to be simulated faithfully. These methods are used to extract the misorientation of lattice planes and the strain of individual layers from synchrotron x-ray nanobeam diffraction patterns of Si/SiGe heterostructures relevant to applications in quantum electronic devices. The systematic interpretation of nanobeam diffraction patterns from semiconductor heterostructures presents a new opportunity in characterizing and ultimately designing electronic materials.« less

A theoretical insight for solvent effect on myoglobin assay of W(CO)4L2 type novel complexes with DFT/TDDFT

NASA Astrophysics Data System (ADS)

Üstün, Elvan; Demi˙r, Serpil; Coşkun, Feyzullah; Kaloğlu, Murat; Şahi˙n, Onur; Büyükgüngör, Orhan; Özdemi˙r, İsmail

2016-11-01

Novel tetracarbonyl complexes of type W(CO)4L2 (L: 4-chlorobenzylimidazoline; 4-methylbenzylimidazoline; 3,5-dimethylbenzylimidazoline; 2,4,6-trimethylbenzylimidazoline; 2,3,5,6- tetramethylbenzylimidazoline) were synthesized. Then newly synthesized novel compounds were characterized by IR, 1H NMR, 13C NMR and LC-MS. The characterizations of two of the complexes have also been confirmed with single crystal X-Ray diffraction and DFT optimization results of these complexes have been compared with single crystal results. We have investigated the solvent effect on the structure and metal-to-ligand charge transfer (MLCT) transitions with DFT/TDDFT calculations with ORCA package program with BP86 functional.

NMR, symmetry elements, structure and phase transitions in the argyrodite family

NASA Astrophysics Data System (ADS)

Gaudin, E.; Taulelle, F.; Boucher, F.; Evain, M.

1998-02-01

Cu7PSe6 belongs to a family of structures known as the argyrodites. It undergoes two phases transitions. The high temperature phase has been determined by X-ray diffraction. It has a Foverline{4}3m space group. Medium temperature phases have been refined using a non-harmonic technique and the space group proposed is P213. The low temperature phase had an apparent space group of Foverline{4}3m also. Use of X-ray diffraction and NMR together has allowed to determine the space groups of all phases as being respectively Foverline{4}3m, P213 and Pmn21. Positioning of disordered coppers in the structure is therefore possible and the structure can be described by connex polyhedra of PSe3-4 and SeCux-2_x. The phase transitions can be understood by an ordered motion of SeCux-2x polyhedra. If these polyhedra set in motion independently two transitions are to be observed, if they are coupled only one is observed. Cu7PSe6 appartient à une famille de composés connus sous le nom d'argyrodites. Cu7PSe6 possède deux transitions de phase. La structure de haute température a été déterminée par diffraction des rayons X. Elle se décrit par le groupe d'espace Foverline{4}3m. La phase de moyenne température a été raffinée en utilisant une technique non-harmonique et le groupe d'espace proposé est P213. La phase de basse température possède également un groupe d'espace apparent Foverline{4}3m. En utilisant ensemble la diffraction des rayons X et la RMN, il a été possible de déterminer les groupes d'espace de toutes les phases comme étant respectivement Foverline{4}3m, P213 et Pmn21. Placer les atomes de cuivre, désordonnés, dans la structure devient alors possible et la structure peut se décrire comme un ensemble de polyèdres connexes de PSe3-4 et SeCux-2_x. Les transitions de phases se décrivent alors comme des mouvements ordonnés des polyèdres SeCux-2_x. Si ces polyèdres se mettent en mouvement indépendamment, deux transitions de phases sont attendues, si leur mise en mouvement est couplée, une seule est observée.

Fabrication and testing of a newly designed slit system for depth-resolved X-ray diffraction measurements

DOE PAGES

Sinsheimer, John; Bouet, Nathalie; Ghose, Sanjit; ...

2016-10-06

A new system of slits called `spiderweb slits' have been developed for depth-resolved powder or polycrystalline X-ray diffraction measurements. The slits act on diffracted X-rays to select a particular gauge volume of sample, while absorbing diffracted X-rays from outside of this volume. Although the slit geometry is to some extent similar to that of previously developed conical slits or spiral slits, this new design has advantages over the previous ones in use for complex heterogeneous materials and in situ and operando diffraction measurements. For example, the slits can measure a majority of any diffraction cone for any polycrystalline material, overmore » a continuous range of diffraction angles, and work for X-ray energies of tens to hundreds of kiloelectronvolts. In addition, the design is generated and optimized using ray-tracing simulations, and fabricated through laser micromachining. The first prototype was successfully tested at the X17A beamline at the National Synchrotron Light Source, and shows similar performance to simulations, demonstrating gauge volume selection for standard powders, for all diffraction peaks over angles of 2–10°. A similar, but improved, design will be implemented at the X-ray Powder Diffraction beamline at the National Synchrotron Light Source II.« less

Atomistic characterisation of Li+ mobility and conductivity in Li(7-x)PS(6-x)Ix argyrodites from molecular dynamics simulations, solid-state NMR, and impedance spectroscopy.

PubMed

Pecher, Oliver; Kong, Shiao-Tong; Goebel, Thorsten; Nickel, Vera; Weichert, Katja; Reiner, Christof; Deiseroth, Hans-Jörg; Maier, Joachim; Haarmann, Frank; Zahn, Dirk

2010-07-26

The atomistic mechanisms of Li(+) ion mobility/conductivity in Li(7-x)PS(6-x)I(x) argyrodites are explored from both experimental and theoretical viewpoints. Ionic conductivity in the title compound is associated with a solid-solid phase transition, which was characterised by low-temperature differential scanning calorimetry, (7)Li and (127)I NMR investigations, impedance measurements and molecular dynamics simulations. The NMR signals of both isotopes are dominated by anisotropic interactions at low temperatures. A significant narrowing of the NMR signal indicates a motional averaging of the anisotropic interactions above 177+/-2 K. The activation energy to ionic conductivity was assessed from both impedance spectroscopy and molecular dynamics simulations. The latter revealed that a series of interstitial sites become accessible to the Li(+) ions, whilst the remaining ions stay at their respective sites in the argyrodite lattice. The interstitial positions each correspond to the centres of tetrahedra of S/I atoms, and differ only in terms of their common corners, edges, or faces with adjacent PS(4) tetrahedra. From connectivity analyses and free-energy rankings, a specific tetrahedron is identified as the key restriction to ionic conductivity, and is clearly differentiated from local mobility, which follows a different mechanism with much lower activation energy. Interpolation of the lattice parameters as derived from X-ray diffraction experiments indicates a homogeneity range for Li(7-x)PS(6-x)I(x) with 0.97 < or = x < or = 1.00. Within this range, molecular dynamics simulations predict Li(+) conductivity at ambient conditions to vary considerably.

Solution and Solid State Nuclear Magnetic Resonance Spectroscopic Characterization of Efavirenz.

PubMed

Sousa, Eduardo Gomes Rodrigues de; Carvalho, Erika Martins de; San Gil, Rosane Aguiar da Silva; Santos, Tereza Cristina Dos; Borré, Leandro Bandeira; Santos-Filho, Osvaldo Andrade; Ellena, Javier

2016-09-01

Samples of efavirenz (EFZ) were evaluated to investigate the influence of the micronization process on EFZ stability. A combination of X-ray diffraction, thermal analysis, FTIR, observations of isotropic chemical shifts of (1)H in distinct solvents, their temperature dependence and spin-lattice relaxation time constants (T1), solution (1D and 2D) (13)C nuclear magnetic resonance (NMR), and solid-state (13)C NMR (CPMAS NMR) provides valuable structural information and structural elucidation of micronized EFZ and heptane-recrystallized polymorphs (EFZ/HEPT). This study revealed that the micronization process did not affect the EFZ crystalline structure. It was observed that the structure of EFZ/HEPT is in the same form as that obtained from ethyl acetate/hexane, as shown in the literature. A comparison of the solid-state NMR spectra revealed discrepancies regarding the assignments of some carbons published in the literature that have been resolved. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Synthesis, spectroscopic and theoretical studies of ethyl (2E)-3-amino-2-({[(4-benzoyl-1,5-diphenyl-1H-pyrazol-3-yl)carbonyl]amino}carbonothioyl)but-2-enoate butanol solvate

NASA Astrophysics Data System (ADS)

Koca, İrfan; Sert, Yusuf; Gümüş, Mehmet; Kani, İbrahim; Çırak, Çağrı

2014-01-01

We have synthesized ethyl (2E)-3-amino-2-({[(4-benzoyl-1,5-diphenyl-1H-pyrazol-3-yl)carbonyl]amino}carbonothioyl)but-2-enoate (2) by the reaction of 4-benzoyl-1,5-diphenyl-1H-pyrazole-3-carbonyl chloride (1), ammonium thiocyanate and ethyl 3-aminobut-2-enoate and then characterized by elemental analyses, IR, Raman, 1H NMR, 13C NMR and X-ray diffraction methods. The experimental and theoretical vibrational spectra of 2 were investigated. The experimental FT-IR (4000-400 cm-1) and Laser-Raman spectra (4000-100 cm-1) of the molecule in the solid phase were recorded. Theoretical vibrational frequencies and geometric parameters (bond lengths, bond angles) were calculated using Ab Initio Hartree Fock (HF), Density Functional Theory (B3LYP) methods with 6-311++G(d,p) basis set by Gaussian 09W program. The computed values of frequencies are scaled using a suitable scale factor to yield good coherence with the observed values. The assignments of the vibrational frequencies were performed by potential energy distribution (PED) analysis by using VEDA 4 program. The theoretical optimized geometric parameters and vibrational frequencies were compared with the corresponding experimental X-ray diffraction data, and they were seen to be in a good agreement with each other. Also, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies were calculated.

Clathrochelates meet phosphorus. New thio- and phosphorylation reactions of an iron(II) dichloroclathrochelate precursor and preparation of its first phosphorus(III)-containing macrobicyclic derivative.

PubMed

Artyushin, Oleg I; Matveeva, Ekaterina V; Vologzhanina, Anna V; Voloshin, Yan Z

2016-03-28

Phosphorylation reactions of an iron(II) dichloroclathrochelate FeBd2(Cl2Gm)(BF)2 (where Bd(2-) and Cl2Gm(2-) are α-benzildioxime and dichloroglyoxime dianions, respectively) with diphenylphosphine oxide and diethyl thiophosphite were performed under phase-transfer conditions. In the case of diethyl thiophosphite as a P-nucleophile, the best yields were obtained in the dichloromethane-50% NaOH aqueous solution-5 mol% triethylbenzylammonium chloride (TEBAC) system. The use of different molar ratios of a macrobicycle precursor and this thiophosphorylating agent allowed us to obtain both the mono- and the diphosphorylated cage complexes. Nucleophilic substitution with diphenylphosphine oxide was performed in the K2CO3-acetonitrile-5 mol% TEBAC system, giving only the corresponding monophosphorylated iron(II) complex in high yield even in the presence of an excess of this P-nucleophile. The phosphorus(v)-containing clathrochelate product was reduced with an excess of silicoform to give an iron(II) macrobicycle with an inherent diphenylphosphine group in an almost quantitative yield, which was then characterized by (31)P{(1)H} NMR and single-crystal X-ray diffraction; it easily undergoes re-oxidation to the initial clathrochelate. The synthesized phosphorus(v)-containing cage complexes were characterized using elemental analysis, MALDI-TOF mass, IR, UV-Vis, (1)H, (11)B, (13)C{(1)H}, (19)F{(1)H} and (31)P{(1)H} NMR spectra, and by single-crystal X-ray diffraction.

Cl⋯N weak interactions. Conformational analysis of imidazol-2-ylum heterocycles bearing N-β-chloroethyl and N-vinyl pendant groups

NASA Astrophysics Data System (ADS)

Rodríguez-López, Germán; Montes-Tolentino, Pedro; Sánchez-Ruiz, Sonia; Villaseñor-Granados, Tayde Osvaldo; Flores-Parra, Angelina

2017-11-01

Enantiomerically pure and racemic mixtures of β-chloroethylamines hydrochlorides with one and two stereogenic centres were used to synthesise 1,4-dialkyl-1,3-diimines, which in turn gave place to a series of imidazolium chlorides and tetraphenylborates bearing pendant N-β-chloroethyl substituents (sbnd CHEt-CH2Cl; sbnd CHMe-CHPhCl). Stereoselective dehydrochlorination of imidazolium compounds afforded in good yield the corresponding heterocycles bearing N-vinyl groups (-CEt=CH2; -CMe=CHPh). The volume of the N-substituents provides a steric screening of the cationic ring. The structure of the new compounds was determined by IR, mass spectra, NMR and X-ray diffraction analyses as well as DFT calculations of the optimized geometries. Uncommon stabilising intramolecular Cl⋯N weak interactions are described, together with H⋯Cl and H···π hydrogen bonds. The existence of the non-covalent weak intramolecular bonds was deduced from the X-ray diffraction analysis and confirmed by calculations of the electrostatic potential, electronic density distributions and the maps of the Laplacian functions of the electronic density.

Screening and structural elucidation of the zwitterionic cocrystal o-picolinic acid with p-nitro aniline

NASA Astrophysics Data System (ADS)

Mekala, R.; Jagdish, P.; Mathammal, R.; Sangeetha, K.

2017-04-01

The cocrystal was screened by solvent drop grinding method and the crystals were grown by slow evaporation method at ambient conditions. The cocrystal formation of o-picolinic acid with p-nitro aniline was initially analysed by powder X-ray diffraction. Further the structural properties of the grown crystal were confirmed by the single X-ray diffraction which indicates that the cocrystal were connected by the strong N+sbnd H-⋯O hydrogen bond interaction. The cell parameters of the grown crystal were a = 14.2144(5) Å, b = 5.7558(2) Å, c = 16.0539(6) Å. The functional groups were identified using Fourier transform infrared and Raman spectral analysis. The excitation and emission state of the sample was analysed by the UV-Visible and Fluorescence studies. The red emission was observed from the Fluorescence studies. NMR studies revealed the chemical shift of the cocrystal. Thermal stability and its melting behaviour were studied by TGA and DSC analytical techniques. Electrical behaviour was studied using the dielectric studies. The intermolecular charge transfer within the molecule were analysed using HOMO- LUMO plots.

Crystal growth, structural, optical, spectral and thermal studies of tris( L-phenylalanine) L-phenylalaninium nitrate: A new organic nonlinear optical material

NASA Astrophysics Data System (ADS)

Prakash, M.; Geetha, D.; Lydia Caroline, M.

2011-10-01

Tris( L-phenylalanine) L-phenylalaninium nitrate, C 9H 12NO 2+·NO 3-·3C 9H 11NO 2 (TPLPN), a new organic nonlinear optical material was grown from aqueous solution by slow evaporation solution growth at room temperature. The grown crystals were subjected to powder X-ray diffraction and single crystal X-ray diffraction studies to confirm the crystalline nature and crystal structure. The modes of vibration of different molecular groups present in TPLPN have been identified by FTIR spectral analysis. The presence of hydrogen and carbon in the grown crystal were confirmed by using proton and carbon nuclear magnetic resonance (NMR) spectral analyses. The optical transmission spectral study establishes good transmitting ability of the crystal in the entire visible region. The thermogravimetric (TG) and differential thermal analyses (DTA) were carried out to understand the thermal stability of the sample. The nonlinear optical property of the compound observed using Kurtz powder second harmonic generation test assets the suitability of the grown material for the frequency conversion of laser radiation of Nd:YAG.

Thermal degradation behavior and X-ray diffraction studies of chitosan based polyurethane bio-nanocomposites using different diisocyanates.

PubMed

Javaid, Muhammad Asif; Rizwan, Muhammad; Khera, Rasheed Ahmad; Zia, Khalid Mahmood; Saito, Kei; Zuber, Muhammad; Iqbal, Javed; Langer, Peter

2018-05-29

Five different samples of chitosan based polyurethane bio-nanocomposites (PUBNCs) were synthesized by step growth polymerization technique. Five different diisocyanates were used by keeping hydroxyl terminated polybutadiene (HTPB)/1,4-butane diol (1,4-BDO)/chitosan (CS) and montmorillonite (MMT) clay ratios constant (PUR1-PUR5). For comparative studies, PUR-6 was prepared without CS and clay components. Molecular characterizations of polyurethane (PU) films were carried out by FTIR and NMR which was found to have confirmatory evidence of the proposed structures. X-ray diffraction angles (2θ), d-spacing and intensities of chitosan based samples (PUR1-PUR5) and PUR-6 indicated that crystalline behavior of PUBNCs is influenced by varying diisocyanate structures. TGA/DTA results revealed that chitosan increased thermal stability of PU samples; it also enhanced the mechanical strength and decreased the glass transition temperature (T g ) of all the samples. Based on the above mentioned facts this study suggests the best usage of PUs according to the operational and environmental conditions. Copyright © 2018 Elsevier B.V. All rights reserved.

Structure and vibrational spectra of melaminium bis(trifluoroacetate) trihydrate: FT-IR, FT-Raman and quantum chemical calculations

NASA Astrophysics Data System (ADS)

Sangeetha, V.; Govindarajan, M.; Kanagathara, N.; Marchewka, M. K.; Gunasekaran, S.; Anbalagan, G.

Melaminium bis(trifluoroacetate) trihydrate (MTFA), an organic material has been synthesized and single crystals of MTFA have been grown by the slow solvent evaporation method at room temperature. X-ray powder diffraction analysis confirms that MTFA crystal belongs to the monoclinic system with space group P2/c. The molecular geometry, vibrational frequencies and intensity of the vibrational bands have been interpreted with the aid of structure optimization based on density functional theory (DFT) B3LYP method with 6-311G(d,p) and 6-311++G(d,p) basis sets. The X-ray diffraction data have been compared with the data of optimized molecular structure. The theoretical results show that the crystal structure can be reproduced by optimized geometry and the vibrational frequencies show good agreement with the experimental values. The nuclear magnetic resonance (NMR) chemical shift of the molecule has been calculated by the gauge independent atomic orbital (GIAO) method and compared with experimental results. HOMO-LUMO, and other related molecular and electronic properties are calculated. The Mulliken and NBO charges have also been calculated and interpreted.

Dynamical scattering in coherent hard x-ray nanobeam Bragg diffraction

NASA Astrophysics Data System (ADS)

Pateras, A.; Park, J.; Ahn, Y.; Tilka, J. A.; Holt, M. V.; Kim, H.; Mawst, L. J.; Evans, P. G.

2018-06-01

Unique intensity features arising from dynamical diffraction arise in coherent x-ray nanobeam diffraction patterns of crystals having thicknesses larger than the x-ray extinction depth or exhibiting combinations of nanoscale and mesoscale features. We demonstrate that dynamical scattering effects can be accurately predicted using an optical model combined with the Darwin theory of dynamical x-ray diffraction. The model includes the highly divergent coherent x-ray nanobeams produced by Fresnel zone plate focusing optics and accounts for primary extinction, multiple scattering, and absorption. The simulation accurately reproduces the dynamical scattering features of experimental diffraction patterns acquired from a GaAs/AlGaAs epitaxial heterostructure on a GaAs (001) substrate.

Coherent x-ray diffraction imaging with nanofocused illumination.

PubMed

Schroer, C G; Boye, P; Feldkamp, J M; Patommel, J; Schropp, A; Schwab, A; Stephan, S; Burghammer, M; Schöder, S; Riekel, C

2008-08-29

Coherent x-ray diffraction imaging is an x-ray microscopy technique with the potential of reaching spatial resolutions well beyond the diffraction limits of x-ray microscopes based on optics. However, the available coherent dose at modern x-ray sources is limited, setting practical bounds on the spatial resolution of the technique. By focusing the available coherent flux onto the sample, the spatial resolution can be improved for radiation-hard specimens. A small gold particle (size <100 nm) was illuminated with a hard x-ray nanobeam (E=15.25 keV, beam dimensions approximately 100 x 100 nm2) and is reconstructed from its coherent diffraction pattern. A resolution of about 5 nm is achieved in 600 s exposure time.

DynAMITe: a prototype large area CMOS APS for breast cancer diagnosis using x-ray diffraction measurements

NASA Astrophysics Data System (ADS)

Konstantinidis, A.; Anaxagoras, T.; Esposito, M.; Allinson, N.; Speller, R.

2012-03-01

X-ray diffraction studies are used to identify specific materials. Several laboratory-based x-ray diffraction studies were made for breast cancer diagnosis. Ideally a large area, low noise, linear and wide dynamic range digital x-ray detector is required to perform x-ray diffraction measurements. Recently, digital detectors based on Complementary Metal-Oxide- Semiconductor (CMOS) Active Pixel Sensor (APS) technology have been used in x-ray diffraction studies. Two APS detectors, namely Vanilla and Large Area Sensor (LAS), were developed by the Multidimensional Integrated Intelligent Imaging (MI-3) consortium to cover a range of scientific applications including x-ray diffraction. The MI-3 Plus consortium developed a novel large area APS, named as Dynamically Adjustable Medical Imaging Technology (DynAMITe), to combine the key characteristics of Vanilla and LAS with a number of extra features. The active area (12.8 × 13.1 cm2) of DynaMITe offers the ability of angle dispersive x-ray diffraction (ADXRD). The current study demonstrates the feasibility of using DynaMITe for breast cancer diagnosis by identifying six breast-equivalent plastics. Further work will be done to optimize the system in order to perform ADXRD for identification of suspicious areas of breast tissue following a conventional mammogram taken with the same sensor.

Resolution enhancement in coherent x-ray diffraction imaging by overcoming instrumental noise.

PubMed

Kim, Chan; Kim, Yoonhee; Song, Changyong; Kim, Sang Soo; Kim, Sunam; Kang, Hyon Chol; Hwu, Yeukuang; Tsuei, Ku-Ding; Liang, Keng San; Noh, Do Young

2014-11-17

We report that reference objects, strong scatterers neighboring weak phase objects, enhance the phase retrieval and spatial resolution in coherent x-ray diffraction imaging (CDI). A CDI experiment with Au nano-particles exhibited that the reference objects amplified the signal-to-noise ratio in the diffraction intensity at large diffraction angles, which significantly enhanced the image resolution. The interference between the diffracted x-ray from reference objects and a specimen also improved the retrieval of the phase of the diffraction signal. The enhancement was applied to image NiO nano-particles and a mitochondrion and confirmed in a simulation with a bacteria phantom. We expect that the proposed method will be of great help in imaging weakly scattering soft matters using coherent x-ray sources including x-ray free electron lasers.

Solid state characterization and crystal structure from X-ray powder diffraction of two polymorphic forms of ranitidine base.

PubMed

de Armas, Héctor Novoa; Peeters, Oswald M; Blaton, Norbert; Van Gyseghem, Elke; Martens, Johan; Van Haele, Gerrit; Van Den Mooter, Guy

2009-01-01

Ranitidine hydrochloride (RAN-HCl), a known anti-ulcer drug, is the product of reaction between HCl and ranitidine base (RAN-B). RAN-HCl has been extensively studied; however this is not the case of the RAN-B. The solid state characterization of RAN-B polymorphs has been carried out using different analytical techniques (microscopy, thermal analysis, Fourier transform infrared spectrometry in the attenuated total reflection mode, (13)C-CPMAS-NMR spectroscopy and X-ray powder diffraction). The crystal structures of RAN-B form I and form II have been determined using conventional X-ray powder diffraction in combination with simulated annealing and whole profile pattern matching, and refined using rigid-body Rietveld refinement. RAN-B form I is a monoclinic polymorph with cell parameters: a = 7.317(2), b = 9.021(2), c = 25.098(6) A, beta = 95.690(1) degrees and space group P2(1)/c. The form II is orthorhombic: a = 31.252(4), b = 13.052(2), c = 8.0892(11) A with space group Pbca. In RAN-B polymorphs, the nitro group is involved in a strong intramolecular hydrogen bond responsible for the existence of a Z configuration in the enamine portion of the molecules. A tail to tail packing motif can be denoted via intermolecular hydrogen bonds. The crystal structures of RAN-B forms are compared to those of RAN-HCl polymorphs. RAN-B polymorphs are monotropic polymorphic pairs. (c) 2008 Wiley-Liss, Inc. and the American Pharmacists Association

Fabrication and testing of a newly designed slit system for depth-resolved X-ray diffraction measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sinsheimer, John; Bouet, Nathalie; Ghose, Sanjit

2016-10-06

A new system of slits called `spiderweb slits' have been developed for depth-resolved powder or polycrystalline X-ray diffraction measurements. The slits act on diffracted X-rays to select a particular gauge volume of sample, while absorbing diffracted X-rays from outside of this volume. Although the slit geometry is to some extent similar to that of previously developed conical slits or spiral slits, this new design has advantages over the previous ones in use for complex heterogeneous materials andin situandoperandodiffraction measurements. For example, the slits can measure a majority of any diffraction cone for any polycrystalline material, over a continuous range ofmore » diffraction angles, and work for X-ray energies of tens to hundreds of kiloelectronvolts. The design is generated and optimized using ray-tracing simulations, and fabricated through laser micromachining. The first prototype was successfully tested at the X17A beamline at the National Synchrotron Light Source, and shows similar performance to simulations, demonstrating gauge volume selection for standard powders, for all diffraction peaks over angles of 2–10°. A similar, but improved, design will be implemented at the X-ray Powder Diffraction beamline at the National Synchrotron Light Source II.« less

Local terahertz field enhancement for time-resolved x-ray diffraction

DOE PAGES

Kozina, M.; Pancaldi, M.; Bernhard, C.; ...

2017-02-20

We report local field strength enhancement of single-cycle terahertz (THz) pulses in an ultrafast time-resolved x-ray diffraction experiment. We show that patterning the sample with gold microstructures increases the THz field without changing the THz pulse shape or drastically affecting the quality of the x-ray diffraction pattern. Lastly, we find a five-fold increase in THz-induced x-ray diffraction intensity change in the presence of microstructures on a SrTiO 3 thin-film sample.

Local terahertz field enhancement for time-resolved x-ray diffraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kozina, M.; Pancaldi, M.; Bernhard, C.

We report local field strength enhancement of single-cycle terahertz (THz) pulses in an ultrafast time-resolved x-ray diffraction experiment. We show that patterning the sample with gold microstructures increases the THz field without changing the THz pulse shape or drastically affecting the quality of the x-ray diffraction pattern. Lastly, we find a five-fold increase in THz-induced x-ray diffraction intensity change in the presence of microstructures on a SrTiO 3 thin-film sample.

Thermal x-ray diffraction and near-field phase contrast imaging

NASA Astrophysics Data System (ADS)

Li, Zheng; Classen, Anton; Peng, Tao; Medvedev, Nikita; Wang, Fenglin; Chapman, Henry N.; Shih, Yanhua

2017-10-01

Using higher-order coherence of thermal light sources, the resolution power of standard x-ray imaging techniques can be enhanced. In this work, we applied the higher-order measurement to far-field x-ray diffraction and near-field phase contrast imaging (PCI), in order to achieve superresolution in x-ray diffraction and obtain enhanced intensity contrast in PCI. The cost of implementing such schemes is minimal compared to the methods that achieve similar effects by using entangled x-ray photon pairs.

Thermal x-ray diffraction and near-field phase contrast imaging

DOE PAGES

Li, Zheng; Classen, Anton; Peng, Tao; ...

2017-12-27

Using higher-order coherence of thermal light sources, the resolution power of standard x-ray imaging techniques can be enhanced. Here in this work, we applied the higher-order measurement to far-field x-ray diffraction and near-field phase contrast imaging (PCI), in order to achieve superresolution in x-ray diffraction and obtain enhanced intensity contrast in PCI. The cost of implementing such schemes is minimal compared to the methods that achieve similar effects by using entangled x-ray photon pairs.

An image focusing means by using an opaque object to diffract x-rays

DOEpatents

Sommargren, Gary E.; Weaver, H. Joseph

1991-01-01

The invention provides a method and apparatus for focusing and imaging x-rays. An opaque sphere is used as a diffractive imaging element to diffract x-rays from an object so that the divergent x-ray wavefronts are transformed into convergent wavefronts and are brought to focus to form an image of the object with a large depth of field.

Synthesis, single crystal X-ray, spectroscopic (FT-IR, UV-vis, fluorescence, 1H &13C NMR), computational (DFT/B3LYP) studies of some imidazole based picrates

NASA Astrophysics Data System (ADS)

Arockia doss, M.; Rajarajan, G.; Thanikachalam, V.; Selvanayagam, S.; Sridhar, B.

2018-04-01

2,4,5-triphenyl-1H-imidazol-3-ium picrate (1), 2-(4-fluorophenyl)-4,5-diphenyl-1H-imidazol-3-ium picrate (2), 2-(4-methylphenyl)-4,5-diphenyl-1H-imidazol-3-ium picrate (3) were synthesised. These compounds 1-3 were characterized by elemental, FT-IR, 1H NMR and 13C NMR analyses. The structure of compound 3 was further confirmed by single crystal X-ray diffraction. The studies reveal that the molecule is associated with weak Nsbnd H⋯O and Csbnd H⋯N and van der Waals interactions which are responsible for the formation and strengthening of supramolecular assembly. The nature of the interactions and their importance are explored using the Hirshfeld surface method. The physicochemical properties of the compounds 1-3 were evaluated by UV-vis spectroscopy, fluorescence spectroscopy, and thermogravimetric analysis. According to thermal data the salts possess excellent thermal stabilities with decomposition temperatures ranging from 220 to 280 °C. Second-harmonic generation (SHG) results exposed that the picrates 1-3 were about 1.13-1.50 times greater than potassium dihydrogen phosphate (KDP). Here we also used Density functional theory (DFT) calculations in order to investigate the opto-electronic properties. The obtained theoretical results validate with available experimental data.

Soft X-Ray Diffraction Microscopy of a Frozen Hydrated Yeast Cell

DOE PAGES

Huang, Xiaojing; Nelson, Johanna; Kirz, Janos; ...

2009-11-01

We report the first image of an intact, frozen hydrated eukaryotic cell using x-ray diffraction microscopy, or coherent x-ray diffraction imaging. By plunge freezing the specimen in liquid ethane and maintaining it below -170 °C, artifacts due to dehydration, ice crystallization, and radiation damage are greatly reduced. In this example, coherent diffraction data using 520 eV x rays were recorded and reconstructed to reveal a budding yeast cell at a resolution better than 25 nm. This demonstration represents an important step towards high resolution imaging of cells in their natural, hydrated state, without limitations imposed by x-ray optics.

Thermal behavior of potato starch and water-vaporization behavior of its paste controlled with amino acid and peptide-rich food materials.

PubMed

Sakauchi, Satoshi; Hattori, Makoto; Yoshida, Tadashi; Yagishita, Takahiro; Ito, Koichi; Akemitsu, Shin-Ichi; Takahashi, Koji

2010-03-01

The particular effect of 4 kinds of amino acid and peptide-rich food material (APRM) containing different charged amino acid contents on the gelatinization and retrogradation behavior of potato starch granules and on the water-vaporization behavior was analyzed by differential scanning calorimetry, rapid viscoanalysis, x-ray diffractometry, thermal gravimetry-differential thermal analysis, and pulsed NMR. APRM with a high-charged amino acid content produced unique gelatinization and retrogradation behavior in terms of an elevated gelatinization temperature, reduced viscosity, higher setback, and lower retrograded starch melting enthalpy. The recovered x-ray diffraction intensity decreased with increasing charged amino acid content. APRM with high-charged amino acid content could provide an improved paste having easy vaporization of external water in the swollen starch granules due to the reduced swelling.

Revisiting 63Cu NMR evidence for charge order in superconducting La1.885Sr0.115CuO4

NASA Astrophysics Data System (ADS)

Imai, T.; Takahashi, S. K.; Arsenault, A.; Acton, A. W.; Lee, D.; He, W.; Lee, Y. S.; Fujita, M.

2017-12-01

The presence of charge and spin stripe order in the La2CuO4 -based family of superconductors continues to lead to new insight on the unusual ground-state properties of high-Tc cuprates. Soon after the discovery of charge stripe order at Tcharge≃65 K in Nd3 + co-doped La1.48Nd0.4Sr0.12CuO4 (Tc≃6 K) [Tranquada et al., Nature (London) 375, 561 (1995), 10.1038/375561a0], Hunt et al. demonstrated that La1.48Nd0.4Sr0.12CuO4 and superconducting La2 -xSrxCuO4 with x ˜1 /8 (Tc≃30 K) share nearly identical NMR anomalies near Tcharge of the former [Phys. Rev. Lett. 82, 4300 (1999), 10.1103/PhysRevLett.82.4300]. Their inevitable conclusion that La1.885Sr0.115CuO4 also undergoes charge order at a comparable temperature became controversial, because diffraction measurements at the time were unable to detect Bragg peaks associated with charge order. Recent advances in x-ray diffraction techniques finally led to definitive confirmations of the charge order Bragg peaks in La1.885Sr0.115CuO4 with an onset at as high as Tcharge≃80 K. Meanwhile, improved instrumental technology has enabled routine NMR measurements that were not feasible two decades ago. Motivated by these new developments, we revisit the charge order transition of a La1.885Sr0.115CuO4 single crystal based on 63Cu NMR techniques. We demonstrate that 63Cu NMR properties of the nuclear spin Iz=-1/2 to +1/2 central transition below Tcharge exhibit unprecedentedly strong dependence on the measurement time scale set by the separation time τ between the 90∘ and 180∘ radio-frequency pulses; a new kind of anomalous, very broad winglike 63Cu NMR signals gradually emerge below Tcharge only for extremely short τ ≲4 μ s , while the spectral weight INormal of the normal NMR signals is progressively wiped out. The NMR linewidth and relaxation rates depend strongly on τ below Tcharge, and their enhancement in the charge ordered state indicates that charge order turns on strong but inhomogeneous growth of Cu spin-spin correlations.

Application of focused-beam flat-sample method to synchrotron powder X-ray diffraction with anomalous scattering effect

NASA Astrophysics Data System (ADS)

Tanaka, M.; Katsuya, Y.; Matsushita, Y.

2013-03-01

The focused-beam flat-sample method (FFM), which is a method for high-resolution and rapid synchrotron X-ray powder diffraction measurements by combination of beam focusing optics, a flat shape sample and an area detector, was applied for diffraction experiments with anomalous scattering effect. The advantages of FFM for anomalous diffraction were absorption correction without approximation, rapid data collection by an area detector and good signal-to-noise ratio data by focusing optics. In the X-ray diffraction experiments of CoFe2O4 and Fe3O4 (By FFM) using X-rays near the Fe K absorption edge, the anomalous scattering effect between Fe/Co or Fe2+/Fe3+ can be clearly detected, due to the change of diffraction intensity. The change of observed diffraction intensity as the incident X-ray energy was consistent with the calculation. The FFM is expected to be a method for anomalous powder diffraction.

Rietveld analysis using powder diffraction data with anomalous scattering effect obtained by focused beam flat sample method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanaka, Masahiko, E-mail: masahiko@spring8.or.jp; Katsuya, Yoshio, E-mail: katsuya@spring8.or.jp; Sakata, Osami, E-mail: SAKATA.Osami@nims.go.jp

2016-07-27

Focused-beam flat-sample method (FFM) is a new trial for synchrotron powder diffraction method, which is a combination of beam focusing optics, flat shape powder sample and area detectors. The method has advantages for X-ray diffraction experiments applying anomalous scattering effect (anomalous diffraction), because of 1. Absorption correction without approximation, 2. High intensity X-rays of focused incident beams and high signal noise ratio of diffracted X-rays 3. Rapid data collection with area detectors. We applied the FFM to anomalous diffraction experiments and collected synchrotron X-ray powder diffraction data of CoFe{sub 2}O{sub 4} (inverse spinel structure) using X-rays near Fe K absorptionmore » edge, which can distinguish Co and Fe by anomalous scattering effect. We conducted Rietveld analyses with the obtained powder diffraction data and successfully determined the distribution of Co and Fe ions in CoFe{sub 2}O{sub 4} crystal structure.« less

Insights into the Effects of Zinc Doping on Structural Phase Transition of P2-Type Sodium Nickel Manganese Oxide Cathodes for High-Energy Sodium Ion Batteries.

PubMed

Wu, Xuehang; Xu, Gui-Liang; Zhong, Guiming; Gong, Zhengliang; McDonald, Matthew J; Zheng, Shiyao; Fu, Riqiang; Chen, Zonghai; Amine, Khalil; Yang, Yong

2016-08-31

P2-type sodium nickel manganese oxide-based cathode materials with higher energy densities are prime candidates for applications in rechargeable sodium ion batteries. A systematic study combining in situ high energy X-ray diffraction (HEXRD), ex situ X-ray absorption fine spectroscopy (XAFS), transmission electron microscopy (TEM), and solid-state nuclear magnetic resonance (SS-NMR) techniques was carried out to gain a deep insight into the structural evolution of P2-Na0.66Ni0.33-xZnxMn0.67O2 (x = 0, 0.07) during cycling. In situ HEXRD and ex situ TEM measurements indicate that an irreversible phase transition occurs upon sodium insertion-extraction of Na0.66Ni0.33Mn0.67O2. Zinc doping of this system results in a high structural reversibility. XAFS measurements indicate that both materials are almost completely dependent on the Ni(4+)/Ni(3+)/Ni(2+) redox couple to provide charge/discharge capacity. SS-NMR measurements indicate that both reversible and irreversible migration of transition metal ions into the sodium layer occurs in the material at the fully charged state. The irreversible migration of transition metal ions triggers a structural distortion, leading to the observed capacity and voltage fading. Our results allow a new understanding of the importance of improving the stability of transition metal layers.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalistratova, O. S., E-mail: Olga.Kalistratova@yandex.ru; Andreev, P. V.; Gushchin, A. V.

Bis[(2E)-3-(2-furyl)prop-2-enoato]triphenylantimony Ph{sub 3}Sb[O{sub 2}CCH=CH(C{sub 4}H{sub 3}O)]{sub 2} is obtained for the first time by the reaction of triphenylantimony, hydrogen peroxide, and 2-furylpropene acid. The X-ray diffraction data show that the central atom of antimony is coordinated in the shape of a distorted trigonal bipyramid. The base of the bipyramid is formed by carbon atoms of phenyl ligands, and the apical vertices are occupied by acid residues. The IR and NMR spectra agree with the composition and structure of the compound.

Synthesis, Crystal Structures and Properties of Ferrocenyl Bis-Amide Derivatives Yielded via the Ugi Four-Component Reaction.

PubMed

Zhao, Mei; Shao, Guang-Kui; Huang, Dan-Dan; Lv, Xue-Xin; Guo, Dian-Shun

2017-05-04

Ten ferrocenyl bis-amide derivatives were successfully synthesized via the Ugi four-component reaction by treating ferrocenecarboxylic acid with diverse aldehydes, amines, and isocyanides in methanol solution. Their chemical structures were fully characterized by IR, NMR, HR-MS, and X-ray diffraction analyses. They feature unique molecular morphologies and create a 14-membered ring motif in the centro-symmetric dimers generated in the solid state. Moreover, the electrochemical behavior of these ferrocenyl bis-amides was assessed by cyclic voltammetry.

In Situ Investigation of a Self-Accelerated Cocrystal Formation by Grinding Pyrazinamide with Oxalic Acid.

PubMed

Kulla, Hannes; Greiser, Sebastian; Benemann, Sigrid; Rademann, Klaus; Emmerling, Franziska

2016-07-14

A new cocrystal of pyrazinamide with oxalic acid was prepared mechanochemically and characterized by PXRD, Raman spectroscopy, solid-state NMR spectroscopy, DTA-TG, and SEM. Based on powder X-ray diffraction data the structure was solved. The formation pathway of the reaction was studied in situ using combined synchrotron PXRD and Raman spectroscopy. Using oxalic acid dihydrate the initially neat grinding turned into a rapid self-accelerated liquid-assisted grinding process by the release of crystallization water. Under these conditions, the cocrystal was formed directly within two minutes.

Configuration-specific synthesis of the facial and meridional isomers of tris(8-hydroxyquinolinate)aluminum (Alq3).

PubMed

Katakura, Ryo; Koide, Yoshihiro

2006-07-24

Treatment of AlO(OH) with 3 equiv of 8-hydroxyquinolinol in refluxing deionized water provided the meridional and facial isomers of tris(8-hydroxyquinolinate)aluminum (Alq3) with good yields as solid deposits after 1 and 90 h, respectively. X-ray diffraction and solid-state 13C NMR studies revealed that mer-Alq3 is formed in the early stage of the reaction and then gradually converts to fac-Alq3, which is thermodynamically less stable, although no existence of a catalyst substance is implied.

Direct synthesis of anti-1,3-diols through nonclassical reaction of aryl Grignard reagents with isopropenyl acetate.

PubMed

Jiao, Yinchun; Cao, Chenzhong; Zhou, Zaichun

2011-01-21

A series of symmetrical aromatic 1,3-diols were efficiently synthesized from substituted aryl Grignard reagents and isopropenyl acetate in a one-step reaction that formed anti products as the major species. Both experimental and theoretical studies suggested that the reaction involves the formation of a relatively stable intermediate E containing a six-membered ring from intermediate A. The stereoselectivity of the reactions and the molecular structure of the products were confirmed by NMR spectroscopy, X-ray diffraction, and gas chromatography.

Four new compounds from Imperata cylindrica.

PubMed

Liu, Xuan; Zhang, Bin-Feng; Yang, Li; Chou, Gui-Xin; Wang, Zheng-Tao

2014-04-01

Four new compounds, impecylone (1), deacetylimpecyloside (2), seguinoside K 4-methylether (3) and impecylenolide (4), were isolated from Imperata cylindrica along with two known compounds, impecyloside (5) and seguinoside K (6). Their structures were elucidated mainly by spectroscopic analyses including 1D- and 2D-NMR techniques, and the absolute configuration of 1 was confirmed by X-ray diffraction analysis. In calcium assay, the result indicated that compounds 1, 2, 4 and 5 cannot obviously inhibit the calcium peak value compared with the negative control, and suggested that the four compounds could not have anti-inflammatory activity.

Synthesis and crystal structure of (S, S, S, S)-N, N′-bis[N-(P-toluenesulfonamido)-1,2-diphenylethyl]ethylenediamine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, X.-G.; Zhang, T.; Hu, Y.-Y.

2013-12-15

(S, S, S, S)-N,N′-bis[N-(p-toluenesulfonamido)-1,2-diphenylethyl] ethylenediamine (C{sub 44}H{sub 46}N{sub 4}O{sub 4}S{sub 2}), has been synthesized and structurally characterized by elemental analysis, {sup 1}H-NMR, MS, IR and single-crystal X-ray diffraction. The title compound contains four chiral centers with C atoms in S configuration. Molecules are connected to one another by hydrogen bonds between sulfonamide nitrogen and sulfonyl oxygen to form chains alone a axis.

(±)-Uncarilins A and B, Dimeric Isoechinulin-Type Alkaloids from Uncaria rhynchophylla.

PubMed

Geng, Chang-An; Huang, Xiao-Yan; Ma, Yun-Bao; Hou, Bo; Li, Tian-Ze; Zhang, Xue-Mei; Chen, Ji-Jun

2017-04-28

(±)-Uncarilins A and B (1a/1b and 2a/2b), two pairs of unusual dimeric isoechinulin-type enantiomers with a symmetric four-membered core, were isolated from Uncaria rhynchophylla driven by LCMS-IT-TOF analyses. Their structures were elucidated by extensive 1D and 2D NMR spectra, X-ray diffraction, and ECD spectroscopic data. (-)-Uncarilin B (2a) showed activities on MT 1 and MT 2 receptors with agonistic rates of 11.26% and 52.44% at a concentration of 0.25 mM.

X-ray diffraction and spectroscopic study of wiluite: implications for the vesuvianite-group nomenclature

NASA Astrophysics Data System (ADS)

Panikorovskii, Taras L.; Mazur, Anton S.; Bazai, Ayya V.; Shilovskikh, Vladimir V.; Galuskin, Evgeny V.; Chukanov, Nikita V.; Rusakov, Vyacheslav S.; Zhukov, Yurii M.; Avdontseva, Evgenia Yu.; Aksenov, Sergey M.; Krivovichev, Sergey V.

2017-09-01

Two wiluite samples from the Wiluy River, Yakutia, Russia have been investigated by means of single-crystal and powder X-ray diffraction, electron microprobe analysis, 1H, 27Al, 11B, and 29Si magic-angle spinning nuclear magnetic resonance (MAS NMR), thermogravimetric analysis (DSC/TGA), X-ray photoelectron spectroscopy (XPS) at the Si2p, Ca2p, Al2p, Mg1s, B1s and Fe2p core levels, 57Fe Mössbauer spectroscopy, infrared (IR) spectroscopy and optical measurements. The crystal structures have been refined in the P4/ nnc space group [ a = 15.7027(3), c = 11.7008(3) Å, V = 2885.1(1) Å3 for 1 and a = 15.6950(2), c = 11.6787(4) Å, V = 2876.9(1) Å3 for 2] to R 1 = 0.022 and R 1 = 0.021, respectively. In the crystal structure of wiluite, five-coordinated Y1 site is predominantly occupied by Mg. IR spectra of wiluite substantially different from those of vesuvianite, in particular, by the presence of additional bands in the range 1080‒1415 cm-1, which correspond to symmetric B‒O stretching vibrations of the BO 3 3- and BO 4 5- groups. According to the MAS NMR data, tetrahedrally coordinated T1 site is occupied by B3+ with minor amounts of Al3+. The general formula of wiluite can be written as follows ( Z = 2): Ca19Mg(Al,Mg,Fe,Ti,Mn)12(B,Al,◻)5(Si2O7)4(SiO4)10(O,OH)9O2-3. The diversity of vesuvianite-group minerals is largely determined by the population of the Y1 sites. However, wiluite is characterized by the presence of additional T1 and T2 sites and should be considered as special among other vesuvianite-group minerals. The reasonability of subdivision of the wiluite subgroup within the vesuvianite group is discussed.

Real time neutron diffraction and NMR of the Empress II glass-ceramic system.

PubMed

O'Donnell, M D; Hill, R G; Karpukhina, N; Law, R V

2011-10-01

This study reports real time neutron diffraction on the Empress II glass-ceramic system. The commercial glass-ceramics was characterized by real time neutron diffraction, ³¹P and ²⁹Si solid-state MAS-NMR, DSC and XRD. On heating, the as-received glass ceramic contained lithium disilicate (Li₂Si₂O₅), which melted with increasing temperature. This was revealed by neutron diffraction which showed the Bragg peaks for this phase had disappeared by 958°C in agreement with thermal analysis. On cooling lithium metasilicate (Li₂SiO₃) started to form at around 916°C and a minor phase of cristobalite at around 852°C. The unit cell volume of both Li-silicate phases increased linearly with temperature at a rate of +17×10⁻³ ų.°C⁻¹. Room temperature powder X-ray diffraction (XRD) of the material after cooling confirms presence of the lithium metasilicate and cristobalite as the main phases and shows, in addition, small amount of lithium disilicate and orthophosphate. ³¹P MAS-NMR reveals presence of the lithiorthophosphate (Li₃PO₄) before and after heat treatment. The melting of lithium disilicate on heating and crystallisation of lithium metasilicate on cooling agree with endothermic and exotermic features respectively observed by DSC. ²⁹Si MAS-NMR shows presence of lithium disilicate phase in the as-received glass-ceramic, though not in the major proportion, and lithium metasilicate in the material after heat treatment. Both phases have significantly long T₁ relaxation time, especially the lithium metasilicate, therefore, a quantitative analysis of the ²⁹Si MAS-NMR spectra was not attempted. Significance. The findings of the present work demonstrate importance of the commercially designed processing parameters in order to preserve desired characteristics of the material. Processing the Empress II at a rate slower than recommended 60°C min⁻¹ or long isothermal hold at the maximal processing temperature 920°C can cause crystallization of lithium metasilicate and cristobalite instead of lithium disilicate as major phase. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Molecular structure in the solid state by X-ray crystallography and SSNMR and in solution by NMR of two 1,4-diazepines

NASA Astrophysics Data System (ADS)

Nieto, Carla I.; Sanz, Dionisia; Claramunt, Rosa M.; Torralba, M. Carmen; Torres, M. Rosario; Alkorta, Ibon; Elguero, José

2018-03-01

The crystals of two 1,4-diazepines prepared from curcuminoid β-diketones and ethylenediamine were studied by X-ray crystallography and NMR. Their tautomerism, intramolecular hydrogen bonds and conformation were determined.

Dynamical effects in Bragg coherent x-ray diffraction imaging of finite crystals

NASA Astrophysics Data System (ADS)

Shabalin, A. G.; Yefanov, O. M.; Nosik, V. L.; Bushuev, V. A.; Vartanyants, I. A.

2017-08-01

We present simulations of Bragg coherent x-ray diffractive imaging (CXDI) data from finite crystals in the frame of the dynamical theory of x-ray diffraction. The developed approach is based on a numerical solution of modified Takagi-Taupin equations and can be applied for modeling of a broad range of x-ray diffraction experiments with finite three-dimensional crystals of arbitrary shape also in the presence of strain. We performed simulations for nanocrystals of a cubic and hemispherical shape of different sizes and provided a detailed analysis of artifacts in the Bragg CXDI reconstructions introduced by the dynamical diffraction. Based on our theoretical analysis we developed an analytical procedure to treat effects of refraction and absorption in the reconstruction. Our results elucidate limitations for the kinematical approach in the Bragg CXDI and suggest a natural criterion to distinguish between kinematical and dynamical cases in coherent x-ray diffraction on a finite crystal.

Application of Solid-State NMR to Reveal Structural Differences in Cefazolin Sodium Pentahydrate from Different Manufacturing Processes

NASA Astrophysics Data System (ADS)

Tian, Ye; Wang, Wei D.; Zou, Wen-Bo; Qian, Jian-Qin; Hu, Chang-Qin

2018-04-01

The solid form of an active pharmaceutical ingredient is important when developing a new chemical entity. A solid understanding of the crystal structure and morphology that affect the mechanical and physical characteristics of pharmaceutical powders determines the manufacturing process. Solid-state NMR, thermogravimetric analysis, X-ray diffraction, and Fourier-transform infrared spectroscopy were combined with theoretical calculation to investigate different crystal packings of α-cefazolin sodium from three different vendors and conformational polymorphism was identified to exist in the α-cefazolin sodium. Marginal differences observed among CEZ-Na pentahydrate 1, 2, and 3 were speculated as the proportion of conformation 2. Understanding the differences in the polymorphic structure of α-cefazolin sodium may help with making modifications to incorporate new knowledge with a product’s development.

Synthesis, characterization and biological activity of Rhein-cyclodextrin conjugate

NASA Astrophysics Data System (ADS)

Liu, Manshuo; Lv, Pin; Liao, Rongqiang; Zhao, Yulin; Yang, Bo

2017-01-01

Cyclodextrin conjugate complexation is a useful method to enhance the solubility and absorption of poorly soluble drugs. A series of new Rhein-β-cyclodextrin conjugates (Rh-CD conjugates) have been synthesized and examined. Rhein is covalently linked with the β-CD by amido linkage in a 1:1 molar ratio. The conjugates were characterized by 1H NMR, 13C NMR, HRMS, powder X-ray diffraction (powder XRD) as well as thermogravimetric analysis (TGA). The results reveal that incorporation of β-CD could improve the aqueous solubility of Rhein and the cytotoxicity against hepatocellular carcinoma (HepG2) cell line as well as antibacterial activity against three organisms. The improved biological activity and the satisfactory water solubility of the conjugates will be potentially useful for developing novel drug-cyclodextrin conjugates, such as herbal medicine.

Solid-state NMR study of geopolymer prepared by sol-gel chemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsai, Yi-Ling; Hanna, John V.; Lee, Yuan-Ling, E-mail: yuanlinglee@ntu.edu.t

2010-12-15

Geopolymers are a new class of materials formed by the condensation of aluminosilicates and silicates obtained from natural minerals or industrial wastes. In this work, the sol-gel method is used to synthesize precursor materials for the preparation of geopolymers. The geopolymer samples prepared by our synthetic route have been characterized by a series of physical techniques, including Fourier-transform infrared, X-ray diffraction, and multinuclear solid-state NMR. The results are very similar to those obtained for the geopolymers prepared from natural kaolinite. We believe that our synthetic approach can offer a good opportunity for the medical applications of geopolymer. -- Graphical abstract:more » Geopolymer prepared by the sol-gel route has the same spectroscopic properties as the sample prepared from the natural kaolinite. Display Omitted« less

Synthesis, spectroscopic, and molecular structure characterizations of some azo derivatives of 2-hydroxyacetophenone

NASA Astrophysics Data System (ADS)

Albayrak, Çiğdem; Gümrükçüoğlu, İsmail E.; Odabaşoğlu, Mustafa; İskeleli, Nazan Ocak; Ağar, Erbil

2009-08-01

Some novel azo compounds were prepared by the reaction of 2-hydroxyacetophenone with aniline and its substituted derivatives. The structures of synthesized azo compounds were determined by IR, UV-Vis, 1H NMR and 13C NMR spectroscopic techniques and the structures of some of these compounds were also determined by X-ray diffraction studies. Structural analysis using IR in solid state shows that the azo form is favoured in the azo compounds whereas UV-Vis analysis of the azo compounds in solution has shown that there is a azo and ionic form. The azo compounds in the basic solvents dimethylformamide (DMF) and dimethylsulfoxide (DMSO) are both azo and ionic form while these compounds in ethyl alcohol (EtOH) and chloroform (CHCl 3) are only azo form.

Crystal structure and theoretical calculations of Julocrotine, a natural product with antileishmanial activity

NASA Astrophysics Data System (ADS)

Moreira, Rafael Y. O.; Brasil, Davi S. B.; Alves, Cláudio N.; Guilhon, Giselle M. S. P.; Santos, Lourivaldo S.; Arruda, Mara S. P.; Müller, Adolfo H.; Barbosa, Patrícia S.; Abreu, Alcicley S.; Silva, Edilene O.; Rumjanek, Victor M.; Souza, Jaime, Jr.; da Silva, Albérico B. F.; Santos, Regina H. De A.

Julocrotine, N-(2,6-dioxo-1-phenethyl-piperidin-3-yl)-2-methyl-butyramide, is a potent antiproliferative agent against the promastigote and amastigote forms of Leishmania amazonensis (L.). In this work, the crystal structure of Julocrotine was solved by X-ray diffraction, and its geometrical parameters were compared with theoretical calculations at the B3LYP and HF level of theory. IR and NMR spectra also have been obtained and compared with theoretical calculations. IR absorptions calculated with the B3LYP level of theory employed together with the 6-311G+(d,p) basis set, are close to those observed experimentally. Theoretical NMR calculations show little deviation from experimental results. The results show that the theory is in accordance with the experimental data.0

Hydration products in sulfoaluminate cements: Evaluation of amorphous phases by XRD/solid-state NMR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gastaldi, D., E-mail: dgastaldi@buzziunicem.it; Paul, G., E-mail: geo.paul@uniupo.it; Marchese, L.

The hydration of four sulfoaluminate cements have been studied: three sulfoaluminate systems, having different content of sulfate and silicate, and one blend Portland-CSA-calcium sulfate binder. Hydration was followed up to 90 days by means of a combination of X-ray diffraction and solid state MAS-NMR; Differential scanning calorimetry and Scanning electron microscopy were also performed in order to help the interpretation of experimental data. High amount of amorphous phases were found in all the four systems: in low-sulfate cements, amorphous part is mainly ascribed to monosulfate and aluminium hydroxide, while strätlingite is observed if belite is present in the cement; inmore » the blend system, C-S-H contributes to the amorphous phase beyond monosulfate.« less

Synthesis, crystal structure, and biological evaluation of a series of phloretin derivatives.

PubMed

Wang, Li; Li, Zheng-Wei; Zhang, Wei; Xu, Rui; Gao, Fei; Liu, Yang-Feng; Li, Ya-Jun

2014-10-13

A one-step synthesis of phloretin derivatives 2-11 from phloretin in good to excellent yields is reported. Their structures were characterized by 1H-NMR, 13C-NMR and MS, and the structures of 8 and 11 were determined by X-ray diffraction analysis. A mechanism for the formation of 9-11 is proposed. Compared with the anticancer drug docetaxel, phloretin, phloretin derivatives and phlorizin exhibited moderate cytotoxicity toward the MDA-MB-231, SPC-A1, A549, MCF-7 and EC109 cell lines. Among all of the tested compounds, 7 exhibited the strongest cytotoxicity toward the five cell lines and was more active than docetaxel in MDA-MB-231 cells. Our findings suggest that these derivatives hold great promise for further development as anticancer agents.

Atomic contributions from spin-orbit coupling to 29Si NMR chemical shifts in metallasilatrane complexes.

PubMed

Autschbach, Jochen; Sutter, Kiplangat; Truflandier, Lionel A; Brendler, Erica; Wagler, Jörg

2012-10-01

New members of a novel class of metallasilatrane complexes [X-Si-(μ-mt)(4)-M-Y], with M=Ni, Pd, Pt, X=F, Cl, Y=Cl, Br, I, and mt=2-mercapto-1-methylimidazolide, have been synthesized and characterized structurally by X-ray diffraction and by (29)Si solid-state NMR. Spin-orbit (SO) effects on the (29)Si chemical shifts induced by the metal, by the sulfur atoms in the ligand, and by heavy halide ligands Y=Cl, Br, I were investigated with the help of relativistic density functional calculations. Operators used in the calculations were constructed such that SO coupling can selectively be switched off for certain atoms. The unexpectedly large SO effects on the (29)Si shielding in the Ni complex with X=Y=Cl reported recently originate directly from the Ni atom, not from other moderately heavy atoms in the complex. With respect to Pd, SO effects are amplified for Ni owing to its smaller ligand-field splitting, despite the smaller nuclear charge. In the X=Cl, Y=Cl, Br, I series of complexes the Y ligand strongly modulates the (29)Si shift by amplifying or suppressing the metal SO effects. The pronounced delocalization of the partially covalent M←Y bond plays an important role in modulating the (29)Si shielding. We also demonstrate an influence from the X ligand on the (29)Si SO shielding contributions originating at Y. The NMR spectra for [X-Si-(μ-mt)(4)-M-Y] must be interpreted mainly based on electronic and relativistic effects, rather than structural differences between the complexes. The results highlight the sometimes unintuitive role of SO coupling in NMR spectra of complexes containing heavy atoms. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Instrument and method for X-ray diffraction, fluorescence, and crystal texture analysis without sample preparation

NASA Technical Reports Server (NTRS)

Gendreau, Keith (Inventor); Martins, Jose Vanderlei (Inventor); Arzoumanian, Zaven (Inventor)

2010-01-01

An X-ray diffraction and X-ray fluorescence instrument for analyzing samples having no sample preparation includes a X-ray source configured to output a collimated X-ray beam comprising a continuum spectrum of X-rays to a predetermined coordinate and a photon-counting X-ray imaging spectrometer disposed to receive X-rays output from an unprepared sample disposed at the predetermined coordinate upon exposure of the unprepared sample to the collimated X-ray beam. The X-ray source and the photon-counting X-ray imaging spectrometer are arranged in a reflection geometry relative to the predetermined coordinate.

The investigation of order–disorder transition process of ZSM-5 induced by spark plasma sintering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Liang; Wang, Lianjun, E-mail: wanglj@dhu.edu.cn; Jiang, Wan

2014-04-01

Based on the amorphization of zeolites, an order–disorder transition method was used to prepare silica glass via Spark Plasma Sintering (SPS). In order to get a better understanding about the mechanism of amorphization induced by SPS, the intermediate products in this process were prepared and characterized by different characterization techniques. X-ray diffraction and High-energy synchrotron X-ray scattering show a gradual transformation from ordered crystal to glass. Local structural changes in glass network including Si–O bond length, O–Si–O bond angle, size of rings, coordination were detected by Infrared spectroscopy and {sup 29}Si magic-angle spinning nuclear magnetic resonance (NMR) spectroscopy. Topologically ordered,more » amorphous material with a different intermediate-range structure can be obtained by precise control of intermediate process which can be expected to optimize and design material. - Graphical abstract: Low-density, ordered zeolites collapse to the rigid amorphous glass through spark plasma sintering. The intermediate-range structure formed in the process of order–disorder transition may give rise to specific property. - Highlights: • Order–disorder transition process of ZSM-5 induced by spark plasma sintering was investigated using several methods including XRD, High-energy synchrotron X-ray scattering, SAXS, IR, NMR, ect. • Order–disorder transition induced by SPS was compared with TIA and PIA. • Three stages has been divided during the whole process. • The collapse temperature range which may give rise to intermediate-range structure has been located.« less

Philip A. Parilla | NREL

Science.gov Websites

atomic layer deposition for applications. He also manages the majority of X-ray characterization equipment at NREL, specifically X-ray diffraction and X-ray fluorescence instrumentation. Additionally, he for EERE's Hydrogen Storage program. He is also an expert in X-ray diffraction and X-ray fluorescence

Simulations of X-ray diffraction of shock-compressed single-crystal tantalum with synchrotron undulator sources.

PubMed

Tang, M X; Zhang, Y Y; E, J C; Luo, S N

2018-05-01

Polychromatic synchrotron undulator X-ray sources are useful for ultrafast single-crystal diffraction under shock compression. Here, simulations of X-ray diffraction of shock-compressed single-crystal tantalum with realistic undulator sources are reported, based on large-scale molecular dynamics simulations. Purely elastic deformation, elastic-plastic two-wave structure, and severe plastic deformation under different impact velocities are explored, as well as an edge release case. Transmission-mode diffraction simulations consider crystallographic orientation, loading direction, incident beam direction, X-ray spectrum bandwidth and realistic detector size. Diffraction patterns and reciprocal space nodes are obtained from atomic configurations for different loading (elastic and plastic) and detection conditions, and interpretation of the diffraction patterns is discussed.

Simulations of X-ray diffraction of shock-compressed single-crystal tantalum with synchrotron undulator sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, M. X.; Zhang, Y. Y.; E, J. C.

Polychromatic synchrotron undulator X-ray sources are useful for ultrafast single-crystal diffraction under shock compression. Here, simulations of X-ray diffraction of shock-compressed single-crystal tantalum with realistic undulator sources are reported, based on large-scale molecular dynamics simulations. Purely elastic deformation, elastic–plastic two-wave structure, and severe plastic deformation under different impact velocities are explored, as well as an edge release case. Transmission-mode diffraction simulations consider crystallographic orientation, loading direction, incident beam direction, X-ray spectrum bandwidth and realistic detector size. Diffraction patterns and reciprocal space nodes are obtained from atomic configurations for different loading (elastic and plastic) and detection conditions, and interpretation of themore » diffraction patterns is discussed.« less

Coherent X-ray diffraction imaging of nanoengineered polymeric capsules

NASA Astrophysics Data System (ADS)

Erokhina, S.; Pastorino, L.; Di Lisa, D.; Kiiamov, A. G.; Faizullina, A. R.; Tayurskii, D. A.; Iannotta, S.; Erokhin, V.

2017-10-01

For the first time, nanoengineered polymeric capsules and their architecture have been studied with coherent X-ray diffraction imaging technique. The use of coherent X-ray diffraction imaging technique allowed us to analyze the samples immersed in a liquid. We report about the significant difference between polymeric capsule architectures under dry and liquid conditions.

A high-transparency, micro-patternable chip for X-ray diffraction analysis of microcrystals under native growth conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murray, Thomas D.; Johns Hopkins University School of Medicine, Baltimore, MD 21205; Lyubimov, Artem Y.

A highly X-ray-transparent, silicon nitride-based device has been designed and fabricated to harvest protein microcrystals for high-resolution X-ray diffraction data collection using microfocus beamlines and XFELs. Microcrystals present a significant impediment to the determination of macromolecular structures by X-ray diffraction methods. Although microfocus synchrotron beamlines and X-ray free-electron lasers (XFELs) can enable the collection of interpretable diffraction data from microcrystals, there is a need for efficient methods of harvesting small volumes (<2 µl) of microcrystals grown under common laboratory formats and delivering them to an X-ray beam source under native growth conditions. One approach that shows promise in overcoming themore » challenges intrinsic to microcrystal analysis is to pair so-called ‘fixed-target’ sample-delivery devices with microbeam-based X-ray diffraction methods. However, to record weak diffraction patterns it is necessary to fabricate devices from X-ray-transparent materials that minimize background scattering. Presented here is the design of a new micro-diffraction device consisting of three layers fabricated from silicon nitride, photoresist and polyimide film. The chip features low X-ray scattering and X-ray absorption properties, and uses a customizable blend of hydrophobic and hydrophilic surface patterns to help localize microcrystals to defined regions. Microcrystals in their native growth conditions can be loaded into the chips with a standard pipette, allowing data collection at room temperature. Diffraction data collected from hen egg-white lysozyme microcrystals (10–15 µm) loaded into the chips yielded a complete, high-resolution (<1.6 Å) data set sufficient to determine a high-quality structure by molecular replacement. The features of the chip allow the rapid and user-friendly analysis of microcrystals grown under virtually any laboratory format at microfocus synchrotron beamlines and XFELs.« less

Racemic crystallography of synthetic protein enantiomers used to determine the X-ray structure of plectasin by direct methods

PubMed Central

Mandal, Kalyaneswar; Pentelute, Brad L; Tereshko, Valentina; Thammavongsa, Vilasak; Schneewind, Olaf; Kossiakoff, Anthony A; Kent, Stephen B H

2009-01-01

We describe the use of racemic crystallography to determine the X-ray structure of the natural product plectasin, a potent antimicrobial protein recently isolated from fungus. The protein enantiomers l-plectasin and d-plectasin were prepared by total chemical synthesis; interestingly, l-plectasin showed the expected antimicrobial activity, while d-plectasin was devoid of such activity. The mirror image proteins were then used for racemic crystallization. Synchrotron X-ray diffraction data were collected to atomic resolution from a racemic plectasin crystal; the racemate crystallized in the achiral centrosymmetric space group with one l-plectasin molecule and one d-plectasin molecule forming the unit cell. Dimer-like intermolecular interactions between the protein enantiomers were observed, which may account for the observed extremely low solvent content (13%–15%) and more highly ordered nature of the racemic crystals. The structure of the plectasin molecule was well defined for all 40 amino acids and was generally similar to the previously determined NMR structure, suggesting minimal impact of the crystal packing on the plectasin conformation. PMID:19472324

Probing the evolution of palladium species in Pd@MOF catalysts during the Heck coupling reaction: An operando X-ray absorption spectroscopy study.

PubMed

Yuan, Ning; Pascanu, Vlad; Huang, Zhehao; Valiente, Alejandro; Heidenreich, Niclas; Leubner, Sebastian; Inge, A Ken; Gaar, Jakob; Stock, Norbert; Persson, Ingmar; Martin-Matute, Belen; Zou, Xiaodong

2018-06-11

The mechanism of the Heck C-C coupling reaction catalyzed by Pd@MOFs has been investigated using operando X-ray absorption spectroscopy (XAS) and powder X-ray diffraction (PXRD) combined with transmission electron microscopy (TEM) analysis and nuclear magnetic resonance ( 1 H NMR) kinetic studies. A custom-made reaction cell was used allowing operando PXRD and XAS data collection using high-energy synchrotron radiation. By analyzing the XAS data in combination with ex situ studies, the evolution of the palladium species is followed from the as-synthesized to its deactivated form. An adaptive reaction mechanism is pro-posed. Mononuclear Pd(II) complexes are found to be the dominant active species at the beginning of the reaction, which then gradually transform into Pd nanoclusters with 13-20 Pd atoms on average in later catalytic turnovers. Consumption of available reagent and substrate leads to coordination of Cl - ions to their surfaces, which causes the poisoning of the active sites. By understanding the deactivation process, it was possible to tune the reaction conditions and prolong the lifetime of the catalyst.

Anti-contamination device for cryogenic soft X-ray diffraction microscopy

DOE PAGES

Huang, Xiaojing; Miao, Huijie; Nelson, Johanna; ...

2011-05-01

Cryogenic microscopy allows one to view frozen hydrated biological and soft matter specimens with good structural preservation and a high degree of stability against radiation damage. We describe a liquid nitrogen-cooled anti-contamination device for cryogenic X-ray diffraction microscopy. The anti-contaminator greatly reduces the buildup of ice layers on the specimen due to condensation of residual water vapor in the experimental vacuum chamber. We show by coherent X-ray diffraction measurements that this leads to fivefold reduction of background scattering, which is important for far-field X-ray diffraction microscopy of biological specimens.

Synthesis, growth, structural, spectral, thermal, chemical etching, linear and nonlinear optical and mechanical studies of an organic single crystal 4-chloro 4-nitrostilbene (CONS): a potential NLO material.

PubMed

Dinakaran, Paul M; Kalainathan, S

2013-07-01

4-Chloro 4-nitrostilbene (CONS) a new organic nonlinear optical material has been synthesized. Employing slow evaporation method, good optical quality single crystals (dimensions up to 6×2×3 mm(3)) have been grown using ethyl methyl ketone (EMK) as a solvent. The grown crystals have been subjected to various characterizations such as single crystal X-ray diffraction, powder XRD, Fourier Transform Infrared spectroscopy (FTIR), proton NMR, solid UV absorption, SHG studies. Single crystal X-ray diffraction reveals that the crystal system belongs to monoclinic with noncentrosymmetric space group P21. The UV-Vis absorption spectrum has been recorded and found that the cut off wavelength is 380 nm. Functional groups and the structure of the title compound have been confirmed by FTIR and (1)H NMR spectroscopic analyses respectively. Molecular mass of the CONS confirmed by the high resolution mass spectral analysis .The thermal behavior of the grown crystal has been studied by TG/DTA analysis and it shows the melting point is at 188.66 °C. Dislocations and growth pattern present in the grown crystal revealed by the etching study. The mechanical strength of the CONS crystal has been studied by Vicker's hardness measurement. The SHG efficiency of the grown crystal has been determined by Kurtz and Perry powder test which revealed that the CONS crystal (327 mV) has 15 times greater efficiency than that of KDP (21.7 mV). Copyright © 2013 Elsevier B.V. All rights reserved.

Synthesis, spectroscopic and theoretical studies of ethyl (2E)-3-amino-2-({[(4-benzoyl-1,5-diphenyl-1H-pyrazol-3-yl)carbonyl]amino}carbonothioyl)but-2-enoate butanol solvate.

PubMed

Koca, İrfan; Sert, Yusuf; Gümüş, Mehmet; Kani, İbrahim; Çırak, Çağrı

2014-01-24

We have synthesized ethyl (2E)-3-amino-2-({[(4-benzoyl-1,5-diphenyl-1H-pyrazol-3-yl)carbonyl]amino}carbonothioyl)but-2-enoate (2) by the reaction of 4-benzoyl-1,5-diphenyl-1H-pyrazole-3-carbonyl chloride (1), ammonium thiocyanate and ethyl 3-aminobut-2-enoate and then characterized by elemental analyses, IR, Raman, (1)H NMR, (13)C NMR and X-ray diffraction methods. The experimental and theoretical vibrational spectra of 2 were investigated. The experimental FT-IR (4000-400 cm(-1)) and Laser-Raman spectra (4000-100 cm(-1)) of the molecule in the solid phase were recorded. Theoretical vibrational frequencies and geometric parameters (bond lengths, bond angles) were calculated using Ab Initio Hartree Fock (HF), Density Functional Theory (B3LYP) methods with 6-311++G(d,p) basis set by Gaussian 09W program. The computed values of frequencies are scaled using a suitable scale factor to yield good coherence with the observed values. The assignments of the vibrational frequencies were performed by potential energy distribution (PED) analysis by using VEDA 4 program. The theoretical optimized geometric parameters and vibrational frequencies were compared with the corresponding experimental X-ray diffraction data, and they were seen to be in a good agreement with each other. Also, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies were calculated. Copyright © 2013 Elsevier B.V. All rights reserved.

Observation of electromigration in a Cu thin line by in situ coherent x-ray diffraction microscopy

NASA Astrophysics Data System (ADS)

Takahashi, Yukio; Nishino, Yoshinori; Furukawa, Hayato; Kubo, Hideto; Yamauchi, Kazuto; Ishikawa, Tetsuya; Matsubara, Eiichiro

2009-06-01

Electromigration (EM) in a 1-μm-thick Cu thin line was investigated by in situ coherent x-ray diffraction microscopy (CXDM). Characteristic x-ray speckle patterns due to both EM-induced voids and thermal deformation in the thin line were observed in the coherent x-ray diffraction patterns. Both parts of the voids and the deformation were successfully visualized in the images reconstructed from the diffraction patterns. This result not only represents the first demonstration of the visualization of structural changes in metallic materials by in situ CXDM but is also an important step toward studying the structural dynamics of nanomaterials using x-ray free-electron lasers in the near future.

Note: application of a pixel-array area detector to simultaneous single crystal X-ray diffraction and X-ray absorption spectroscopy measurements.

PubMed

Sun, Cheng-Jun; Zhang, Bangmin; Brewe, Dale L; Chen, Jing-Sheng; Chow, G M; Venkatesan, T; Heald, Steve M

2014-04-01

X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) are two main x-ray techniques in synchrotron radiation facilities. In this Note, we present an experimental setup capable of performing simultaneous XRD and XAS measurements by the application of a pixel-array area detector. For XRD, the momentum transfer in specular diffraction was measured by scanning the X-ray energy with fixed incoming and outgoing x-ray angles. By selecting a small fixed region of the detector to collect the XRD signal, the rest of the area was available for collecting the x-ray fluorescence for XAS measurements. The simultaneous measurement of XRD and X-ray absorption near edge structure for Pr0.67Sr0.33MnO3 film was demonstrated as a proof of principle for future time-resolved pump-probe measurements. A static sample makes it easy to maintain an accurate overlap of the X-ray spot and laser pump beam.

Deformation and Failure of Protein Materials in Physiologically Extreme Conditions and Disease

DTIC Science & Technology

2009-03-01

resonance (NMR) spectroscopy and X- ray crystallography have advanced our ability to identify 3D protein structures57. Site-specific studies using NMR, a... ray crystallography, providing structural and temporal information about mechanisms of deformation and assembly (for example in intermediate...tens of thousands of 3D atomistic protein structures, identifying the structure of numerous proteins from varying species sources60. X- ray

X-Ray Diffraction Wafer Mapping Method for Rhombohedral Super-Hetero-Epitaxy

NASA Technical Reports Server (NTRS)

Park, Yoonjoon; Choi, Sang Hyouk; King, Glen C.; Elliott, James R.; Dimarcantonio, Albert L.

2010-01-01

A new X-ray diffraction (XRD) method is provided to acquire XY mapping of the distribution of single crystals, poly-crystals, and twin defects across an entire wafer of rhombohedral super-hetero-epitaxial semiconductor material. In one embodiment, the method is performed with a point or line X-ray source with an X-ray incidence angle approximating a normal angle close to 90 deg, and in which the beam mask is preferably replaced with a crossed slit. While the wafer moves in the X and Y direction, a narrowly defined X-ray source illuminates the sample and the diffracted X-ray beam is monitored by the detector at a predefined angle. Preferably, the untilted, asymmetric scans are of {440} peaks, for twin defect characterization.

Diffraction based method to reconstruct the spectrum of the Thomson scattering x-ray source

NASA Astrophysics Data System (ADS)

Chi, Zhijun; Yan, Lixin; Zhang, Zhen; Zhou, Zheng; Zheng, Lianmin; Wang, Dong; Tian, Qili; Wang, Wei; Nie, Zan; Zhang, Jie; Du, Yingchao; Hua, Jianfei; Shi, Jiaru; Pai, Chihao; Lu, Wei; Huang, Wenhui; Chen, Huaibi; Tang, Chuanxiang

2017-04-01

As Thomson scattering x-ray sources based on the collision of intense laser and relativistic electrons have drawn much attention in various scientific fields, there is an increasing demand for the effective methods to reconstruct the spectrum information of the ultra-short and high-intensity x-ray pulses. In this paper, a precise spectrum measurement method for the Thomson scattering x-ray sources was proposed with the diffraction of a Highly Oriented Pyrolytic Graphite (HOPG) crystal and was demonstrated at the Tsinghua Thomson scattering X-ray source. The x-ray pulse is diffracted by a 15 mm (L) ×15 mm (H)× 1 mm (D) HOPG crystal with 1° mosaic spread. By analyzing the diffraction pattern, both x-ray peak energies and energy spectral bandwidths at different polar angles can be reconstructed, which agree well with the theoretical value and simulation. The higher integral reflectivity of the HOPG crystal makes this method possible for single-shot measurement.

Diffraction based method to reconstruct the spectrum of the Thomson scattering x-ray source.

PubMed

Chi, Zhijun; Yan, Lixin; Zhang, Zhen; Zhou, Zheng; Zheng, Lianmin; Wang, Dong; Tian, Qili; Wang, Wei; Nie, Zan; Zhang, Jie; Du, Yingchao; Hua, Jianfei; Shi, Jiaru; Pai, Chihao; Lu, Wei; Huang, Wenhui; Chen, Huaibi; Tang, Chuanxiang

2017-04-01

As Thomson scattering x-ray sources based on the collision of intense laser and relativistic electrons have drawn much attention in various scientific fields, there is an increasing demand for the effective methods to reconstruct the spectrum information of the ultra-short and high-intensity x-ray pulses. In this paper, a precise spectrum measurement method for the Thomson scattering x-ray sources was proposed with the diffraction of a Highly Oriented Pyrolytic Graphite (HOPG) crystal and was demonstrated at the Tsinghua Thomson scattering X-ray source. The x-ray pulse is diffracted by a 15 mm (L) ×15 mm (H)× 1 mm (D) HOPG crystal with 1° mosaic spread. By analyzing the diffraction pattern, both x-ray peak energies and energy spectral bandwidths at different polar angles can be reconstructed, which agree well with the theoretical value and simulation. The higher integral reflectivity of the HOPG crystal makes this method possible for single-shot measurement.

Gas gun shock experiments with single-pulse x-ray phase contrast imaging and diffraction at the Advanced Photon Source

NASA Astrophysics Data System (ADS)

Luo, S. N.; Jensen, B. J.; Hooks, D. E.; Fezzaa, K.; Ramos, K. J.; Yeager, J. D.; Kwiatkowski, K.; Shimada, T.

2012-07-01

The highly transient nature of shock loading and pronounced microstructure effects on dynamic materials response call for in situ, temporally and spatially resolved, x-ray-based diagnostics. Third-generation synchrotron x-ray sources are advantageous for x-ray phase contrast imaging (PCI) and diffraction under dynamic loading, due to their high photon fluxes, high coherency, and high pulse repetition rates. The feasibility of bulk-scale gas gun shock experiments with dynamic x-ray PCI and diffraction measurements was investigated at the beamline 32ID-B of the Advanced Photon Source. The x-ray beam characteristics, experimental setup, x-ray diagnostics, and static and dynamic test results are described. We demonstrate ultrafast, multiframe, single-pulse PCI measurements with unprecedented temporal (<100 ps) and spatial (˜2 μm) resolutions for bulk-scale shock experiments, as well as single-pulse dynamic Laue diffraction. The results not only substantiate the potential of synchrotron-based experiments for addressing a variety of shock physics problems, but also allow us to identify the technical challenges related to image detection, x-ray source, and dynamic loading.

An ambient stable core-substituted perylene bisimide dianion: isolation and single crystal structure analysis† †Electronic supplementary information (ESI) available: Synthesis, spectroelectrochemistry, UV-vis, electrochemistry, X-ray diffraction, NMR and mass spectra. CCDC 1032959. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4sc03671a Click here for additional data file. Click here for additional data file.

PubMed Central

Seifert, Sabine; Schmidt, David

2015-01-01

Here we report the first example of an isolable, ambient stable perylene bisimide (PBI) dianion which was synthesized by catalytic reduction of a highly electron deficient PBI derivative. The remarkable stability of this unprecedented dianion in air for months facilitated its complete characterization by different methods, including single crystal X-ray analysis. Furthermore, solvent dependent cyclic and square wave voltammetry studies revealed that the formation of PBI dianions is preferred in more polar solvents, whereas the generation of PBI radical anions should be favoured in less polar solvents. PMID:28717450

A 1:1 pharmaceutical cocrystal of myricetin in combination with uncommon piracetam conformer: X-ray single crystal analysis and mechanochemical synthesis

NASA Astrophysics Data System (ADS)

Sowa, Michał; Ślepokura, Katarzyna; Matczak-Jon, Ewa

2014-01-01

Combination of two Active Pharmaceutical Ingredients, myricetin and piracetam, yields a 1:1 cocrystal characterized by X-ray single-crystal and powder diffraction, Raman spectroscopy, 1H NMR, thermal analysis (DSC and TG-DTA) methods. Constituents of the cocrystalline phase were also investigated in terms of Hirshfeld surfaces. Compounds in their neutral forms cocrystallize in the Pna21 space group of orthorhombic system. Notably, piracetam adopts an uncommon conformation, not encountered in its cocrystals previously described. In the crystal lattice, a three-dimensional hydrogen-bonded network is observed, including formation of a 2D molecular scaffolding motif. A scale-up procedure is readily available with use of solvent-drop grinding method, in which application of a variety of common solvents leads to formation of the cocrystal, as confirmed by XRPD and Raman spectroscopy.

X-ray and neutron diffraction studies of crystallinity in hydroxyapatite coatings.

PubMed

Girardin, E; Millet, P; Lodini, A

2000-02-01

To standardize industrial implant production and make comparisons between different experimental results, we have to be able to quantify the crystallinity of hydroxyapatite. Methods of measuring crystallinity ratio were developed for various HA samples before and after plasma spraying. The first series of methods uses X-ray diffraction. The advantage of these methods is that X-ray diffraction equipment is used widely in science and industry. In the second series, a neutron diffraction method is developed and the results recorded are similar to those obtained by the modified X-ray diffraction methods. The advantage of neutron diffraction is the ability to obtain measurements deep inside a component. It is a nondestructive method, owing to the very low absorption of neutrons in most materials. Copyright 2000 John Wiley & Sons, Inc.

X-ray Diffraction Gratings for Astrophysics

NASA Astrophysics Data System (ADS)

Paerels, Frits

2010-12-01

Over the past year, we have celebrated the tenth anniversary of the Chandra and XMM-Newton X-ray observatories. Both carry powerful, novel diffraction grating spectrometers, which have opened true X-ray spectroscopy for astrophysics. I will describe the design and operation of these instruments, as the background to some of the beautiful results they have produced. But these designs do not exhaust the versatility and essential simplicity of diffraction grating spectrometers, and I will discuss applications for the International X-ray Observatory IXO.

Amorphous boron gasket in diamond anvil cell research

NASA Astrophysics Data System (ADS)

Lin, Jung-Fu; Shu, Jinfu; Mao, Ho-kwang; Hemley, Russell J.; Shen, Guoyin

2003-11-01

Recent advances in high-pressure diamond anvil cell experiments include high-energy synchrotron x-ray techniques as well as new cell designs and gasketing procedures. The success of high-pressure experiments usually depends on a well-prepared sample, in which the gasket plays an important role. Various gasket materials such as diamond, beryllium, rhenium, and stainless steel have been used. Here we introduce amorphous boron as another gasket material in high-pressure diamond anvil cell experiments. We have applied the boron gasket for laser-heating x-ray diffraction, radial x-ray diffraction, nuclear resonant inelastic x-ray scattering, and inelastic x-ray scattering. The high shear strength of the amorphous boron maximizes the thickness of the sample chamber and increases the pressure homogeneity, improving the quality of high-pressure data. Use of amorphous boron avoids unwanted x-ray diffraction peaks and reduces the absorption of incident and x rays exiting the gasket material. The high quality of the diffraction patterns makes it possible to refine the cell parameters with powder x-ray diffraction data under high pressure and high temperature. The reactivity of boron prevents its use at high temperatures, however. When heated, boron may also react with the specimen to produce unwanted phases. The relatively porous boron starting material at ambient conditions also poses some challenges for sample preparation.

Comparative theoretical and experimental study on novel tri-quinoline system and its anticancer studies

NASA Astrophysics Data System (ADS)

Gayathri, Kasirajan; Radhika, Ramachandran; Shankar, Ramasamy; Malathi, Mahalingam; Savithiri, Krishnaswamy; Sparkes, Hazel A.; Howard, Judith A. K.; Mohan, Palathurai Subramaniam

2017-04-01

A novel compound 2-chloro-3,6-bis-(quinolin-8-yloxymethyl)-quinoline 3 bearing a tri-quinoline moiety has been synthesized from 2-chloro-3,6-dimethyl quinoline 1 and 8-hydroxy quinoline 2 using dry acetone and K2CO3 as a base. 3 has been characterized by using FT-IR, FT-Raman, UV-Vis, 1H NMR, 13C NMR spectra and single crystal X-ray diffraction methods. We have also made a combined experimental and theoretical study on the molecular structure, vibrational spectra, NMR, FT-IR, FT-Raman and UV-Vis spectra of 2-chloro-3,6-bis-(quinolin-8-yloxymethyl)-quinoline. The theoretical studies of the title compound have been evaluated by using density functional theory calculations using B3LYP/6-31+G(d,p) and M06-2X/6-31+G(d,p) level of theories. The calculated theoretical values were found to be in good agreement with the experimental findings. The single crystal structure 3 crystallized in the orthorhombic space group Pna21. The compound 3 exhibits higher cytotoxicity in human cervical cancer cell lines (HeLa) than human breast cancer cell lines (MCF7).

X-Ray Sum Frequency Diffraction for Direct Imaging of Ultrafast Electron Dynamics

NASA Astrophysics Data System (ADS)

Rouxel, Jérémy R.; Kowalewski, Markus; Bennett, Kochise; Mukamel, Shaul

2018-06-01

X-ray diffraction from molecules in the ground state produces an image of their charge density, and time-resolved x-ray diffraction can thus monitor the motion of the nuclei. However, the density change of excited valence electrons upon optical excitation can barely be monitored with regular diffraction techniques due to the overwhelming background contribution of the core electrons. We present a nonlinear x-ray technique made possible by novel free electron laser sources, which provides a spatial electron density image of valence electron excitations. The technique, sum frequency generation carried out with a visible pump and a broadband x-ray diffraction pulse, yields snapshots of the transition charge densities, which represent the electron density variations upon optical excitation. The technique is illustrated by ab initio simulations of transition charge density imaging for the optically induced electronic dynamics in a donor or acceptor substituted stilbene.

Synthesis, surface chemistry and pseudocapacitance mechanisms of VN nanocrystals derived by a simple two-step halide approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Daiwon; Jampani, Prashanth H.; Jayakody, J. R. P.

Chloroamide precursors generated via a simple two-step ammonolysis reaction of transition metal chloride in the liquid phase at room temperature were heat treated in ammonia at moderate temperature to yield nano-sized VN crystallites. Grain growth inhibited by lowering the synthesis temperature (≈400°C) yielded agglomerated powders of spherical crystallites of cubic phase of VN with particle sizes as small as 6nm in diameter. X-ray diffraction, FTIR, mass spectroscopy (MS), and nuclear magnetic resonance (NMR) spectroscopy assessed the ammonolysis and nitridation reaction of the VCl 4-NH 3 system. X-ray Rietveld refinement, the BET technique and high-resolution transmission microscopy (HRTEM), energy dispersive x-raymore » (EDX) and thermogravimetric analysis (TGA) helped assess the crystallographic and microstructural nature of the VN nanocrystals. The surface chemistry and redox reaction leading to the gravimetric pseudo-capacitance value of (≈855 F/g) measured for the VN nanocrystals was determined and validated using FTIR, XPS and cyclic voltammetry analyses.« less

Chevrel-phase solid solution Mo 6Se 8- xTe x. Study of its superconducting, magnetic and NMR properties

NASA Astrophysics Data System (ADS)

Hamard1a, C.; Auffret, V.; Peña, O.; Le Floch, M.; Nowak, B.; Wojakowski, A.

2000-09-01

The Chevrel-phase solid solution Mo 6Se 8-Mo 6Te 8 was studied by X-ray diffraction, AC and DC magnetic susceptibility and 77Se and 125Te NMR spectroscopy. From the smooth evolution of the lattice parameters and superconducting critical temperatures, a progressive substitution of selenium atoms by tellurium is shown, on the whole range of composition 0⩽ x⩽8, in the formulation Mo 6Se 8- xTe x: the unit-cell volume increases linearly because of the larger ionic size of tellurium, while Tc decreases rapidly (from 6.45 down to 0 K) because of the different formal oxidation states of the anions and a probable evolution of the Fermi level in the density of states. Results of magnetic susceptibility support this model and suggest the inhibition of the intrinsic metallic behavior with increasing x. The NMR spectra of the binaries Mo 6Se 8 and Mo 6Te 8 reveal two significant features, attributed to two different chalcogen positions in the R 3¯ symmetry. At low Se contents in Mo 6Se 8- xTe x ( x=7.5, 7 and 6), selenium first fills the two X(2) sites along the three-fold axis (2c positions), and then it becomes statistically distributed over the general 6f positions, leading to broad 77Se NMR lines. On the other hand, substitution of Te atoms in Mo 6Se 8 seems to occur in a random way, creating large perturbations on the 125Te NMR spectra, over the whole range of x. Theoretical analysis based on the presence of two anisotropic lines (of axial and non-axial symmetries, respectively) allowed us to estimate their anisotropy factors and to perfectly simulate the frequency response of both Mo 6Se 8 and Mo 6Te 8 binaries. Analysis of the Knight shift anisotropy leads us to conclude about the importance of the molybdenum z 2 molecular orbital contribution which controls the Mo-X dipolar interactions.

Crystal growth, structural, optical, spectral and thermal studies of tris(L-phenylalanine)L-phenylalaninium nitrate: a new organic nonlinear optical material.

PubMed

Prakash, M; Geetha, D; Lydia Caroline, M

2011-10-15

Tris(L-phenylalanine)L-phenylalaninium nitrate, C(9)H(12)NO(2)(+)·NO(3)(-)·3C(9)H(11)NO(2) (TPLPN), a new organic nonlinear optical material was grown from aqueous solution by slow evaporation solution growth at room temperature. The grown crystals were subjected to powder X-ray diffraction and single crystal X-ray diffraction studies to confirm the crystalline nature and crystal structure. The modes of vibration of different molecular groups present in TPLPN have been identified by FTIR spectral analysis. The presence of hydrogen and carbon in the grown crystal were confirmed by using proton and carbon nuclear magnetic resonance (NMR) spectral analyses. The optical transmission spectral study establishes good transmitting ability of the crystal in the entire visible region. The thermogravimetric (TG) and differential thermal analyses (DTA) were carried out to understand the thermal stability of the sample. The nonlinear optical property of the compound observed using Kurtz powder second harmonic generation test assets the suitability of the grown material for the frequency conversion of laser radiation of Nd:YAG. Copyright © 2011 Elsevier B.V. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, C.W.B.; Das Gupta, S.K.; Mattai, J.

Solid-state nuclear magnetic resonance (NMR) spectroscopy and X-ray powder diffraction were used to investigate the mechanism of trehalose (TRE) stabilization of lipid bilayers. Calorimetric investigation of dry TRE-stabilized bilayers reveals a first-order phase transition at temperatures similar to the transition of hydrated lipid bilayers. X-ray diffraction studies show that dry mixtures of TRE and 1,2-dipalmitoyl-sn-phosphatidylcholine (DPPC) have a lamellar structure with excess crystalline TRE being present. {sup 2}H spectra of the choline headgroup show hindered molecular motions as compared to dry DPPC alone, and {sup 13}C spectra of the sn-2-carbonyl show rigid lattice powder patterns indicting very little motion atmore » the headgroup and interfacial regions. Thus, the sugar interacts extensively with the hydrophilic regions of the lipid, from the choline and the phosphate moieties in the headgroup to the glycerol and carbonyls in the interfacial region. The authors postulate that the sugar and the lipid form an extensive hydrogen-bonded network with the sugar acting as a spacer to expand the distance between lipids in the bilayer. The fluididty of the hydrophobic region in the L{sub {lambda}} phase together with the bilayer stabilization at the headgroup contributes to membrane viability in anhydrobiotic organisms.« less

Crystal structure, molecular docking, and biological activity of the zinc complexes with 2-thenoyltrifluoroacetone and N-donor heterocyclic ligands

NASA Astrophysics Data System (ADS)

Eshaghi Malekshah, Rahime; Salehi, Mehdi; Kubicki, Maciej; Khaleghian, Ali

2017-12-01

Two novel mononuclear complexes, [Zn (TTA) (bipy)Cl] (1) and [Zn (TTA) (phen)Cl] (2) (TTA = 4,4,4-Trifluoro-1-(2-furyl)-1,3-butanedione, phen = 1,10-phenanthroline and bipy 2, 2ʹ-bipyridine), were synthesized and fully characterized by elemental analyses, 1H NMR, UV-Vis, FTIR spectroscopy, and conductivity measurements. The crystal structures of these two mono-nuclear zinc (II) complexes were determined by X-ray single-crystal diffraction. The result of X-ray diffraction analyses revealed that both complexes have distorted tetragonal-pyramid structures. In MTT cytotoxicity studies, these Zn (II) complexes exhibited antitumor activity against MCF-7 and MKN-45 cell lines. It was also found that the proliferation rate of MCF-7 and MKN-45 cells decreased after treatment with the above-mentioned complexes. In addition, the apoptosis-inducing activity was assessed by AO/EB (Acridine Orange/Ethidium bromide) staining assay and found that they have the potential to act as effective metal-based anticancer drugs. Finally, the molecular docking studies showed that complex 2 strongly binds through minor groove with DNA by relative binding energy -7.33 kcal mol-1.

Vibrational cross-angles in condensed molecules: a structural tool.

PubMed

Chen, Hailong; Zhang, Yufan; Li, Jiebo; Liu, Hongjun; Jiang, De-En; Zheng, Junrong

2013-09-05

The fluctuations of three-dimensional molecular conformations of a molecule in different environments play critical roles in many important chemical and biological processes. X-ray diffraction (XRD) techniques and nuclear magnetic resonance (NMR) methods are routinely applied to monitor the molecular conformations in condensed phases. However, some special requirements of the methods have prevented them from exploring many molecular phenomena at the current stage. Here, we introduce another method to resolve molecular conformations based on an ultrafast MIR/T-Hz multiple-dimensional vibrational spectroscopic technique. The model molecule (4'-methyl-2'-nitroacetanilide, MNA) is prepared in two of its crystalline forms and liquid samples. Two polarized ultrafast infrared pulses are then used to determine the cross-angles of vibrational transition moment directions by exciting one vibrational band and detecting the induced response on another vibrational band of the molecule. The vibrational cross-angles are then converted into molecular conformations with the aid of calculations. The molecular conformations determined by the method are supported by X-ray diffraction and molecular dynamics simulation results. The experimental results suggest that thermodynamic interactions with solvent molecules are not altering the molecular conformations of MNA in the solutions to control their ultimate conformations in the crystals.

Synthesis, crystal structures and spectroscopic properties of triazine-based hydrazone derivatives; a comparative experimental-theoretical study.

PubMed

Arshad, Muhammad Nadeem; Bibi, Aisha; Mahmood, Tariq; Asiri, Abdullah M; Ayub, Khurshid

2015-04-03

We report here a comparative theoretical and experimental study of four triazine-based hydrazone derivatives. The hydrazones are synthesized by a three step process from commercially available benzil and thiosemicarbazide. The structures of all compounds were determined by using the UV-Vis., FT-IR, NMR (1H and 13C) spectroscopic techniques and finally confirmed unequivocally by single crystal X-ray diffraction analysis. Experimental geometric parameters and spectroscopic properties of the triazine based hydrazones are compared with those obtained from density functional theory (DFT) studies. The model developed here comprises of geometry optimization at B3LYP/6-31G (d, p) level of DFT. Optimized geometric parameters of all four compounds showed excellent correlations with the results obtained from X-ray diffraction studies. The vibrational spectra show nice correlations with the experimental IR spectra. Moreover, the simulated absorption spectra also agree well with experimental results (within 10-20 nm). The molecular electrostatic potential (MEP) mapped over the entire stabilized geometries of the compounds indicated their chemical reactivates. Furthermore, frontier molecular orbital (electronic properties) and first hyperpolarizability (nonlinear optical response) were also computed at the B3LYP/6-31G (d, p) level of theory.

Structure and vibrational spectra of melaminium bis(trifluoroacetate) trihydrate: FT-IR, FT-Raman and quantum chemical calculations.

PubMed

Sangeetha, V; Govindarajan, M; Kanagathara, N; Marchewka, M K; Gunasekaran, S; Anbalagan, G

2014-05-05

Melaminium bis(trifluoroacetate) trihydrate (MTFA), an organic material has been synthesized and single crystals of MTFA have been grown by the slow solvent evaporation method at room temperature. X-ray powder diffraction analysis confirms that MTFA crystal belongs to the monoclinic system with space group P2/c. The molecular geometry, vibrational frequencies and intensity of the vibrational bands have been interpreted with the aid of structure optimization based on density functional theory (DFT) B3LYP method with 6-311G(d,p) and 6-311++G(d,p) basis sets. The X-ray diffraction data have been compared with the data of optimized molecular structure. The theoretical results show that the crystal structure can be reproduced by optimized geometry and the vibrational frequencies show good agreement with the experimental values. The nuclear magnetic resonance (NMR) chemical shift of the molecule has been calculated by the gauge independent atomic orbital (GIAO) method and compared with experimental results. HOMO-LUMO, and other related molecular and electronic properties are calculated. The Mulliken and NBO charges have also been calculated and interpreted. Copyright © 2014 Elsevier B.V. All rights reserved.

Simultaneous use of solution NMR and X-ray data in REFMAC5 for joint refinement/detection of structural differences.

PubMed

Rinaldelli, Mauro; Ravera, Enrico; Calderone, Vito; Parigi, Giacomo; Murshudov, Garib N; Luchinat, Claudio

2014-04-01

The program REFMAC5 from CCP4 was modified to allow the simultaneous use of X-ray crystallographic data and paramagnetic NMR data (pseudocontact shifts and self-orientation residual dipolar couplings) and/or diamagnetic residual dipolar couplings. Incorporation of these long-range NMR restraints in REFMAC5 can reveal differences between solid-state and solution conformations of molecules or, in their absence, can be used together with X-ray crystallographic data for structural refinement. Since NMR and X-ray data are complementary, when a single structure is consistent with both sets of data and still maintains reasonably `ideal' geometries, the reliability of the derived atomic model is expected to increase. The program was tested on five different proteins: the catalytic domain of matrix metalloproteinase 1, GB3, ubiquitin, free calmodulin and calmodulin complexed with a peptide. In some cases the joint refinement produced a single model consistent with both sets of observations, while in other cases it indicated, outside the experimental uncertainty, the presence of different protein conformations in solution and in the solid state.

Behavior of atypical amphiphilic molecules

NASA Astrophysics Data System (ADS)

Ko, John

1997-08-01

The physical behavior of several atypical amphiphilic molecules was studied in various environments including micelles, model bilayer membranes, and emulsions. The molecules under investigation were nor-chenodeoxycholic acid (nor-CDCA), ursodeoxycholic acid (UDCA), sphingosine (Sp), sphingosine hydrochloride (SpċHCl), and tetrahydrolipstatin (THL). The bile acids, nor-CDCA and UDCA, were studied using 13C-Nuclear Magnetic Resonance ([13C) -NMR) in micelles of taurocholate and in bilayers of phosphatidylcholine. The pK a values of the bile acids in each environment were determined by [13C) -NMR and are as follows: 6.08 ±.03 for nor-CDCA and 6.27 ±.01 for UDCA in micelles, and 7.04 ± 12 for nor-CDCA and 6.89 ±.05 for UDCA in vesicles. Using line shape analysis, the transbilayer movement rate at 36oC for nor-CDCA and UDCA was calculated to be 580 sec--1 and 409 sec-1, respectively. [13C) -NMR titration of Sp gave pK a values of 9.09 ±.02 in micelles and 9.69 ±.21 in bilayers. Differential scanning calorimetry (DSC) and X-ray diffraction were used to establish the Spċwater and SpċHClċwater phase diagrams. Anhydrous and hydrated samples ranging from 5- 90% water were analyzed. The DSC thermograms traced out the transition temperatures of each molecule while the X- ray diffraction patterns revealed their chain and crystalline lattice packing structures. In general, sphingosine exists as a hydrated crystal with β packing phase below 43oC and melts into an Lα phase. Sphingosine hydrochloride, however, exists as a gel phase (L_beta or /beta/sp') below 42oC that swells to 61% hydration. At low water concentrations (0-64%), a lamellar liquid crystal phase (L_alpha) is formed above the chain melting transition of 42oC. At medium concentration (65%), a Hexagonal I phase is present, and at high water concentrations (66-90%), a micellar phase is present. THL, a specific inhibitor of lipases, was analyzed with [ 13C) -NMR to study its behavior in various environments, ranging from carbon tetrachloride to water to pure triolein. THL was also incorporated into phosphatidylcholine bilayers and into microemulsions of triolein and phosphatidylcholine. [ 13C) -NMR analysis revealed that THL gets incorporated into the surface of vesicles, and into both the surface and core of microemulsion particles.

Arrays of Molecular Rotors with Triptycene Stoppers: Surface Inclusion in Hexagonal Tris(o-phenylenedioxy)cyclotriphosphazene.

PubMed

Kaleta, Jiří; Dron, Paul I; Zhao, Ke; Shen, Yongqiang; Císařová, Ivana; Rogers, Charles T; Michl, Josef

2015-06-19

A new generation of rod-shaped dipolar molecular rotors designed for controlled insertion into channel arrays in the surface of hexagonal tris(o-phenylenedioxy)cyclotriphosphazene (TPP) has been designed and synthesized. Triptycene is used as a stopper intended to prevent complete insertion, forcing the formation of a surface inclusion. Two widely separated (13)C NMR markers are present in the shaft for monitoring the degree of insertion. The structure of the two-dimensional rotor arrays contained in these surface inclusions was examined by solid-state NMR and X-ray powder diffraction. The NMR markers and the triptycene stopper functioned as designed, but half of the guest molecules were not inserted as deeply into the TPP channels as the other half. As a result, the dipolar rotators were distributed equally in two planes parallel to the crystal surface instead of being located in a single plane as would be required for ferroelectricity. Dielectric spectroscopy revealed rotational barriers of ∼4 kcal/mol but no ferroelectric behavior.

An unexpected reaction pathway in the synthesis of the ABCE framework of strychnine-type alkaloids - A multidisciplinary study

NASA Astrophysics Data System (ADS)

Šoral, Michal; Markus, Jozef; Doháňošová, Jana; Šoralová, Stanislava; Dvoranová, Dana; Chyba, Andrej; Moncol, Ján; Berkeš, Dušan; Liptaj, Tibor

2017-01-01

Acid-catalyzed cyclization of spirocyclic 1‧-benzyl-2‧-(prop-2-en-1-yl)spiro[indole-3,3‧-pyrrolidine]-5‧-one (1) was performed. The pentacyclic product of Povarov-like imino-Diels-Alder reaction was isolated in high yield instead of expected tetracyclic aza-Prins intermediate. The unusual exotic alkaloid-type structure of the resulting molecule 2 was unambiguously confirmed by a detailed NMR analysis using a set of 2D NMR spectra including an INADEQUATE experiment. The relative configuration of 2 was predicted from the synthesis mechanism and DFT geometry calculations and independently confirmed using NOESY and residual dipolar coupling (RDC) assisted NMR analysis in stretched crosslinked polystyrene gels. The reversibility of the cycloaddition in aprotic solvents was observed. A new reaction pathway yielding a rare 6-5-5-5 tetracyclic spiroindoline 3 was suggested. The relative configuration within the tetracyclic framework was ultimately proved using Single-crystal X-ray diffraction analysis of compound 4.

Spectroscopic and structural studies of the first complex formed between salinomycin and organic amine

NASA Astrophysics Data System (ADS)

Antoszczak, Michał; Janczak, Jan; Brzezinski, Bogumił; Huczyński, Adam

2017-02-01

For the first time, the crystalline complex of salinomycin with benzylamine was obtained and its molecular structure was studied using single crystal X-ray diffraction, FT-IR, 1H NMR, 13C NMR, 2D NMR and ESI MS methods. These studies provided evidence that the proton from the carboxylic group of salinomycin (SAL) is transferred to the amine group of benzylamine (BnA) forming the host-guest complex (SAL-BnA). It was shown that the SAL-BnA complex both in solid state and in chloroform solution is stabilized by the intramolecular O-H⋯O hydrogen bonds and also by the intermolecular hydrogen bonding interactions of the carboxylate, ketone and/or hydroxyl groups of SAL with water molecules present in the investigated system. The solvated acetonitrile molecules are additionally located in the voids between the SAL-BnA complex molecules in the crystal structure, while water molecules involved in the dihydrated crystalline SAL-BnA complex partially move into the solvent upon dissolution in chloroform.

An NMR crystallography study of the hemihydrate of 2', 3'-O-isopropylidineguanosine.

PubMed

Reddy, G N Manjunatha; Cook, Daniel S; Iuga, Dinu; Walton, Richard I; Marsh, Andrew; Brown, Steven P

2015-02-01

An NMR crystallography study of the hemihydrate of 2', 3'-O-isopropylidineguanosine (Gace) is presented, together with powder X-ray diffraction and thermogravimetric analysis. (1)H double-quantum and (14)N-(1)H HMQC spectra recorded at 850MHz and 75kHz MAS (using a JEOL 1mm probe) are presented together with a (1)H-(13)C refocused INEPT spectrum recorded at 500MHz and 12.5kHz MAS using eDUMBO-122(1)H homonuclear decoupling. NMR chemical shieldings are calculated using the GIPAW (gauge-including projector augmented wave) method; good two-dimensional agreement between calculation and experiment is observed for (13)C and (1)H chemical shifts for directly bonded CH and CH3 peaks. There are two Gace molecules in the asymmetric unit cell: differences in specific (1)H chemical shifts are rationalised in terms of the strength of CH-π and intermolecular hydrogen bonding interactions. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

CFA-1: the first chiral metal-organic framework containing Kuratowski-type secondary building units.

PubMed

Schmieder, Phillip; Denysenko, Dmytro; Grzywa, Maciej; Baumgärtner, Benjamin; Senkovska, Irena; Kaskel, Stefan; Sastre, German; van Wüllen, Leo; Volkmer, Dirk

2013-08-14

The novel homochiral metal-organic framework CFA-1 (Coordination Framework Augsburg-1), [Zn5(OAc)4(bibta)3], containing the achiral linker {H2-bibta = 1H,1'H-5,5'-bibenzo[d][1,2,3]triazole}, has been synthesised. The reaction of H2-bibta and Zn(OAc)2·2H2O in N-methylformamide (NMF) (90 °C, 3 d) yields CFA-1 as trigonal prismatic single crystals. CFA-1 serves as a convenient precursor for the synthesis of isostructural frameworks with redox-active metal centres, which is demonstrated by the postsynthetic exchange of Zn(2+) by Co(2+) ions. The framework is robust to solvent removal and has been structurally characterized by synchrotron single-crystal X-ray diffraction and solid state NMR measurements ((13)C MAS- and (1)H MAS-NMR at 10 kHz). Results from MAS-NMR and IR spectroscopy studies are corroborated by cluster and periodic DFT calculations performed on CFA-1 cluster fragments.

Development of an adaptable coherent x-ray diffraction microscope with the emphasis on imaging hydrated specimens.

PubMed

Nam, Daewoong; Park, Jaehyun; Gallagher-Jones, Marcus; Shimada, Hiroki; Kim, Sangsoo; Kim, Sunam; Kohmura, Yoshiki; Ishikawa, Tetsuya; Song, Changyong

2013-11-01

This paper describes the development of a versatile coherent x-ray diffraction microscope capable of imaging biological specimens in solution. The microscope is a flexible platform accommodating various conditions, from low vacuum (10(-2) Pa) to helium gas filled ambient pressure. This flexibility greatly expands the application area, from in situ materials science to biology systems in their native state, by significantly relaxing restrictions to the sample environment. The coherent diffraction microscope has been used successfully to image a yeast cell immersed in buffer solution. We believe that the design of this coherent diffraction microscope can be directly adapted to various platforms such as table top soft x-ray laser, synchrotron x-ray sources, and x-ray free electron laser with minor relevant adjustments.

Development of an adaptable coherent x-ray diffraction microscope with the emphasis on imaging hydrated specimens

NASA Astrophysics Data System (ADS)

Nam, Daewoong; Park, Jaehyun; Gallagher-Jones, Marcus; Shimada, Hiroki; Kim, Sangsoo; Kim, Sunam; Kohmura, Yoshiki; Ishikawa, Tetsuya; Song, Changyong

2013-11-01

This paper describes the development of a versatile coherent x-ray diffraction microscope capable of imaging biological specimens in solution. The microscope is a flexible platform accommodating various conditions, from low vacuum (10-2 Pa) to helium gas filled ambient pressure. This flexibility greatly expands the application area, from in situ materials science to biology systems in their native state, by significantly relaxing restrictions to the sample environment. The coherent diffraction microscope has been used successfully to image a yeast cell immersed in buffer solution. We believe that the design of this coherent diffraction microscope can be directly adapted to various platforms such as table top soft x-ray laser, synchrotron x-ray sources, and x-ray free electron laser with minor relevant adjustments.

Thin Film Research. Volume 1

DTIC Science & Technology

1985-05-30

Order (FECO) ......... 23 3. X -Ray Diffraction ............................... 26 4. Transmission Electron Microscopy (TEM) ............... 26 5...remained amorphous after bombardment, as evidenced by X - ray diffraction, and showed no other changes. 0 (2) For Sb203, the crystallite size was reduced...main effect on MgF2 was the reduction in crystallite size. The films were too thir. for meaningful x - ray diffraction analysis. Durability and

X-Ray Diffraction and the Discovery of the Structure of DNA

ERIC Educational Resources Information Center

Crouse, David T.

2007-01-01

A method is described for teaching the analysis of X-ray diffraction of DNA through a series of steps utilizing the original methods used by James Watson, Francis Crick, Maurice Wilkins and Rosalind Franklin. The X-ray diffraction pattern led to the conclusion of the basic helical structure of DNA and its dimensions while basic chemical principles…

High Resolution X-Ray Diffraction of Macromolecules with Synchrotron Radiation

NASA Technical Reports Server (NTRS)

Stojanoff, Vivian; Boggon, Titus; Helliwell, John R.; Judge, Russell; Olczak, Alex; Snell, Edward H.; Siddons, D. Peter; Rose, M. Franklin (Technical Monitor)

2000-01-01

We recently combined synchrotron-based monochromatic X-ray diffraction topography methods with triple axis diffractometry and rocking curve measurements: high resolution X-ray diffraction imaging techniques, to better understand the quality of protein crystals. We discuss these methods in the light of results obtained on crystals grown under different conditions. These non destructive techniques are powerful tools in the characterization of the protein crystals and ultimately will allow to improve, develop, and understand protein crystal growth. High resolution X-ray diffraction imaging methods will be discussed in detail in light of recent results obtained on Hen Egg White Lysozyme crystals and other proteins.

Hard X-ray polarizer to enable simultaneous three-dimensional nanoscale imaging of magnetic structure and lattice strain

DOE PAGES

Logan, Jonathan; Harder, Ross; Li, Luxi; ...

2016-01-01

Recent progress in the development of dichroic Bragg coherent diffractive imaging, a new technique for simultaneous three-dimensional imaging of strain and magnetization at the nanoscale, is reported. This progress includes the installation of a diamond X-ray phase retarder at beamline 34-ID-C of the Advanced Photon Source. Here, the performance of the phase retarder for tuning X-ray polarization is demonstrated with temperature-dependent X-ray magnetic circular dichroism measurements on a gadolinium foil in transmission and on a Gd 5Si 2Ge 2crystal in diffraction geometry with a partially coherent, focused X-ray beam. Feasibility tests for dichroic Bragg coherent diffractive imaging are presented. Thesemore » tests include (1) using conventional Bragg coherent diffractive imaging to determine whether the phase retarder introduces aberrations using a nonmagnetic gold nanocrystal as a control sample, and (2) collecting coherent diffraction patterns of a magnetic Gd 5Si 2Ge 2nanocrystal with left- and right-circularly polarized X-rays. Future applications of dichroic Bragg coherent diffractive imaging for the correlation of strain and lattice defects with magnetic ordering and inhomogeneities are considered.« less

{sup 45}Sc Solid State NMR studies of the silicides ScTSi (T=Co, Ni, Cu, Ru, Rh, Pd, Ir, Pt)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harmening, Thomas; Eckert, Hellmut, E-mail: eckerth@uni-muenster.de; Fehse, Constanze M.

The silicides ScTSi (T=Fe, Co, Ni, Cu, Ru, Rh, Pd, Ir, Pt) were synthesized by arc-melting and characterized by X-ray powder diffraction. The structures of ScCoSi, ScRuSi, ScPdSi, and ScIrSi were refined from single crystal diffractometer data. These silicides crystallize with the TiNiSi type, space group Pnma. No systematic influences of the {sup 45}Sc isotropic magnetic shift and nuclear electric quadrupolar coupling parameters on various structural distortion parameters calculated from the crystal structure data can be detected. {sup 45}Sc MAS-NMR data suggest systematic trends in the local electronic structure probed by the scandium atoms: both the electric field gradients andmore » the isotropic magnetic shifts relative to a 0.2 M aqueous Sc(NO{sub 3}){sub 3} solution decrease with increasing valence electron concentration and within each T group the isotropic magnetic shift decreases monotonically with increasing atomic number. The {sup 45}Sc nuclear electric quadrupolar coupling constants are generally well reproduced by quantum mechanical electric field gradient calculations using the WIEN2k code. Highlights: Black-Right-Pointing-Pointer Arc-melting synthesis of silicides ScTSi. Black-Right-Pointing-Pointer Single crystal X-ray data of ScCoSi, ScRuSi, ScPdSi, and ScIrSi. Black-Right-Pointing-Pointer {sup 45}Sc solid state NMR of silicides ScTSi.« less

Coordination geometry of lead carboxylates - spectroscopic and crystallographic evidence.

PubMed

Catalano, Jaclyn; Murphy, Anna; Yao, Yao; Yap, Glenn P A; Zumbulyadis, Nicholas; Centeno, Silvia A; Dybowski, Cecil

2015-02-07

Despite their versatility, only a few single-crystal X-ray structures of lead carboxylates exist, due to difficulties with solubility. In particular, the structures of long-chain metal carboxylates have not been reported. The lone electron pair in Pb(ii) can be stereochemically active or inactive, leading to two types of coordination geometries commonly referred to as hemidirected and holodirected structures, respectively. We report (13)C and (207)Pb solid-state NMR and infrared spectra for a series of lead carboxylates, ranging from lead hexanoate (C6) to lead hexadecanoate (C18). The lead carboxylates based on consistent NMR parameters can be divided in two groups, shorter-chain (C6, C7, and C8) and longer-chain (C9, C10, C11, C12, C14, C16, and C18) carboxylates. This dichotomy suggests two modes of packing in these solids, one for the short-chain lead carboxylates and one for long-chain lead carboxylates. The consistency of the (13)C and (207)Pb NMR parameters, as well as the IR data, in each group suggests that each motif represents a structure characteristic of each subgroup. We also report the single-crystal X-ray diffraction structure of lead nonanoate (C9), the first single-crystal structure to have been reported for the longer-chain subgroup. Taken together the evidence suggests that the coordination geometry of C6-C8 lead carboxylates is hemidirected, and that of C9-C14, C16 and C18 lead carboxylates is holodirected.

Three Dimensional Variable-Wavelength X-Ray Bragg Coherent Diffraction Imaging

DOE PAGES

Cha, W.; Ulvestad, A.; Allain, M.; ...

2016-11-23

Here, we present and demonstrate a formalism by which three-dimensional (3D) Bragg x-ray coherent diffraction imaging (BCDI) can be implemented without moving the sample by scanning the energy of the incident x-ray beam. This capability is made possible by introducing a 3D Fourier transform that accounts for x-ray wavelength variability. We also demonstrate the approach by inverting coherent Bragg diffraction patterns from a gold nanocrystal measured with an x-ray energy scan. Furthermore, variable-wavelength BCDI will expand the breadth of feasible in situ 3D strain imaging experiments towards more diverse materials environments, especially where sample manipulation is difficult.

Synchrotron X-Ray Diffraction Analysis of Meteorites in Thin Section: Preliminary Results

NASA Technical Reports Server (NTRS)

Treiman, A. H.; Lanzirotti, A.; Xirouchakis, D.

2004-01-01

X-ray diffraction is the pre-eminent technique for mineral identification and structure determination, but is difficult to apply to grains in thin section, the standard meteorite preparation. Bright focused X-ray beams from synchrotrons have been used extensively in mineralogy and have been applied to extraterrestrial particles. The intensity and small spot size achievable in synchrotron X-ray beams makes them useful for study of materials in thin sections. Here, we describe Synchrotron X-ray Diffraction (SXRD) in thin section as done at the National Synchrotron Light Source, and cite examples of its value for studies of meteorites in thin section.

Three Dimensional Variable-Wavelength X-Ray Bragg Coherent Diffraction Imaging

NASA Astrophysics Data System (ADS)

Cha, W.; Ulvestad, A.; Allain, M.; Chamard, V.; Harder, R.; Leake, S. J.; Maser, J.; Fuoss, P. H.; Hruszkewycz, S. O.

2016-11-01

We present and demonstrate a formalism by which three-dimensional (3D) Bragg x-ray coherent diffraction imaging (BCDI) can be implemented without moving the sample by scanning the energy of the incident x-ray beam. This capability is made possible by introducing a 3D Fourier transform that accounts for x-ray wavelength variability. We demonstrate the approach by inverting coherent Bragg diffraction patterns from a gold nanocrystal measured with an x-ray energy scan. Variable-wavelength BCDI will expand the breadth of feasible in situ 3D strain imaging experiments towards more diverse materials environments, especially where sample manipulation is difficult.

Three Dimensional Variable-Wavelength X-Ray Bragg Coherent Diffraction Imaging.

PubMed

Cha, W; Ulvestad, A; Allain, M; Chamard, V; Harder, R; Leake, S J; Maser, J; Fuoss, P H; Hruszkewycz, S O

2016-11-25

We present and demonstrate a formalism by which three-dimensional (3D) Bragg x-ray coherent diffraction imaging (BCDI) can be implemented without moving the sample by scanning the energy of the incident x-ray beam. This capability is made possible by introducing a 3D Fourier transform that accounts for x-ray wavelength variability. We demonstrate the approach by inverting coherent Bragg diffraction patterns from a gold nanocrystal measured with an x-ray energy scan. Variable-wavelength BCDI will expand the breadth of feasible in situ 3D strain imaging experiments towards more diverse materials environments, especially where sample manipulation is difficult.

In-situ X-ray diffraction system using sources and detectors at fixed angular positions

DOEpatents

Gibson, David M [Voorheesville, NY; Gibson, Walter M [Voorheesville, NY; Huang, Huapeng [Latham, NY

2007-06-26

An x-ray diffraction technique for measuring a known characteristic of a sample of a material in an in-situ state. The technique includes using an x-ray source for emitting substantially divergent x-ray radiation--with a collimating optic disposed with respect to the fixed source for producing a substantially parallel beam of x-ray radiation by receiving and redirecting the divergent paths of the divergent x-ray radiation. A first x-ray detector collects radiation diffracted from the sample; wherein the source and detector are fixed, during operation thereof, in position relative to each other and in at least one dimension relative to the sample according to a-priori knowledge about the known characteristic of the sample. A second x-ray detector may be fixed relative to the first x-ray detector according to the a-priori knowledge about the known characteristic of the sample, especially in a phase monitoring embodiment of the present invention.

Synthesis and oxidation catalysis of [tris(oxazolinyl)borato]cobalt(II) scorpionates

DOE PAGES

Reinig, Regina R.; Mukherjee, Debabrata; Weinstein, Zachary B.; ...

2016-04-28

The reaction of CoCl 2·THF and thallium tris(4,4-dimethyl-2-oxazolinyl)phenylborate (TlTo M) in tetrahydrofuran (THF) provides To MCoCl (1) in 95 % yield; however, appropriate solvents and starting materials are required to favor 1 over two other readily formed side-products, (To M) 2Co (2) and {HTo M}CoCl 2 (3). ESR, NMR, FTIR, and UV/Vis spectroscopies were used to distinguish these cobalt(II) products and probe their electronic and structural properties. Even after the structures indicated by these methods were confirmed by X-ray crystallography, the spectroscopic identification of trace contaminants in the material was challenging. The recognition of possible contaminants in the synthesis ofmore » To MCoCl in combination with the paramagnetic nature of these complexes provided impetus for the utilization of X-ray powder diffraction to measure the purity of the To MCoCl bulk sample. Furthermore, the X-ray powder diffraction results provide support for the bulk-phase purity of To MCoCl in preparations that avoid 2 and 3. Thus, 1 is a precursor for new [tris(oxazolinyl)borato]cobalt chemistry, as exemplified by its reactions with KOtBu and NaOAc to give To MCoOtBu (4) and To MCoOAc (5), respectively. Compound 5 is a catalyst for the oxidation of cyclohexane with meta-chloroperoxybenzoic acid (mCPBA), and the rate constants and selectivity for cyclohexanol versus cyclohexanone and ϵ-caprolactone were assessed.« less

Statistical physics approaches to Alzheimer's disease

NASA Astrophysics Data System (ADS)

Peng, Shouyong

Alzheimer's disease (AD) is the most common cause of late life dementia. In the brain of an AD patient, neurons are lost and spatial neuronal organizations (microcolumns) are disrupted. An adequate quantitative analysis of microcolumns requires that we automate the neuron recognition stage in the analysis of microscopic images of human brain tissue. We propose a recognition method based on statistical physics. Specifically, Monte Carlo simulations of an inhomogeneous Potts model are applied for image segmentation. Unlike most traditional methods, this method improves the recognition of overlapped neurons, and thus improves the overall recognition percentage. Although the exact causes of AD are unknown, as experimental advances have revealed the molecular origin of AD, they have continued to support the amyloid cascade hypothesis, which states that early stages of aggregation of amyloid beta (Abeta) peptides lead to neurodegeneration and death. X-ray diffraction studies reveal the common cross-beta structural features of the final stable aggregates-amyloid fibrils. Solid-state NMR studies also reveal structural features for some well-ordered fibrils. But currently there is no feasible experimental technique that can reveal the exact structure or the precise dynamics of assembly and thus help us understand the aggregation mechanism. Computer simulation offers a way to understand the aggregation mechanism on the molecular level. Because traditional all-atom continuous molecular dynamics simulations are not fast enough to investigate the whole aggregation process, we apply coarse-grained models and discrete molecular dynamics methods to increase the simulation speed. First we use a coarse-grained two-bead (two beads per amino acid) model. Simulations show that peptides can aggregate into multilayer beta-sheet structures, which agree with X-ray diffraction experiments. To better represent the secondary structure transition happening during aggregation, we refine the model to four beads per amino acid. Typical essential interactions, such as backbone hydrogen bond, hydrophobic and electrostatic interactions, are incorporated into our model. We study the aggregation of Abeta16-22, a peptide that can aggregate into a well-ordered fibrillar structure in experiments. Our results show that randomly-oriented monomers can aggregate into fibrillar subunits, which agree not only with X-ray diffraction experiments but also with solid-state NMR studies. Our findings demonstrate that coarse-grained models and discrete molecular dynamics simulations can help researchers understand the aggregation mechanism of amyloid peptides.

Shape-dependent hydrogen-storage properties in Pd nanocrystals: which does hydrogen prefer, octahedron (111) or cube (100)?

PubMed

Li, Guangqin; Kobayashi, Hirokazu; Dekura, Shun; Ikeda, Ryuichi; Kubota, Yoshiki; Kato, Kenichi; Takata, Masaki; Yamamoto, Tomokazu; Matsumura, Syo; Kitagawa, Hiroshi

2014-07-23

Pd octahedrons and cubes enclosed by {111} and {100} facets, respectively, have been synthesized for investigation of the shape effect on hydrogen-absorption properties. Hydrogen-storage properties were investigated using in situ powder X-ray diffraction, in situ solid-state (2)H NMR and hydrogen pressure-composition isotherm measurements. With these measurements, it was found that the exposed facets do not affect hydrogen-storage capacity; however, they significantly affect the absorption speed, with octahedral nanocrystals showing the faster response. The heat of adsorption of hydrogen and the hydrogen diffusion pathway were suggested to be dominant factors for hydrogen-absorption speed. Furthermore, in situ solid-state (2)H NMR detected for the first time the state of (2)H in a solid-solution (Pd + H) phase of Pd nanocrystals at rt.

Carbonic anhydrase inhibition of Schiff base derivative of imino-methyl-naphthalen-2-ol: Synthesis, structure elucidation, molecular docking, dynamic simulation and density functional theory calculations

NASA Astrophysics Data System (ADS)

Abbas, Saghir; Nasir, Hafiza Huma; Zaib, Sumera; Ali, Saqib; Mahmood, Tariq; Ayub, Khurshid; Tahir, Muhammad Nawaz; Iqbal, Jamshed

2018-03-01

In the present study, we have designed and synthesized a Schiff base derivative 3 and characterized by FT-IR, 1H and 13C NMR spectroscopy. Single crystal X-ray diffraction and NMR studies were also performed. The synthetic compound was screened for its inhibitory potential against carbonic anhydrase II. The experimental results were validated by molecular docking and dynamic simulations of compound 3 in the active pocket of enzyme. Important binding interactions with the key residues in the active site of the carbonic anhydrase enzyme were revealed. Moreover, supramolecular assembly of the title compound was analyzed by density functional theory (DFT) calculations. These studies rendered a more clear understanding for the demonstration of novel molecular mechanism involved in CA II inhibition by the synthesized compound.

On the influence of ion exchange on the local structure of the titanosilicate ETS-10.

PubMed

Pavel, Claudiu C; Zibrowius, Bodo; Löffler, Elke; Schmidt, Wolfgang

2007-07-14

The effect of ion exchange with different monovalent cations (NH(4)(+), K(+), Na(+) and Cs(+)) on the local structure of the titanosilicate ETS-10 has been studied by (29)Si MAS NMR and Raman spectroscopy. Although X-ray diffraction shows no significant influence of ion exchange on the long range order, ammonium exchange is found to result in substantial damage to the local structure. Ion exchange experiments with alkali cations under significantly more acidic conditions clearly show that the structural damage brought about by ammonium exchange is not caused by the low pH of the exchange solution. The exchange with potassium and caesium ions also leads to significant changes in the (29)Si NMR and Raman spectra. However, these changes can largely be reversed by sodium back-exchange.

Pressure-Stabilized Cubic Perovskite Oxyhydride BaScO2H.

PubMed

Goto, Yoshihiro; Tassel, Cédric; Noda, Yasuto; Hernandez, Olivier; Pickard, Chris J; Green, Mark A; Sakaebe, Hikari; Taguchi, Noboru; Uchimoto, Yoshiharu; Kobayashi, Yoji; Kageyama, Hiroshi

2017-05-01

We report a scandium oxyhydride BaScO 2 H prepared by solid state reaction under high pressure. Rietveld refinements against powder synchrotron X-ray and neutron diffraction data revealed that BaScO 2 H adopts the ideal cubic perovskite structure (Pm3̅m), where oxide (O 2- ) and hydride (H - ) anions are disordered. 1 H nuclear magnetic resonance (NMR) spectroscopy provides a positive chemical shift of about +4.4 ppm, which can be understood by the distance to the nearest (and possibly the next nearest) cation from the H nucleus. A further analysis of the NMR data and calculations based on ab initio random structure searches suggest a partial cis preference in ScO 4 H 2 octahedra. The present oxyhydride, if compositionally or structurally tuned, may become a candidate for H - conductors.

The effect of exit beam phase aberrations on parallel beam coherent x-ray reconstructions

NASA Astrophysics Data System (ADS)

Hruszkewycz, S. O.; Harder, R.; Xiao, X.; Fuoss, P. H.

2010-12-01

Diffraction artifacts from imperfect x-ray windows near the sample are an important consideration in the design of coherent x-ray diffraction measurements. In this study, we used simulated and experimental diffraction patterns in two and three dimensions to explore the effect of phase imperfections in a beryllium window (such as a void or inclusion) on the convergence behavior of phasing algorithms and on the ultimate reconstruction. A predictive relationship between beam wavelength, sample size, and window position was derived to explain the dependence of reconstruction quality on beryllium defect size. Defects corresponding to this prediction cause the most damage to the sample exit wave and induce signature error oscillations during phasing that can be used as a fingerprint of experimental x-ray window artifacts. The relationship between x-ray window imperfection size and coherent x-ray diffractive imaging reconstruction quality explored in this work can play an important role in designing high-resolution in situ coherent imaging instrumentation and will help interpret the phasing behavior of coherent diffraction measured in these in situ environments.

The effect of exit beam phase aberrations on parallel beam coherent x-ray reconstructions.

PubMed

Hruszkewycz, S O; Harder, R; Xiao, X; Fuoss, P H

2010-12-01

Diffraction artifacts from imperfect x-ray windows near the sample are an important consideration in the design of coherent x-ray diffraction measurements. In this study, we used simulated and experimental diffraction patterns in two and three dimensions to explore the effect of phase imperfections in a beryllium window (such as a void or inclusion) on the convergence behavior of phasing algorithms and on the ultimate reconstruction. A predictive relationship between beam wavelength, sample size, and window position was derived to explain the dependence of reconstruction quality on beryllium defect size. Defects corresponding to this prediction cause the most damage to the sample exit wave and induce signature error oscillations during phasing that can be used as a fingerprint of experimental x-ray window artifacts. The relationship between x-ray window imperfection size and coherent x-ray diffractive imaging reconstruction quality explored in this work can play an important role in designing high-resolution in situ coherent imaging instrumentation and will help interpret the phasing behavior of coherent diffraction measured in these in situ environments.

Femtosecond X-ray Diffraction From Two-Dimensional Protein Crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frank, Matthias; Carlson, David B.; Hunter, Mark

2014-02-28

Here we present femtosecond x-ray diffraction patterns from two-dimensional (2-D) protein crystals using an x-ray free electron laser (XFEL). To date it has not been possible to acquire x-ray diffraction from individual 2-D protein crystals due to radiation damage. However, the intense and ultrafast pulses generated by an XFEL permits a new method of collecting diffraction data before the sample is destroyed. Utilizing a diffract-before-destroy methodology at the Linac Coherent Light Source, we observed Bragg diffraction to better than 8.5 Å resolution for two different 2-D protein crystal samples that were maintained at room temperature. These proof-of-principle results show promisemore » for structural analysis of both soluble and membrane proteins arranged as 2-D crystals without requiring cryogenic conditions or the formation of three-dimensional crystals.« less

Influence of gamma ray irradiation on stoichiometry of hydrothermally synthesized bismuth telluride nanoparticles

NASA Astrophysics Data System (ADS)

Abishek, N. S.; Naik, K. Gopalakrishna

2018-05-01

Bismuth telluride (Bi2Te3) nanoparticles were synthesized by the hydrothermal method at 200 °C for 24 h. The synthesized Bi2Te3 nanoparticles were irradiated with gamma rays at doses of 50 kGy and 100 kGy. The structural characterization of the pre-irradiated and post-irradiated samples was carried out by X-ray diffraction technique and was found to have rhombohedral phase having R3 ¯m (166) space group. The X-ray diffraction peaks were found to shift towards lower diffraction angle with gamma ray irradiation. The morphologies and compositions of the grown Bi2Te3 nanoparticles were studied using Field Emission Scanning Electron Microscope and X-ray energy dispersive analysis, respectively. The possible cause for the shift in the X-ray diffraction peaks with gamma ray irradiation has been discussed in the present work.

High Power Optical Coatings by Atomic Layer Deposition and Signatures of Laser-Induced Damage

DTIC Science & Technology

2012-08-28

diffraction angle 0 into crystal lattice spacing d by the Bragg condition, mX = 2d sin 0. Here X is the x - ray wavelength... angle x - ray diffraction (GAXRD) measurements, which were made at a fixed shallow incidence angle of 0.5°. Detector scans were done to measure the...was finished with 200 hafnia cycles m the fmal half period rather than 400. Crystallinity was measured by x - ray diffraction (XRD) with

Penifupyrone, a new cytotoxic funicone derivative from the endophytic fungus Penicillium sp. HSZ-43.

PubMed

Chen, Ming-Jun; Fu, Yang-Wu; Zhou, Qun-Ying

2014-01-01

Penifupyrone (1), a new funicone derivative, has been isolated from the endophytic fungus Penicillium sp. HSZ-43, along with three known analogues, funicone (2), deoxyfunicone (3) and 3-O-methylfunicone (4). These structures were identified by using spectroscopic methods, including UV, MS, 1D and 2D NMR experiments. The structure of 1 was confirmed by single-crystal X-ray diffraction analysis. All the isolated compounds were evaluated for cytotoxicity against human oral epidermoid carcinoma KB cells, and compound 1 exhibited moderate cytotoxic activity with IC50 value of 4.7 μM.

Trichorenins A-C, Algicidal Tetracyclic Metabolites from the Marine-Alga-Epiphytic Fungus Trichoderma virens Y13-3.

PubMed

Shi, Zhen-Zhen; Miao, Feng-Ping; Fang, Sheng-Tao; Yin, Xiu-Li; Ji, Nai-Yun

2018-04-27

Three novel polyketide-like metabolites, trichorenins A-C (1-3), with a unique tetracyclic carbon skeleton were obtained from the culture of Trichoderma virens Y13-3, an epiphyte of the marine red alga Gracilaria vermiculophylla. Their structures and relative configurations were established by analysis of 1D/2D NMR and MS data, and their absolute configurations were unequivocally assigned by X-ray diffraction and ECD spectra aided by quantum chemical calculations. Compounds 1-3 exhibited potent inhibition against two marine phytoplankton species, Chattonella marina and Karlodinium veneficum.

Ligubenzocycloheptanone A, a Novel Tricyclic Butenolide with a 6/7/5 Skeleton from Ligusticum chuanxiong

PubMed Central

Han, Bing; Zhang, Xu; Feng, Zi-Ming; Jiang, Jian-Shuang; Li, Li; Yang, Ya-Nan; Zhang, Pei-Cheng

2016-01-01

Ligubenzocycloheptanone A (1), a novel tricyclic butenolide with a 6/7/5-membered ring skeleton, was isolated from the rhizome of Ligusticum chuanxiong. Its unusual structure was determined using UV, IR, HRESIMS, 1D and 2D NMR data, X-ray diffraction crystallography and by the comparison of experimental and calculated electronic circular dichroism (ECD) spectra. 1 possessed a benzocycloheptanone core featuring butyrolactone, which is rarely observed in nature. A possible biosynthetic pathway was proposed. Ligubenzocycloheptanone A showed strong radical scavenging activity with an IC50 value of 2.3 μM. PMID:27461841

Ion mobility and transport properties of bismuth fluoride-containing solid solutions with tysonite-type structure

NASA Astrophysics Data System (ADS)

Kavun, V. Ya.; Uvarov, N. F.; Slobodyuk, A. B.; Merkulov, E. B.; Polyantsev, M. M.

2018-07-01

The ion mobility and conductivity of solid solutions with tysonite-type structure obtained by doping bismuth trifluoride with lead (II) fluoride, and zirconium and bismuth oxides have been studied using 19F NMR, X-ray diffraction analysis, and impedance spectroscopy. The types of ionic motions in the fluoride sublattice of the synthesized solid solutions in the temperature range 150-450 K have been determined and the energy of their activation has been estimated. Due to high ionic conductivity, above 10-2 S/cm at 570 K, these solid solutions can be considered as superionic conductors.

Crystal Structure of 8β-Hydroxyeremophil-7(11)-ene-12,8α(4β,6α)-diolide

NASA Astrophysics Data System (ADS)

Xue, Hui-qing; Xue, Hui-feng; Wu, Biao; Wang, Han-qing; Xin, Xue-lei; Wu, Shui-xian

2006-12-01

8β-Hydroxyeremophil-7(11)-ene-12,8α(4β,6α)-diolide was isolated from the Ligularia intermedia and characterized by MS, multi NMR and X-ray single crystal diffraction. Its crystal structure was determined as in a orthorhombic type, with space group P212121 with a=6.8519(5), b=10.7191(8), c=18.5942(14) Å, V =1365.67(18) Å3, Z=4, and the calculated density is 1.354 mg/m3. F(000)=592, µ=0.101 mm-1.

Dimeric Matrine-Type Alkaloids from the Roots of Sophora flavescens and Their Anti-Hepatitis B Virus Activities.

PubMed

Zhang, Yu-Bo; Zhan, Li-Qin; Li, Guo-Qiang; Wang, Feng; Wang, Ying; Li, Yao-Lan; Ye, Wen-Cai; Wang, Guo-Cai

2016-08-05

Six unusual matrine-type alkaloid dimers, flavesines A-F (1-6, respectively), together with three proposed biosynthetic intermediates (7-9) were isolated from the roots of Sophora flavescens. Compounds 1-5 were the first natural matrine-type alkaloid dimers, and compound 6 represented an unprecedented dimerization pattern constructed by matrine and (-)-cytisine. Their structures were elucidated by NMR, MS, single-crystal X-ray diffraction, and a chemical method. The hypothetical biogenetic pathways of 1-6 were also proposed. Compounds 1-9 exhibited inhibitory activities against hepatitis B virus.

Selective conversion of {Mo132} Keplerate ion into 4-electron reduced crown-capped Keggin derivative [Te5Mo15O57](8-). A key intermediate to single-phase M1 multielement MoVTeO light-alkanes oxidation catalyst.

PubMed

Canioni, Romain; Marchal-Roch, Catherine; Leclerc-Laronze, Nathalie; Haouas, Mohamed; Taulèlle, Francis; Marrot, Jérôme; Paul, Sebastien; Lamonier, Carole; Paul, Jean-François; Loridant, Stéphane; Millet, Jean-Marc M; Cadot, Emmanuel

2011-06-14

{Mo(132)} Keplerate anion reacts with tellurites to give a soluble precursor to produce in hydrothermal conditions single-phase M1 MoVTeO light-alkanes oxidation catalyst. Characterization of this Te-containing intermediate by single-crystal X-ray diffraction, (125)Te NMR, UV-visible and redox titration reveals a molybdotellurite anion as a crown-capped Keggin derivative. This journal is © The Royal Society of Chemistry 2011

Two new sesquiterpenoids produced by halophilic Nocardiopsis chromatogenes YIM 90109.

PubMed

Sun, Ming-Wei; Zhang, Xiao-Mei; Bi, Hui-Li; Li, Wen-Jun; Lu, Chun-Hua

2017-01-01

Two new germacradiene-type sesquiterpenoids, including 1(10)E,5E-germacradiene-9β,11-diol (or 9β-hydroxyl germacradienol) (1) and 11-hydroxy-1(10)E,5E-germacradien-2-one (2-oxygermacradienol) (2), together with a known geosmin-type sesquiterpenoid (1β,4β,4aβ,7α,8aα)-4,8a-dimethyloctahydronaphthalene-1,4a,7(2H)-triol (3), were elucidated by their NMR spectroscopic data, HR-ESI-MS and single-crystal X-ray diffraction from the halophilic strain Nocardiopsis chromatogenes YIM 90109. The antimicrobial activities were evaluated by paper diffusion method.

Mollolide A, a diterpenoid with a new 1,10:2,3-disecograyanane skeleton from the roots of Rhododendron molle.

PubMed

Li, Yong; Liu, Yun-Bao; Zhang, Jian-Jun; Li, Yu-Huan; Jiang, Jian-Dong; Yu, Shi-Shan; Ma, Shuang-Gang; Qu, Jing; Lv, Hai-Ning

2013-06-21

Mollolide A (1), a diterpenoid featuring a new 1,10:2,3-disecograyanane skeleton, was isolated from the roots of Rhododendron molle. Its structure was elucidated through extensive MS, IR, and NMR spectroscopy analyses. The absolute configuration was determined by single-crystal X-ray diffraction of its p-bromobenzoate derivative (1b). Compound 1 exhibits a significant analgesic effect at a dose of 20 mg/kg and antiviral activity against the Coxsackie B3 virus with an IC50 value of 27.7 μM.

Structural studies of 4-aminoantipyrine derivatives

NASA Astrophysics Data System (ADS)

Cunha, Silvio; Oliveira, Shana M.; Rodrigues, Manoel T.; Bastos, Rodrigo M.; Ferrari, Jailton; de Oliveira, Cecília M. A.; Kato, Lucília; Napolitano, Hamilton B.; Vencato, Ivo; Lariucci, Carlito

2005-10-01

Reaction of 4-aminoantipyrine with acetylacetone, ethyl acetoacetate, benzoyl isothiocyanate, phenyl isothiocyanate, maleic anhydride and methoxymethylene Meldrum's acid afforded a series of new antipyrine derivatives. The antibacterial activity of the synthesized compounds against Micrococcus luteus ATCC 9341, Staphilococcus aureus ATCC 29737, and Escherichia coli ATCC 8739 was evaluated and the minimal inhibitory concentration determined. Modest activity was found only to the maleamic acid obtained from the reaction of 4-aminoantipyrine and maleic anhydride. 1H NMR investigation of this maleamic acid showed that it is slowly converted to the corresponding toxic maleimide. The structures of three derivatives were determined by X-ray diffraction analysis.

Materials identification using a small-scale pixellated x-ray diffraction system

NASA Astrophysics Data System (ADS)

O'Flynn, D.; Crews, C.; Drakos, I.; Christodoulou, C.; Wilson, M. D.; Veale, M. C.; Seller, P.; Speller, R. D.

2016-05-01

A transmission x-ray diffraction system has been developed using a pixellated, energy-resolving detector (HEXITEC) and a small-scale, mains operated x-ray source (Amptek Mini-X). HEXITEC enables diffraction to be measured without the requirement of incident spectrum filtration, or collimation of the scatter from the sample, preserving a large proportion of the useful signal compared with other diffraction techniques. Due to this efficiency, sufficient molecular information for material identification can be obtained within 5 s despite the relatively low x-ray source power. Diffraction data are presented from caffeine, hexamine, paracetamol, plastic explosives and narcotics. The capability to determine molecular information from aspirin tablets inside their packaging is demonstrated. Material selectivity and the potential for a sample classification model is shown with principal component analysis, through which each different material can be clearly resolved.

Dynamic X-ray diffraction sampling for protein crystal positioning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scarborough, Nicole M.; Godaliyadda, G. M. Dilshan P.; Ye, Dong Hye

A sparse supervised learning approach for dynamic sampling (SLADS) is described for dose reduction in diffraction-based protein crystal positioning. Crystal centering is typically a prerequisite for macromolecular diffraction at synchrotron facilities, with X-ray diffraction mapping growing in popularity as a mechanism for localization. In X-ray raster scanning, diffraction is used to identify the crystal positions based on the detection of Bragg-like peaks in the scattering patterns; however, this additional X-ray exposure may result in detectable damage to the crystal prior to data collection. Dynamic sampling, in which preceding measurements inform the next most information-rich location to probe for image reconstruction,more » significantly reduced the X-ray dose experienced by protein crystals during positioning by diffraction raster scanning. The SLADS algorithm implemented herein is designed for single-pixel measurements and can select a new location to measure. In each step of SLADS, the algorithm selects the pixel, which, when measured, maximizes the expected reduction in distortion given previous measurements. Ground-truth diffraction data were obtained for a 5 µm-diameter beam and SLADS reconstructed the image sampling 31% of the total volume and only 9% of the interior of the crystal greatly reducing the X-ray dosage on the crystal. Furthermore, by usingin situtwo-photon-excited fluorescence microscopy measurements as a surrogate for diffraction imaging with a 1 µm-diameter beam, the SLADS algorithm enabled image reconstruction from a 7% sampling of the total volume and 12% sampling of the interior of the crystal. When implemented into the beamline at Argonne National Laboratory, without ground-truth images, an acceptable reconstruction was obtained with 3% of the image sampled and approximately 5% of the crystal. The incorporation of SLADS into X-ray diffraction acquisitions has the potential to significantly minimize the impact of X-ray exposure on the crystal by limiting the dose and area exposed for image reconstruction and crystal positioning using data collection hardware present in most macromolecular crystallography end-stations.« less

Dynamic X-ray diffraction sampling for protein crystal positioning

DOE PAGES

Scarborough, Nicole M.; Godaliyadda, G. M. Dilshan P.; Ye, Dong Hye; ...

2017-01-01

A sparse supervised learning approach for dynamic sampling (SLADS) is described for dose reduction in diffraction-based protein crystal positioning. Crystal centering is typically a prerequisite for macromolecular diffraction at synchrotron facilities, with X-ray diffraction mapping growing in popularity as a mechanism for localization. In X-ray raster scanning, diffraction is used to identify the crystal positions based on the detection of Bragg-like peaks in the scattering patterns; however, this additional X-ray exposure may result in detectable damage to the crystal prior to data collection. Dynamic sampling, in which preceding measurements inform the next most information-rich location to probe for image reconstruction,more » significantly reduced the X-ray dose experienced by protein crystals during positioning by diffraction raster scanning. The SLADS algorithm implemented herein is designed for single-pixel measurements and can select a new location to measure. In each step of SLADS, the algorithm selects the pixel, which, when measured, maximizes the expected reduction in distortion given previous measurements. Ground-truth diffraction data were obtained for a 5 µm-diameter beam and SLADS reconstructed the image sampling 31% of the total volume and only 9% of the interior of the crystal greatly reducing the X-ray dosage on the crystal. Furthermore, by usingin situtwo-photon-excited fluorescence microscopy measurements as a surrogate for diffraction imaging with a 1 µm-diameter beam, the SLADS algorithm enabled image reconstruction from a 7% sampling of the total volume and 12% sampling of the interior of the crystal. When implemented into the beamline at Argonne National Laboratory, without ground-truth images, an acceptable reconstruction was obtained with 3% of the image sampled and approximately 5% of the crystal. The incorporation of SLADS into X-ray diffraction acquisitions has the potential to significantly minimize the impact of X-ray exposure on the crystal by limiting the dose and area exposed for image reconstruction and crystal positioning using data collection hardware present in most macromolecular crystallography end-stations.« less

Dynamic X-ray diffraction sampling for protein crystal positioning

PubMed Central

Scarborough, Nicole M.; Godaliyadda, G. M. Dilshan P.; Ye, Dong Hye; Kissick, David J.; Zhang, Shijie; Newman, Justin A.; Sheedlo, Michael J.; Chowdhury, Azhad U.; Fischetti, Robert F.; Das, Chittaranjan; Buzzard, Gregery T.; Bouman, Charles A.; Simpson, Garth J.

2017-01-01

A sparse supervised learning approach for dynamic sampling (SLADS) is described for dose reduction in diffraction-based protein crystal positioning. Crystal centering is typically a prerequisite for macromolecular diffraction at synchrotron facilities, with X-ray diffraction mapping growing in popularity as a mechanism for localization. In X-ray raster scanning, diffraction is used to identify the crystal positions based on the detection of Bragg-like peaks in the scattering patterns; however, this additional X-ray exposure may result in detectable damage to the crystal prior to data collection. Dynamic sampling, in which preceding measurements inform the next most information-rich location to probe for image reconstruction, significantly reduced the X-ray dose experienced by protein crystals during positioning by diffraction raster scanning. The SLADS algorithm implemented herein is designed for single-pixel measurements and can select a new location to measure. In each step of SLADS, the algorithm selects the pixel, which, when measured, maximizes the expected reduction in distortion given previous measurements. Ground-truth diffraction data were obtained for a 5 µm-diameter beam and SLADS reconstructed the image sampling 31% of the total volume and only 9% of the interior of the crystal greatly reducing the X-ray dosage on the crystal. Using in situ two-photon-excited fluorescence microscopy measurements as a surrogate for diffraction imaging with a 1 µm-diameter beam, the SLADS algorithm enabled image reconstruction from a 7% sampling of the total volume and 12% sampling of the interior of the crystal. When implemented into the beamline at Argonne National Laboratory, without ground-truth images, an acceptable reconstruction was obtained with 3% of the image sampled and approximately 5% of the crystal. The incorporation of SLADS into X-ray diffraction acquisitions has the potential to significantly minimize the impact of X-ray exposure on the crystal by limiting the dose and area exposed for image reconstruction and crystal positioning using data collection hardware present in most macromolecular crystallography end-stations. PMID:28009558

Dynamic X-ray diffraction sampling for protein crystal positioning.

PubMed

Scarborough, Nicole M; Godaliyadda, G M Dilshan P; Ye, Dong Hye; Kissick, David J; Zhang, Shijie; Newman, Justin A; Sheedlo, Michael J; Chowdhury, Azhad U; Fischetti, Robert F; Das, Chittaranjan; Buzzard, Gregery T; Bouman, Charles A; Simpson, Garth J

2017-01-01

A sparse supervised learning approach for dynamic sampling (SLADS) is described for dose reduction in diffraction-based protein crystal positioning. Crystal centering is typically a prerequisite for macromolecular diffraction at synchrotron facilities, with X-ray diffraction mapping growing in popularity as a mechanism for localization. In X-ray raster scanning, diffraction is used to identify the crystal positions based on the detection of Bragg-like peaks in the scattering patterns; however, this additional X-ray exposure may result in detectable damage to the crystal prior to data collection. Dynamic sampling, in which preceding measurements inform the next most information-rich location to probe for image reconstruction, significantly reduced the X-ray dose experienced by protein crystals during positioning by diffraction raster scanning. The SLADS algorithm implemented herein is designed for single-pixel measurements and can select a new location to measure. In each step of SLADS, the algorithm selects the pixel, which, when measured, maximizes the expected reduction in distortion given previous measurements. Ground-truth diffraction data were obtained for a 5 µm-diameter beam and SLADS reconstructed the image sampling 31% of the total volume and only 9% of the interior of the crystal greatly reducing the X-ray dosage on the crystal. Using in situ two-photon-excited fluorescence microscopy measurements as a surrogate for diffraction imaging with a 1 µm-diameter beam, the SLADS algorithm enabled image reconstruction from a 7% sampling of the total volume and 12% sampling of the interior of the crystal. When implemented into the beamline at Argonne National Laboratory, without ground-truth images, an acceptable reconstruction was obtained with 3% of the image sampled and approximately 5% of the crystal. The incorporation of SLADS into X-ray diffraction acquisitions has the potential to significantly minimize the impact of X-ray exposure on the crystal by limiting the dose and area exposed for image reconstruction and crystal positioning using data collection hardware present in most macromolecular crystallography end-stations.

Fixture for supporting and aligning a sample to be analyzed in an x-ray diffraction apparatus

DOEpatents

Green, L.A.; Heck, J.L. Jr.

1985-04-23

A fixture is provided for supporting and aligning small samples of material on a goniometer for x-ray diffraction analysis. A sample-containing capillary is accurately positioned for rotation in the x-ray beam by selectively adjusting the fixture to position the capillary relative to the x and y axes thereof to prevent wobble and position the sample along the z axis or the axis of rotation. By employing the subject fixture relatively small samples of materials can be analyzed in an x-ray diffraction apparatus previously limited to the analysis of much larger samples.

Fixture for supporting and aligning a sample to be analyzed in an X-ray diffraction apparatus

DOEpatents

Green, Lanny A.; Heck, Jr., Joaquim L.

1987-01-01

A fixture is provided for supporting and aligning small samples of material on a goniometer for X-ray diffraction analysis. A sample-containing capillary is accurately positioned for rotation in the X-ray beam by selectively adjusting the fixture to position the capillary relative to the x and y axes thereof to prevent wobble and position the sample along the z axis or the axis of rotation. By employing the subject fixture relatively small samples of materials can be analyzed in an X-ray diffraction apparatus previously limited to the analysis of much larger samples.

JMFA2—a graphically interactive Java program that fits microfibril angle X-ray diffraction data

Treesearch

Steve P. Verrill; David E. Kretschmann; Victoria L. Herian

2006-01-01

X-ray diffraction techniques have the potential to decrease the time required to determine microfibril angles dramatically. In this paper, we discuss the latest version of a curve-fitting toll that permits us to reduce the time required to evaluate MFA X-ray diffraction patterns. Further, because this tool reflects the underlying physics more accurately than existing...

A high-transparency, micro-patternable chip for X-ray diffraction analysis of microcrystals under native growth conditions

DOE PAGES

Murray, Thomas D.; Lyubimov, Artem Y.; Ogata, Craig M.; ...

2015-08-11

Microcrystals present a significant impediment to the determination of macromolecular structures by X-ray diffraction methods. Although microfocus synchrotron beamlines and X-ray free-electron lasers (XFELs) can enable the collection of interpretable diffraction data from microcrystals, there is a need for efficient methods of harvesting small volumes (<2 µl) of microcrystals grown under common laboratory formats and delivering them to an X-ray beam source under native growth conditions. One approach that shows promise in overcoming the challenges intrinsic to microcrystal analysis is to pair so-called `fixed-target' sample-delivery devices with microbeam-based X-ray diffraction methods. However, to record weak diffraction patterns it is necessarymore » to fabricate devices from X-ray-transparent materials that minimize background scattering. Presented here is the design of a new micro-diffraction device consisting of three layers fabricated from silicon nitride, photoresist and polyimide film. The chip features low X-ray scattering and X-ray absorption properties, and uses a customizable blend of hydrophobic and hydrophilic surface patterns to help localize microcrystals to defined regions. Microcrystals in their native growth conditions can be loaded into the chips with a standard pipette, allowing data collection at room temperature. Diffraction data collected from hen egg-white lysozyme microcrystals (10–15 µm) loaded into the chips yielded a complete, high-resolution (<1.6 Å) data set sufficient to determine a high-quality structure by molecular replacement. In addition, the features of the chip allow the rapid and user-friendly analysis of microcrystals grown under virtually any laboratory format at microfocus synchrotron beamlines and XFELs.« less

A high-transparency, micro-patternable chip for X-ray diffraction analysis of microcrystals under native growth conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murray, Thomas D.; Lyubimov, Artem Y.; Ogata, Craig M.

Microcrystals present a significant impediment to the determination of macromolecular structures by X-ray diffraction methods. Although microfocus synchrotron beamlines and X-ray free-electron lasers (XFELs) can enable the collection of interpretable diffraction data from microcrystals, there is a need for efficient methods of harvesting small volumes (<2 µl) of microcrystals grown under common laboratory formats and delivering them to an X-ray beam source under native growth conditions. One approach that shows promise in overcoming the challenges intrinsic to microcrystal analysis is to pair so-called `fixed-target' sample-delivery devices with microbeam-based X-ray diffraction methods. However, to record weak diffraction patterns it is necessarymore » to fabricate devices from X-ray-transparent materials that minimize background scattering. Presented here is the design of a new micro-diffraction device consisting of three layers fabricated from silicon nitride, photoresist and polyimide film. The chip features low X-ray scattering and X-ray absorption properties, and uses a customizable blend of hydrophobic and hydrophilic surface patterns to help localize microcrystals to defined regions. Microcrystals in their native growth conditions can be loaded into the chips with a standard pipette, allowing data collection at room temperature. Diffraction data collected from hen egg-white lysozyme microcrystals (10–15 µm) loaded into the chips yielded a complete, high-resolution (<1.6 Å) data set sufficient to determine a high-quality structure by molecular replacement. In addition, the features of the chip allow the rapid and user-friendly analysis of microcrystals grown under virtually any laboratory format at microfocus synchrotron beamlines and XFELs.« less

A high-transparency, micro-patternable chip for X-ray diffraction analysis of microcrystals under native growth conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murray, Thomas D.; Lyubimov, Artem Y.; Ogata, Craig M.

Microcrystals present a significant impediment to the determination of macromolecular structures by X-ray diffraction methods. Although microfocus synchrotron beamlines and X-ray free-electron lasers (XFELs) can enable the collection of interpretable diffraction data from microcrystals, there is a need for efficient methods of harvesting small volumes (<2µl) of microcrystals grown under common laboratory formats and delivering them to an X-ray beam source under native growth conditions. One approach that shows promise in overcoming the challenges intrinsic to microcrystal analysis is to pair so-called `fixed-target' sample-delivery devices with microbeam-based X-ray diffraction methods. However, to record weak diffraction patterns it is necessary tomore » fabricate devices from X-ray-transparent materials that minimize background scattering. Presented here is the design of a new micro-diffraction device consisting of three layers fabricated from silicon nitride, photoresist and polyimide film. The chip features low X-ray scattering and X-ray absorption properties, and uses a customizable blend of hydrophobic and hydrophilic surface patterns to help localize microcrystals to defined regions. Microcrystals in their native growth conditions can be loaded into the chips with a standard pipette, allowing data collection at room temperature. Diffraction data collected from hen egg-white lysozyme microcrystals (10–15µm) loaded into the chips yielded a complete, high-resolution (<1.6Å) data set sufficient to determine a high-quality structure by molecular replacement. The features of the chip allow the rapid and user-friendly analysis of microcrystals grown under virtually any laboratory format at microfocus synchrotron beamlines and XFELs.« less

A high-transparency, micro-patternable chip for X-ray diffraction analysis of microcrystals under native growth conditions

PubMed Central

Murray, Thomas D.; Lyubimov, Artem Y.; Ogata, Craig M.; Vo, Huy; Uervirojnangkoorn, Monarin; Brunger, Axel T.; Berger, James M.

2015-01-01

Microcrystals present a significant impediment to the determination of macromolecular structures by X-ray diffraction methods. Although microfocus synchrotron beamlines and X-ray free-electron lasers (XFELs) can enable the collection of interpretable diffraction data from microcrystals, there is a need for efficient methods of harvesting small volumes (<2 µl) of microcrystals grown under common laboratory formats and delivering them to an X-ray beam source under native growth conditions. One approach that shows promise in overcoming the challenges intrinsic to microcrystal analysis is to pair so-called ‘fixed-target’ sample-delivery devices with microbeam-based X-ray diffraction methods. However, to record weak diffraction patterns it is necessary to fabricate devices from X-ray-transparent materials that minimize background scattering. Presented here is the design of a new micro-diffraction device consisting of three layers fabricated from silicon nitride, photoresist and polyimide film. The chip features low X-ray scattering and X-ray absorption properties, and uses a customizable blend of hydrophobic and hydrophilic surface patterns to help localize microcrystals to defined regions. Microcrystals in their native growth conditions can be loaded into the chips with a standard pipette, allowing data collection at room temperature. Diffraction data collected from hen egg-white lysozyme microcrystals (10–15 µm) loaded into the chips yielded a complete, high-resolution (<1.6 Å) data set sufficient to determine a high-quality structure by molecular replacement. The features of the chip allow the rapid and user-friendly analysis of microcrystals grown under virtually any laboratory format at microfocus synchrotron beamlines and XFELs. PMID:26457423

NMR and X-ray structural characterization and conformational aspects of fluorinated (5Z)-3-benzil-5-arylidenofuran-2(5H)-ones

NASA Astrophysics Data System (ADS)

Teixeira, R. R.; Barbosa, L. C. A.; Kabeshov, M. A.; Maltha, C. R. A.; Corrêa, R. S.; Doriguetto, A. C.

2014-10-01

Herein we describe structural insights of (5Z)-3-benzyl-5-(2-fluorobenzylidene)furan-2(5H)-one (6) and (5Z)-3-benzyl-5-(pentafluorobenzylidene)furan-2(5H)-one (7), γ-alkylidenebutenolides analogues of the natural products nostoclides. Their structures were investigated by NMR spectroscopy and X-ray crystallography. The stereochemistry of the exocyclic double bond of these fluorinated compounds was determined to be Z by NMR analysis and confirmed by X-ray data. Compounds 6 and 7 crystallized in the monoclinic crystal system P21/c group. A comparison between structural features of (6) and (7) and nostoclide derivatives previously published by us is described.

High-resolution x-ray diffraction microscopy of specifically labeled yeast cells

PubMed Central

Nelson, Johanna; Huang, Xiaojing; Steinbrener, Jan; Shapiro, David; Kirz, Janos; Marchesini, Stefano; Neiman, Aaron M.; Turner, Joshua J.; Jacobsen, Chris

2010-01-01

X-ray diffraction microscopy complements other x-ray microscopy methods by being free of lens-imposed radiation dose and resolution limits, and it allows for high-resolution imaging of biological specimens too thick to be viewed by electron microscopy. We report here the highest resolution (11–13 nm) x-ray diffraction micrograph of biological specimens, and a demonstration of molecular-specific gold labeling at different depths within cells via through-focus propagation of the reconstructed wavefield. The lectin concanavalin A conjugated to colloidal gold particles was used to label the α-mannan sugar in the cell wall of the yeast Saccharomyces cerevisiae. Cells were plunge-frozen in liquid ethane and freeze-dried, after which they were imaged whole using x-ray diffraction microscopy at 750 eV photon energy. PMID:20368463

High-resolution x-ray diffraction microscopy of specifically labeled yeast cells

DOE PAGES

Nelson, Johanna; Huang, Xiaojing; Steinbrener, Jan; ...

2010-04-20

X-ray diffraction microscopy complements other x-ray microscopy methods by being free of lens-imposed radiation dose and resolution limits, and it allows for high-resolution imaging of biological specimens too thick to be viewed by electron microscopy. We report here the highest resolution (11-13 nm) x-ray diffraction micrograph of biological specimens, and a demonstration of molecular-specific gold labeling at different depths within cells via through-focus propagation of the reconstructed wavefield. The lectin concanavalin A conjugated to colloidal gold particles was used to label the α-mannan sugar in the cell wall of the yeast Saccharomyces cerevisiae. Cells were plunge-frozen in liquid ethane andmore » freeze-dried, after which they were imaged whole using x-ray diffraction microscopy at 750 eV photon energy.« less

Coherent x-ray zoom condenser lens for diffractive and scanning microscopy.

PubMed

Kimura, Takashi; Matsuyama, Satoshi; Yamauchi, Kazuto; Nishino, Yoshinori

2013-04-22

We propose a coherent x-ray zoom condenser lens composed of two-stage deformable Kirkpatrick-Baez mirrors. The lens delivers coherent x-rays with a controllable beam size, from one micrometer to a few tens of nanometers, at a fixed focal position. The lens is suitable for diffractive and scanning microscopy. We also propose non-scanning coherent diffraction microscopy for extended objects by using an apodized focused beam produced by the lens with a spatial filter. The proposed apodized-illumination method will be useful in highly efficient imaging with ultimate storage ring sources, and will also open the way to single-shot coherent diffraction microscopy of extended objects with x-ray free-electron lasers.

Scanning force microscope for in situ nanofocused X-ray diffraction studies

PubMed Central

Ren, Zhe; Mastropietro, Francesca; Davydok, Anton; Langlais, Simon; Richard, Marie-Ingrid; Furter, Jean-Jacques; Thomas, Olivier; Dupraz, Maxime; Verdier, Marc; Beutier, Guillaume; Boesecke, Peter; Cornelius, Thomas W.

2014-01-01

A compact scanning force microscope has been developed for in situ combination with nanofocused X-ray diffraction techniques at third-generation synchrotron beamlines. Its capabilities are demonstrated on Au nano-islands grown on a sapphire substrate. The new in situ device allows for in situ imaging the sample topography and the crystallinity by recording simultaneously an atomic force microscope (AFM) image and a scanning X-ray diffraction map of the same area. Moreover, a selected Au island can be mechanically deformed using the AFM tip while monitoring the deformation of the atomic lattice by nanofocused X-ray diffraction. This in situ approach gives access to the mechanical behavior of nanomaterials. PMID:25178002

Synthesis, X-ray crystallography characterization, vibrational spectroscopic, molecular electrostatic potential maps, thermodynamic properties studies of N,N'-di(p-thiazole)formamidine.

PubMed

Rofouei, M K; Fereyduni, E; Sohrabi, N; Shamsipur, M; Attar Gharamaleki, J; Sundaraganesan, N

2011-01-01

In this work, we will report a combined experimental and theoretical study on molecular and vibrational structure of N,N'-di(p-thiazole)formamidine (DpTF). DpTF has been synthesized and characterized by elemental analysis, FT-IR, FT-Raman, 1H NMR, 13C NMR spectroscopy and X-ray single crystal diffraction. The FT-IR and FT-Raman spectra of DpTF were recorded in the solid phase. The optimized geometry was calculated by HF and B3LYP methods using 6-31G(d) basis set. The FT-IR and FT-Raman spectra of DpTF was calculated at the HF/B3LYP/6-31G(d) level and were interpreted in terms of potential energy distribution (PED) analysis. The scaled theoretical wavenumber showed very good agreement with the experimental values. A detailed interpretation of the infrared and Raman spectra of DpTF was reported. On the basis of vibrational analyses, the thermodynamic properties of the title compound at different temperatures have been calculated, revealing the correlations between Cp,m°, Sm°, Hm° and temperatures. Furthermore, molecular electrostatic potential maps (MESP) and total dipole moment properties of the compound have been calculated. Copyright © 2010 Elsevier B.V. All rights reserved.

Physicochemical characterization of novel Schiff bases derived from developed bacterial cellulose 2,3-dialdehyde.

PubMed

Keshk, Sherif M A S; Ramadan, Ahmed M; Bondock, Samir

2015-08-20

The synthesis of two novel Schiff's bases (cellulose-2,3-bis-[(4-methylene-amino)-benzene-sulfonamide] (5) & cellulose-2,3-bis-[(4-methylene-amino)-N-(thiazol-2-yl)-benzenesulfonamide] (6) via condensation reactions of periodate oxidized developed bacterial cellulose ODBC (2) with sulfa drugs [sulfanilamide (3) & sulfathiazole (4)] was reported. The physicochemical characterization of the condensation products was performed using FTIR, (1)H NMR, (13)C NMR spectral analyses, X-ray diffraction and DTA. The ODBC exhibited the highest degree of oxidation based on the aldehyde group number percentage (82.9%), which confirms the highest reactivity of developed bacterial cellulose [DBC (1)]. The X-ray diffractograms indicated an increase in the interplanar distance of the cellulose Schiff base (6) compared to ODBC (2) due to sulfathiazole (4) inclusion between ODBC (2) sheets corresponding to the 1 1 0 plane. In addition, the aldehyde content of Schiff base (6) was (20.8%) much lower than that of Schiff base (5) (41.5%). These results confirmed the high affinity of sulfathiazole (4) to the ODBC (2) chain, and the substantial changes in the original properties of ODBC were due to these chemical modifications rather than the sulfanilamide (3). Copyright © 2015 Elsevier Ltd. All rights reserved.

Synthesis and molecular structure of a zinc complex of the vitamin K3 analogue phthiocol

NASA Astrophysics Data System (ADS)

Kathawate, Laxmi; Sproules, Stephen; Pawar, Omkar; Markad, Ganesh; Haram, Santosh; Puranik, Vedavati; Salunke-Gawali, Sunita

2013-09-01

The complex [Zn(phthiocol)2(H2O)2]; 1, where phthiocol is 2-hydroxy-3-methyl-1,4-naphthoquinone, has been synthesized and characterized by elemental analysis, FT-IR, 1H NMR, UV-vis spectroscopy, thermogravimetric (TG) analysis, electrochemical and single crystal X-ray diffraction studies. The νCO stretch shifts to lower frequencies upon complexation of phthiocol to Zn2+. 1H NMR spectra show an upfield shift of the benzenoid ring protons in 1. There is a bathochromic shift of the LMCT band in the UV-vis spectra of 1. Single crystal X-ray structure of 1 show distorted octahedral geometry around Zn2+. Two phthiocol ligands are in plane with the metal, while water molecules are trans to this plane. Coordination of deprotonated phthiocol ligands is 'trans, trans' to Zn2+. Intra as well as intermolecular interactions are observed in 1. Molecules of 1 show three dimensional network through CH⋯O and OH⋯O interactions. Additional anodic peaks are observed in cyclic voltammogram of phthiocol ligand due to oxidation of reduced species formed during reduction. One-electron reduction of 1 is shown to be reversible and DFT studies define this redox event as ligand-centered.

X-ray topography using the forward transmitted beam under multiple-beam diffraction conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsusaka, Y., E-mail: tsusaka@sci.u-hyogo.ac.jp; Takano, H.; Takeda, S.

2016-02-15

X-ray topographs are taken for a sapphire wafer with the [0001] surface normal, as an example, by forward transmitted synchrotron x-ray beams combined with two-dimensional electronic arrays in the x-ray detector having a spatial resolution of 1 μm. They exhibit no shape deformation and no position shift of the dislocation lines on the topographs. Since the topography is performed under multiple-beam diffraction conditions, the topographic images of a single diffraction (two-wave approximation condition) or plural diffractions (six-wave approximation condition) can be recorded without large specimen position changes. As usual Lang topographs, it is possible to determine the Burgers vector ofmore » each dislocation line. Because of high parallelism of the incoming x-rays and linear sensitivity of the electronic arrays to the incident x-rays, the present technique can be used to visualize individual dislocations in single crystals of the dislocation density as high as 1 × 10{sup 5} cm{sup −2}.« less

Multiple defocused coherent diffraction imaging: method for simultaneously reconstructing objects and probe using X-ray free-electron lasers.

PubMed

Hirose, Makoto; Shimomura, Kei; Suzuki, Akihiro; Burdet, Nicolas; Takahashi, Yukio

2016-05-30

The sample size must be less than the diffraction-limited focal spot size of the incident beam in single-shot coherent X-ray diffraction imaging (CXDI) based on a diffract-before-destruction scheme using X-ray free electron lasers (XFELs). This is currently a major limitation preventing its wider applications. We here propose multiple defocused CXDI, in which isolated objects are sequentially illuminated with a divergent beam larger than the objects and the coherent diffraction pattern of each object is recorded. This method can simultaneously reconstruct both objects and a probe from the coherent X-ray diffraction patterns without any a priori knowledge. We performed a computer simulation of the prposed method and then successfully demonstrated it in a proof-of-principle experiment at SPring-8. The prposed method allows us to not only observe broad samples but also characterize focused XFEL beams.

Angular rheology study of colloidal nanocrystals using Coherent X-ray Diffraction

NASA Astrophysics Data System (ADS)

Liang, Mengning; Harder, Ross; Robinson, Ian

2007-03-01

A new method using coherent x-ray diffraction provides a way to investigate the rotational motion of a colloidal suspension of crystals in real time. Coherent x-ray diffraction uses the long coherence lengths of synchrotron sources to illuminate a nanoscale particle coherently over its spatial dimensions. The penetration of high energy x-rays into various media allows for in-situ measurements making it ideal for suspensions. This technique has been used to image the structure of nanocrystals for some time but also has the capability of providing information about the orientation and dynamics of crystals. The particles are imaged in a specific diffraction condition allowing us to determine their orientation and observe how they rotate in real time with exceptional resolution. Such sensitivity allows for the study of rotational Brownian motion of nanocrystals in various suspensions and conditions. We present a study of the angular rheology of alumina and TiO2 colloidal nanocrystals in media using coherent x-ray diffraction.

Characterization of polycrystalline materials using synchrotron X-ray imaging and diffraction techniques

NASA Astrophysics Data System (ADS)

Ludwig, W.; King, A.; Herbig, M.; Reischig, P.; Marrow, J.; Babout, L.; Lauridsen, E. M.; Proudhon, H.; Buffière, J. Y.

2010-12-01

The combination of synchrotron radiation x-ray imaging and diffraction techniques offers new possibilities for in-situ observation of deformation and damage mechanisms in the bulk of polycrystalline materials. Minute changes in electron density (i.e., cracks, porosities) can be detected using propagation based phase contrast imaging, a 3-D imaging mode exploiting the coherence properties of third generation synchrotron beams. Furthermore, for some classes of polycrystalline materials, one may use a 3-D variant of x-ray diffraction imaging, termed x-ray diffraction contrast tomography. X-ray diffraction contrast tomography provides access to the 3-D shape, orientation, and elastic strain state of the individual grains from polycrystalline sample volumes containing up to thousand grains. Combining both imaging modalities, one obtains a comprehensive description of the materials microstructure at the micrometer length scale. Repeated observation during (interrupted) mechanical tests provide unprecedented insight into crystallographic and grain microstructure related aspects of polycrystalline deformation and degradation mechanisms.

Quantitative analysis of thoria phase in Th-U alloys using diffraction studies

NASA Astrophysics Data System (ADS)

Thakur, Shital; Krishna, P. S. R.; Shinde, A. B.; Kumar, Raj; Roy, S. B.

2017-05-01

In the present study the quantitative phase analysis of Th-U alloys in bulk form namely Th-52 wt% U and Th-3wt%U has been performed over the data obtained from both X ray diffraction and neutron diffraction technique using Rietveld method of FULLPROF software. Quantifying thoria (ThO2) phase present in bulk of the sample is limited due to surface oxidation and low penetration of x rays in high Z material. Neutron diffraction study probing bulk of the samples has been presented in comparison with x-ray diffraction study.

Selenium single-wavelength anomalous diffraction de novo phasing using an X-ray-free electron laser

DOE PAGES

Hunter, Mark S.; Yoon, Chun Hong; DeMirci, Hasan; ...

2016-11-04

Structural information about biological macromolecules near the atomic scale provides important insight into the functions of these molecules. To date, X-ray crystallography has been the predominant method used for macromolecular structure determination. However, challenges exist when solving structures with X-rays, including the phase problem and radiation damage. X-ray-free electron lasers (X-ray FELs) have enabled collection of diffraction information before the onset of radiation damage, yet the majority of structures solved at X-ray FELs have been phased using external information via molecular replacement. De novo phasing at X-ray FELs has proven challenging due in part to per-pulse variations in intensity andmore » wavelength. Here we report the solution of a selenobiotinyl-streptavidin structure using phases obtained by the anomalous diffraction of selenium measured at a single wavelength (Se-SAD) at the Linac Coherent Light Source. Finally, our results demonstrate Se-SAD, routinely employed at synchrotrons for novel structure determination, is now possible at X-ray FELs.« less

Macromolecular structures probed by combining single-shot free-electron laser diffraction with synchrotron coherent X-ray imaging.

PubMed

Gallagher-Jones, Marcus; Bessho, Yoshitaka; Kim, Sunam; Park, Jaehyun; Kim, Sangsoo; Nam, Daewoong; Kim, Chan; Kim, Yoonhee; Noh, Do Young; Miyashita, Osamu; Tama, Florence; Joti, Yasumasa; Kameshima, Takashi; Hatsui, Takaki; Tono, Kensuke; Kohmura, Yoshiki; Yabashi, Makina; Hasnain, S Samar; Ishikawa, Tetsuya; Song, Changyong

2014-05-02

Nanostructures formed from biological macromolecular complexes utilizing the self-assembly properties of smaller building blocks such as DNA and RNA hold promise for many applications, including sensing and drug delivery. New tools are required for their structural characterization. Intense, femtosecond X-ray pulses from X-ray free-electron lasers enable single-shot imaging allowing for instantaneous views of nanostructures at ambient temperatures. When combined judiciously with synchrotron X-rays of a complimentary nature, suitable for observing steady-state features, it is possible to perform ab initio structural investigation. Here we demonstrate a successful combination of femtosecond X-ray single-shot diffraction with an X-ray free-electron laser and coherent diffraction imaging with synchrotron X-rays to provide an insight into the nanostructure formation of a biological macromolecular complex: RNA interference microsponges. This newly introduced multimodal analysis with coherent X-rays can be applied to unveil nano-scale structural motifs from functional nanomaterials or biological nanocomplexes, without requiring a priori knowledge.

Combined analysis of 1,3-benzodioxoles by crystalline sponge X-ray crystallography and laser desorption ionization mass spectrometry.

PubMed

Hayashi, Yukako; Ohara, Kazuaki; Taki, Rika; Saeki, Tomomi; Yamaguchi, Kentaro

2018-03-12

The crystalline sponge (CS) method, which employs single-crystal X-ray diffraction to determine the structure of an analyte present as a liquid or an oil and having a low melting point, was used in combination with laser desorption ionization mass spectrometry (LDI-MS). 1,3-Benzodioxole derivatives were encapsulated in CS and their structures were determined by combining X-ray crystallography and MS. After the X-ray analysis, the CS was subjected to imaging mass spectrometry (IMS) with an LDI spiral-time-of-flight mass spectrometer (TOF-MS). The ion detection area matched the microscopic image of the encapsulated CS. In addition, the accumulated 1D mass spectra showed that fragmentation of the guest molecule (hereafter, guest) can be easily visualized without any interference from the fragment ions of CS except for two strong ion peaks derived from the tridentate ligand TPT (2,4,6-tris(4-pyridyl)-1,3,5-triazine) of the CS and its fragment. X-ray analysis clearly showed the presence of the guest as well as the π-π, CH-halogen, and CH-O interactions between the guest and the CS framework. However, some guests remained randomly diffused in the nanopores of CS. In addition, the detection limit was less than sub-pmol order based on the weight and density of CS determined by X-ray analysis. Spectroscopic data, such as UV-vis and NMR, also supported the encapsulation of the guest through the interaction between the guest and CS components. The results denote that the CS-LDI-MS method, which combines CS, X-ray analysis and LDI-MS, is effective for structure determination.

Exploration of New Principles in Spintronics Based on Topological Insulators (Option 1)

DTIC Science & Technology

2012-05-14

on the surface and found that our crystals are exceedingly homogeneous (Supplementary Information). The persistently narrow X - ray diffraction peaks...modified Bridgman method (see Supplementary Information for details). X - ray diffraction measurements indicated the monotonic shrinkage of a and c axis...and annealing at that temperature for 4 days. X - ray diffraction analyses confirmed that all the samples have the same crystal structure (R 3m

Efficient modeling of Bragg coherent x-ray nanobeam diffraction

DOE PAGES

Hruszkewycz, S. O.; Holt, M. V.; Allain, M.; ...

2015-07-02

X-ray Bragg diffraction experiments that utilize tightly focused coherent beams produce complicated Bragg diffraction patterns that depend on scattering geometry, characteristics of the sample, and properties of the x-ray focusing optic. In this paper, we use a Fourier-transform-based method of modeling the 2D intensity distribution of a Bragg peak and apply it to the case of thin films illuminated with a Fresnel zone plate in three different Bragg scattering geometries. Finally, the calculations agree well with experimental coherent diffraction patterns, demonstrating that nanodiffraction patterns can be modeled at nonsymmetric Bragg conditions with this approach—a capability critical for advancing nanofocused x-raymore » diffraction microscopy.« less

HiSPoD: a program for high-speed polychromatic X-ray diffraction experiments and data analysis on polycrystalline samples

DOE PAGES

Sun, Tao; Fezzaa, Kamel

2016-06-17

Here, a high-speed X-ray diffraction technique was recently developed at the 32-ID-B beamline of the Advanced Photon Source for studying highly dynamic, yet non-repeatable and irreversible, materials processes. In experiments, the microstructure evolution in a single material event is probed by recording a series of diffraction patterns with extremely short exposure time and high frame rate. Owing to the limited flux in a short pulse and the polychromatic nature of the incident X-rays, analysis of the diffraction data is challenging. Here, HiSPoD, a stand-alone Matlab-based software for analyzing the polychromatic X-ray diffraction data from polycrystalline samples, is described. With HiSPoD,more » researchers are able to perform diffraction peak indexing, extraction of one-dimensional intensity profiles by integrating a two-dimensional diffraction pattern, and, more importantly, quantitative numerical simulations to obtain precise sample structure information.« less

X-ray diffraction and X-ray standing-wave study of the lead stearate film structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blagov, A. E.; Dyakova, Yu. A.; Kovalchuk, M. V.

2016-05-15

A new approach to the study of the structural quality of crystals is proposed. It is based on the use of X-ray standing-wave method without measuring secondary processes and considers the multiwave interaction of diffraction reflections corresponding to different harmonics of the same crystallographic reflection. A theory of multiwave X-ray diffraction is developed to calculate the rocking curves in the X-ray diffraction scheme under consideration for a long-period quasi-one-dimensional crystal. This phase-sensitive method is used to study the structure of a multilayer lead stearate film on a silicon substrate. Some specific structural features are revealed for the surface layer ofmore » the thin film, which are most likely due to the tilt of the upper layer molecules with respect to the external normal to the film surface.« less

Molybdenum cell for x-ray diffraction measurements of fluid alkali metals at high temperatures and high pressures

NASA Astrophysics Data System (ADS)

Matsuda, Kazuhiro; Tamura, Kozaburo; Katoh, Masahiro; Inui, Masanori

2004-03-01

We have developed a sample cell for x-ray diffraction measurements of fluid alkali metals at high temperatures and high pressures. All parts of the cell are made of molybdenum which is resistant to the chemical corrosion of alkali metals. Single crystalline molybdenum disks electrolytically thinned down to 40 μm were used as the walls of the cell through which x rays pass. The crystal orientation of the disks was controlled in order to reduce the background from the cell. All parts of the cell were assembled and brazed together using a high-temperature Ru-Mo alloy. Energy dispersive x-ray diffraction measurements have been successfully carried out for fluid rubidium up to 1973 K and 16.2 MPa. The obtained S(Q) demonstrates the applicability of the molybdenum cell to x-ray diffraction measurements of fluid alkali metals at high temperatures and high pressures.

High-resolution ab initio three-dimensional x-ray diffraction microscopy

DOE PAGES

Chapman, Henry N.; Barty, Anton; Marchesini, Stefano; ...

2006-01-01

Coherent x-ray diffraction microscopy is a method of imaging nonperiodic isolated objects at resolutions limited, in principle, by only the wavelength and largest scattering angles recorded. We demonstrate x-ray diffraction imaging with high resolution in all three dimensions, as determined by a quantitative analysis of the reconstructed volume images. These images are retrieved from the three-dimensional diffraction data using no a priori knowledge about the shape or composition of the object, which has never before been demonstrated on a nonperiodic object. We also construct two-dimensional images of thick objects with greatly increased depth of focus (without loss of transverse spatialmore » resolution). These methods can be used to image biological and materials science samples at high resolution with x-ray undulator radiation and establishes the techniques to be used in atomic-resolution ultrafast imaging at x-ray free-electron laser sources.« less

Enhancing resolution in coherent x-ray diffraction imaging.

PubMed

Noh, Do Young; Kim, Chan; Kim, Yoonhee; Song, Changyong

2016-12-14

Achieving a resolution near 1 nm is a critical issue in coherent x-ray diffraction imaging (CDI) for applications in materials and biology. Albeit with various advantages of CDI based on synchrotrons and newly developed x-ray free electron lasers, its applications would be limited without improving resolution well below 10 nm. Here, we review the issues and efforts in improving CDI resolution including various methods for resolution determination. Enhancing diffraction signal at large diffraction angles, with the aid of interference between neighboring strong scatterers or templates, is reviewed and discussed in terms of increasing signal-to-noise ratio. In addition, we discuss errors in image reconstruction algorithms-caused by the discreteness of the Fourier transformations involved-which degrade the spatial resolution, and suggest ways to correct them. We expect this review to be useful for applications of CDI in imaging weakly scattering soft matters using coherent x-ray sources including x-ray free electron lasers.

A portable X-ray diffraction apparatus for in situ analyses of masters' paintings

NASA Astrophysics Data System (ADS)

Eveno, Myriam; Duran, Adrian; Castaing, Jacques

2010-09-01

It is rare that the analyses of materials in paintings can be carried out by taking micro-samples. Valuable works of art are best studied in situ by non-invasive techniques. For that purpose, a portable X-ray diffraction and fluorescence apparatus has been designed and constructed at the C2RMF. This apparatus has been used for paintings of Rembrandt, Leonardo da Vinci, Van Gogh, Mantegna, etc. Results are given to illustrate the performance of X-ray diffraction, especially when X-ray fluorescence does not bring sufficient information to conclude.

Synthesis, crystal structure and investigation of mononuclear copper(II) and zinc(II) complexes of a new carboxylate rich tripodal ligand and their interaction with carbohydrates in alkaline aqueous solution

PubMed Central

Stewart, Christopher D.; Pedraza, Mayra; Arman, Hadi; Fan, Hua-Jun; Schilling, Eduardo Luiz; Szpoganicz, Bruno; Musie, Ghezai T.

2016-01-01

A new carboxylate rich asymmetric tripodal ligand, N-[2-carboxybenzomethyl]-N-[carboxymethyl]-β-alanine (H3camb), and its di-copper(II), (NH4)2[1]2, and di-zinc(II), ((CH3)4 N)2[2]2, complexes have been synthesized as carbohydrate binding models in aqueous solutions. The ligand and complexes have been fully characterized using several techniques, including single crystal X-ray diffraction. The interactions of (NH4)2[1]2 and ((CH3)4 N)2[2]2 with D-glucose, D-mannose, D-xylose and xylitol in aqueous alkaline media were investigated using UV–Vis and 13C-NMR spectroscopic techniques, respectively. The molar conductance, NMR and ESI–MS studies indicate that the complexes dissociate in solution to produce the respective complex anions, 1− and 2−. Complexes 1− and 2− showed chelating ability towards the naturally abundant and biologically relevant sugars, D-glucose, D-mannose, D-xylose, and xylitol. The complex ions bind to one molar equivalent of the sugars, even in the presence of stoichiometric excess of the substrates, in solution. Experimentally obtained spectroscopic data and computational results suggest that the substrates bind to the metal center in a bidentate fashion. Apparent binding constant values, pKapp, between the complexes and the substrates were determined and a specific mode of substrate binding is proposed. The pKapp and relativistic density functional theory (DFT) calculated Gibbs free energy values indicate that D-mannose displayed the strongest interaction with the complexes. Syntheses, characterizations, detailed substrate binding studies using spectroscopic techniques, single crystal X-ray diffraction and geometry optimizations of the complex-substrates with DFT calculations are also reported. PMID:25969174

Structural Properties, Order–Disorder Phenomena, and Phase Stability of Orotic Acid Crystal Forms

PubMed Central

2016-01-01

Orotic acid (OTA) is reported to exist in the anhydrous (AH), monohydrate (Hy1), and dimethyl sulfoxide monosolvate (SDMSO) forms. In this study we investigate the (de)hydration/desolvation behavior, aiming at an understanding of the elusive structural features of anhydrous OTA by a combination of experimental and computational techniques, namely, thermal analytical methods, gravimetric moisture (de)sorption studies, water activity measurements, X-ray powder diffraction, spectroscopy (vibrational, solid-state NMR), crystal energy landscape, and chemical shift calculations. The Hy1 is a highly stable hydrate, which dissociates above 135 °C and loses only a small part of the water when stored over desiccants (25 °C) for more than one year. In Hy1, orotic acid and water molecules are linked by strong hydrogen bonds in nearly perfectly planar arranged stacked layers. The layers are spaced by 3.1 Å and not linked via hydrogen bonds. Upon dehydration the X-ray powder diffraction and solid-state NMR peaks become broader, indicating some disorder in the anhydrous form. The Hy1 stacking reflection (122) is maintained, suggesting that the OTA molecules are still arranged in stacked layers in the dehydration product. Desolvation of SDMSO, a nonlayer structure, results in the same AH phase as observed upon dehydrating Hy1. Depending on the desolvation conditions, different levels of order–disorder of layers present in anhydrous OTA are observed, which is also suggested by the computed low energy crystal structures. These structures provide models for stacking faults as intergrowth of different layers is possible. The variability in anhydrate crystals is of practical concern as it affects the moisture dependent stability of AH with respect to hydration. PMID:26741914

Evidence for Novel β-Sheet Structures in Iowa Mutant β-Amyloid Fibrils†

PubMed Central

Tycko, Robert; Sciarretta, Kimberly L.; Orgel, Joseph P. R. O.; Meredith, Stephen C.

2009-01-01

Asp23-to-Asn mutation within the coding sequence of β-amyloid, called the Iowa mutation, is associated with early onset, familial Alzheimer’s disease and cerebral amyloid angiopathy, in which patients develop neuritic plaques and massive vascular deposition predominantly of the mutant peptide. We examined the mutant peptide, D23N-Aβ40, by electron microscopy, X-ray diffraction, and solid-state NMR spectroscopy. D23N-Aβ40 forms fibrils considerably faster than the wild-type peptide (k = 3.77 × 10-3 min-1 and 1.07 × 10-4 min-1 for D23N-Aβ40 and the wild-type peptide WT-Aβ40, respectively) and without a lag phase. Electron microscopy shows that D23N-Aβ40 forms fibrils with multiple morphologies. X-ray fiber diffraction shows a cross-β pattern, with a sharp reflection at 4.7 Å and a broad reflection at 9.4 Å, which is notably smaller than the value for WT-Aβ40 fibrils (10.4 Å). Solid-state NMR measurements indicate molecular level polymorphism of the fibrils, with only a minority of D23N-Aβ40 fibrils containing the in-register, parallel β-sheet structure commonly found in WT-Aβ40 fibrils and most other amyloid fibrils. Antiparallel β-sheet structures in the majority of fibrils are indicated by measurements of intermolecular distances through 13C-13C and 15N-13C dipole-dipole couplings. An intriguing possibility exists that there is a relationship between the aberrant structure of D23N-Aβ40 fibrils and the unusual vasculotropic clinical picture in these patients. PMID:19358576

X-ray fractography on fatigue fractured surface of austenitic stainless steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yajima, Zenjiro; Tokuyama, Hideki; Kibayashi, Yasuo

1995-12-31

X-ray diffraction observation of the material internal structure beneath fracture surfaces provide fracture analysis with useful information to investigate the conditions and mechanisms of fracture. X-ray fractography is a generic name given to this technique. In the present study, X-ray fractography was applied to fatigue fracture surfaces of austenitic stainless steel (AISI 304) which consisted of solution treatment. The fatigue tests were carried out on compact tension (CT) specimens. The plastic strain on the fracture surface was estimated from measuring the line broadening of X-ray diffraction profiles. The line broadening of X-ray diffraction profiles was measured on and beneath fatiguemore » fracture surfaces. The depth of the plastic zone left on fracture surfaces was evaluated from the line broadening. The results are discussed on the basis of fracture mechanics.« less

Toward in situ x-ray diffraction imaging at the nanometer scale

NASA Astrophysics Data System (ADS)

Zatsepin, Nadia A.; Dilanian, Ruben A.; Nikulin, Andrei Y.; Gable, Brian M.; Muddle, Barry C.; Sakata, Osami

2008-08-01

We present the results of preliminary investigations determining the sensitivity and applicability of a novel x-ray diffraction based nanoscale imaging technique, including simulations and experiments. The ultimate aim of this nascent technique is non-destructive, bulk-material characterization on the nanometer scale, involving three dimensional image reconstructions of embedded nanoparticles and in situ sample characterization. The approach is insensitive to x-ray coherence, making it applicable to synchrotron and laboratory hard x-ray sources, opening the possibility of unprecedented nanometer resolution with the latter. The technique is being developed with a focus on analyzing a technologically important light metal alloy, Al-xCu (where x is 2.0-5.0 %wt). The mono- and polycrystalline samples contain crystallographically oriented, weakly diffracting Al2Cu nanoprecipitates in a sparse, spatially random dispersion within the Al matrix. By employing a triple-axis diffractometer in the non-dispersive setup we collected two-dimensional reciprocal space maps of synchrotron x-rays diffracted from the Al2Cu nanoparticles. The intensity profiles of the diffraction peaks confirmed the sensitivity of the technique to the presence and orientation of the nanoparticles. This is a fundamental step towards in situ observation of such extremely sparse, weakly diffracting nanoprecipitates embedded in light metal alloys at early stages of their growth.

Diffraction and Imaging Study of Imperfections of Protein Crystals with Coherent X-rays

NASA Technical Reports Server (NTRS)

Hu, Z. W.; Thomas, B. R.; Chernov, A. A.; Chu, Y. S.; Lai, B.

2004-01-01

High angular-resolution x-ray diffraction and phase contrast x-ray imaging were combined to study defects and perfection of protein crystals. Imperfections including line defects, inclusions and other microdefects were observed in the diffraction images of a uniformly grown lysozyme crystal. The observed line defects carry distinct dislocation features running approximately along the <110> growth front and have been found to originate mostly in a central growth area and occasionally in outer growth regions. Slow dehydration led to the broadening of a fairly symmetric 4 4 0 rocking curve by a factor of approximately 2.6, which was primarily attributed to the dehydration-induced microscopic effects that are clearly shown in diffraction images. X-ray imaging and diffraction characterization of the quality of apoferritin crystals will also be discussed in the presentation.

THE EFFECT OF SATELLITE LINES FROM THE X-RAY SOURCE ON X-RAY DIFFRACTION PEAKS

EPA Science Inventory

The article discusses the development of a method for relating reactivity to crystallite size and strain parameters obtained by the Warren-Averbach technique. EPA has been using crystallite size and strain data obtained from x-ray diffraction (XRD) peak profile analysis to predic...

History and Solution of the Phase Problem in theTheory of Structure Determination of Crystals from X-ray Diffraction Experiments

ScienceCinema

Wolf, Emil [University of Rochester, Rochester, New York, United States

2017-12-09

Since the pioneering work of Max von Laue on interference and diffraction of x-rays, carried out almost 100 years ago, numerous attempts have been made to determine structures of crystalline media from x-ray diffraction experiments. The usefulness of all of them has been limited by the inability of measuring phases of the diffracted beams. In this talk, the most important research carried out in this field will be reviewed and a recently obtained solution of the phase problem will be presented.

XRayView: a teaching aid for X-ray crystallography.

PubMed

Phillips, G N

1995-10-01

A software package, XRayView, has been developed that uses interactive computer graphics to introduce basic concepts of x-ray diffraction by crystals, including the reciprocal lattice, the Ewald sphere construction, Laue cones, the wavelength dependence of the reciprocal lattice, primitive and centered lattices and systematic extinctions, rotation photography. Laue photography, space group determination and Laue group symmetry, and the alignment of crystals by examination of reciprocal space. XRayView is designed with "user-friendliness" in mind, using pull-down menus to control the program. Many of the experiences of using real x-ray diffraction equipment to examine crystalline diffraction can be simulated. Exercises are available on-line to guide the users through many typical x-ray diffraction experiments.

Application of MEMS-based x-ray optics as tuneable nanosecond choppers

NASA Astrophysics Data System (ADS)

Chen, Pice; Walko, Donald A.; Jung, Il Woong; Li, Zhilong; Gao, Ya; Shenoy, Gopal K.; Lopez, Daniel; Wang, Jin

2017-08-01

Time-resolved synchrotron x-ray measurements often rely on using a mechanical chopper to isolate a set of x-ray pulses. We have started the development of micro electromechanical systems (MEMS)-based x-ray optics, as an alternate method to manipulate x-ray beams. In the application of x-ray pulse isolation, we recently achieved a pulse-picking time window of half a nanosecond, which is more than 100 times faster than mechanical choppers can achieve. The MEMS device consists of a comb-drive silicon micromirror, designed for efficiently diffracting an x-ray beam during oscillation. The MEMS devices were operated in Bragg geometry and their oscillation was synchronized to x-ray pulses, with a frequency matching subharmonics of the cycling frequency of x-ray pulses. The microscale structure of the silicon mirror in terms of the curvature and the quality of crystallinity ensures a narrow angular spread of the Bragg reflection. With the discussion of factors determining the diffractive time window, this report showed our approaches to narrow down the time window to half a nanosecond. The short diffractive time window will allow us to select single x-ray pulse out of a train of pulses from synchrotron radiation facilities.

Fabrication of high-resolution x-ray diffractive optics at King's College London

NASA Astrophysics Data System (ADS)

Charalambous, Pambos S.; Anastasi, Peter A. F.; Burge, Ronald E.; Popova, Katia

1995-09-01

The fabrication of high resolution x-ray diffractive optics, and Fresnel zone plates (ZPs) in particular, is a very demanding multifaceted technological task. The commissioning of more (and brighter) synchrotron radiation sources, has increased the number of x-ray imaging beam lines world wide. The availability of cheaper and more effective laboratory x-ray sources, has further increased the number of laboratories involved in x-ray imaging. The result is an ever increasing demand for x-ray optics with a very wide range of specifications, reflecting the particular type of x-ray imaging performed at different laboratories. We have been involved in all aspects of high resolution nanofabrication for a number of years, and we have explored many different methods of lithography, which, although unorthodox, open up possibilities, and increase our flexibility for the fabrication of different diffractive optical elements, as well as other types of nanostructures. The availability of brighter x-ray sources, means that the diffraction efficiency of the ZPs is becoming of secondary importance, a trend which will continue in the future. Resolution, however, is important and will always remain so. Resolution is directly related to the accuracy af pattern generation, as well as the ability to draw fine lines. This is the area towards which we have directed most of our efforts so far.

Synthesis and characterization of silver nanoparticles from (bis)alkylamine silver carboxylate precursors.

PubMed

Uznanski, Pawel; Zakrzewska, Joanna; Favier, Frederic; Kazmierski, Slawomir; Bryszewska, Ewa

2017-01-01

A comparative study of amine and silver carboxylate adducts [R 1 COOAg-2(R 2 NH 2 )] (R 1  = 1, 7, 11; R 2  = 8, 12) as a key intermediate in NPs synthesis is carried out via differential scanning calorimetry, solid-state FT-infrared spectroscopy, 13 C CP MAS NMR, powder X-ray diffraction and X-ray photoelectron spectroscopy, and various solution NMR spectroscopies ( 1 H and 13 C NMR, pulsed field gradient spin-echo NMR, and ROESY). It is proposed that carboxyl moieties in the presence of amine ligands are bound to silver ions via chelating bidentate type of coordination as opposed to bridging bidentate coordination of pure silver carboxylates resulting from the formation of dimeric units. All complexes are packed as lamellar bilayer structures. Silver carboxylate/amine complexes show one first-order melting transition. The evidence presented in this study shows that phase behavior of monovalent metal carboxylates are controlled, mainly, by head group bonding. In solution, insoluble silver salt is stabilized by amine molecules which exist in dynamic equilibrium. Using (bis)amine-silver carboxylate complex as precursor, silver nanoparticles were fabricated. During high-temperature thermolysis, the (bis)amine-carboxylate adduct decomposes to produce silver nanoparticles of small size. NPs are stabilized by strongly interacting carboxylate and trace amounts of amine derived from the silver precursor interacting with carboxylic acid. A corresponding aliphatic amide obtained from silver precursor at high-temperature reaction conditions is not taking part in the stabilization. Combining NMR techniques with FTIR, it was possible to follow an original stabilization mechanism. Graphical abstractThe synthesis of a series (bis)alkylamine silver(I) carboxylate complexes in nonpolar solvents were carried out and fully characterized both in the solid and solution. Carboxyl moieties in the presence of amine ligands are bound to silver ions via chelating bidentate type of coordination. The complexes form layered structures which thermally decompose forming nanoparticles stabilized only by aliphatic carboxylates.

N-Sulfinylimine compounds, R-NSO: a chemistry family with strong temperament

NASA Astrophysics Data System (ADS)

Romano, R. M.; Della Védova, C. O.

2000-04-01

In this review, an update on the structural properties and theoretical studies of N-sulfinylimine compounds (R-NSO) is reported. They were deduced using several experimental techniques: gas-electron diffraction (GED), X-ray diffraction, 17O NMR, ultraviolet-visible absorption spectroscopy (UV-Vis), FTIR (including matrix studies of molecular randomisation) and Raman (including pre-resonant Raman spectra). Data are compared with those obtained by theoretical calculations. With these tools, excited state geometry using the time-dependent theory was calculated for these kinds of compounds. The existence of pre-resonant Raman effect was reported recently for R-NSO compounds. The configuration of R-NSO compounds was checked for this series confirming the existence of only one syn configuration. This finding is corroborated by theoretical calculations. The method of preparation is also summarised.

Teaching wave phenomena via biophysical applications

NASA Astrophysics Data System (ADS)

Reich, Daniel; Robbins, Mark; Leheny, Robert; Wonnell, Steven

2014-03-01

Over the past several years we have developed a two-semester second-year physics course sequence for students in the biosciences, tailored in part to the needs of undergraduate biophysics majors. One semester, ``Biological Physics,'' is based on the book of that name by P. Nelson. This talk will focus largely on the other semester, ``Wave Phenomena with Biophysical Applications,'' where we provide a novel introduction to the physics of waves, primarily through the study of experimental probes used in the biosciences that depend on the interaction of electromagnetic radiation with matter. Topic covered include: Fourier analysis, sound and hearing, diffraction - culminating in an analysis of x-ray fiber diffraction and its use in the determination of the structure of DNA - geometrical and physical optics, the physics of modern light microscopy, NMR and MRI. Laboratory exercises tailored to this course will also be described.

Zintl Clusters as Wet-Chemical Precursors for Germanium Nanomorphologies with Tunable Composition.

PubMed

Bentlohner, Manuel M; Waibel, Markus; Zeller, Patrick; Sarkar, Kuhu; Müller-Buschbaum, Peter; Fattakhova-Rohlfing, Dina; Fässler, Thomas F

2016-02-12

[Ge9](4-) Zintl clusters are used as soluble germanium source for a bottom-up fabrication of Ge nanomorphologies such as inverse opal structures with tunable composition. The method is based on the assembly and oxidation of [Ge9 ](4-) clusters in a template mold using SiCl4 , GeCl4 , and PCl3 leading to Si and P-containing Ge phases as shown by X-ray diffraction, Raman spectroscopy, and energy-dispersive X-ray analysis. [Ge9](4-) clusters are retained using ethylenediamine (en) as a transfer medium to a mold after removal of the solvent if water is thoroughly excluded, but are oxidized to amorphous Ge in presence of water traces. (1)H NMR spectroscopy reveals the oxidative deprotonation of en by [Ge9](4-). Subsequent annealing leads to crystalline Ge. As an example for wet-chemical synthesis of complex Ge nanomorphologies, we describe the fabrication of undoped and P-doped inverse opal-structured Ge films with a rather low oxygen contents. The morphology of the films with regular volume porosity is characterized by SEM, TEM, and grazing incidence small-angle X-ray scattering. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sonication-assisted synthesis of a new cationic zinc nitrate complex with a tetradentate Schiff base ligand: Crystal structure, Hirshfeld surface analysis and investigation of different parameters influence on morphological properties.

PubMed

Mousavi, S A; Montazerozohori, M; Masoudiasl, A; Mahmoudi, G; White, J M

2018-09-01

A nanostructured cationic zinc nitrate complex with a formula of [ZnLNO 3 ]NO 3 (where L = (N 2 E,N 2' E)-N 1 ,N 1' -(ethane-1,2-diyl)bis(N 2 -((E)-3-phenylallylidene)ethane-1,2-diamine)) was prepared by sonochemical process and characterized by single crystal X-ray crystallography, scanning electron microscopy (SEM), FT-IR and NMR spectroscopy and X-ray powder diffraction (XRPD). The X-ray analysis demonstrates the formation of a cationic complex that metal center is five-coordinated by four nitrogen atom from Schiff base ligand and one oxygen atom from nitrate group. The crystal packing analysis demonstrates the essential role of the nitrate groups in the organization of supramolecular structure. The morphology and size of ultrasound-assisted synthesized zinc nitrate complex have been investigated using scanning electron microscopy (SEM) by changing parameters such as the concentration of initial reactants, the sonication power and reaction temperature. In addition the calcination of zinc nitrate complex in air atmosphere led to production of zinc oxide nanoparticles. Copyright © 2018. Published by Elsevier B.V.

Two-photon x-ray diffraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stohr, J.

The interference pattern of a circular photon source has long been used to define the optical diffraction limit. Here we show the breakdown of conventional x-ray diffraction theory for the fundamental case of a “source”, consisting of a back-illuminated thin film in a circular aperture. When the conventional spontaneous x-ray scattering by atoms in the film is replaced at high incident intensity by stimulated resonant scattering, the film becomes the source of cloned photon twins and the diffraction pattern becomes self-focused beyond the diffraction limit. Furthermore, the case of cloned photon pairs is compared to and distinguished from entangled photonmore » pairs or biphotons.« less

Two-photon x-ray diffraction

DOE PAGES

Stohr, J.

2017-01-11

The interference pattern of a circular photon source has long been used to define the optical diffraction limit. Here we show the breakdown of conventional x-ray diffraction theory for the fundamental case of a “source”, consisting of a back-illuminated thin film in a circular aperture. When the conventional spontaneous x-ray scattering by atoms in the film is replaced at high incident intensity by stimulated resonant scattering, the film becomes the source of cloned photon twins and the diffraction pattern becomes self-focused beyond the diffraction limit. Furthermore, the case of cloned photon pairs is compared to and distinguished from entangled photonmore » pairs or biphotons.« less

Intricate Short-Range Ordering and Strongly Anisotropic Transport Properties of Li 1–x Sn 2+x As 2

DOE PAGES

Lee, Kathleen; Kaseman, Derrick; Sen, Sabyasachi; ...

2015-02-22

A new ternary compound, Li 1-xSn 2+xAs 2, 0.2 < x < 0.4, was synthesized via solid-state reaction of elements. The compound crystallizes in a layered structure in the Rmore » $$\\overline{3}m$$ space group (No. 166) with Sn-As layers separated by layers of jointly occupied Li/Sn. The Sn-As layers are comprised of Sn 3As 3 puckered hexagons in a chair conformation that share all edges. Li/Sn atoms in the interlayer space are surrounded by a regular As 6 octahedron. Thorough investigations by synchrotron x-ray and neutron powder diffraction indicate no long-range Li/Sn ordering. In contrast, local Sn/Li ordering was revealed by synergistic investigations via solid-state 6,7Li NMR spectroscopy, HR-TEM, and neutron and X-ray pair distribution function analyses. Due to their different chemical natures, Li and Sn atoms tend to segregate into Li-rich and Sn-rich regions creating substantial inhomogeneity on the nanoscale. Inhomogeneous local structure has high impact on the physical properties of the synthesized compounds: local Li/Sn ordering and multiple nanoscale interfaces result in unexpectedly low thermal conductivity and highly anisotropic resistivity in Li 1-xSn 2+xAs 2.« less

Characterization of X80 and X100 Microalloyed Pipeline Steel Using Quantitative X-ray Diffraction

NASA Astrophysics Data System (ADS)

Wiskel, J. B.; Li, X.; Ivey, D. G.; Henein, H.

2018-06-01

Quantitative X-ray diffraction characterization of four (4) X80 and three (3) X100 microalloyed steels was undertaken. The effect of through-thickness position, processing parameters, and composition on the measured crystallite size, microstrain, and J index (relative magnitude of crystallographic texture) was determined. Microstructure analysis using optical microscopy, scanning electron microscopy, transmission electron microscopy, and electron-backscattered diffraction was also undertaken. The measured value of microstrain increased with increasing alloy content and decreasing cooling interrupt temperature. Microstructural features corresponding to crystallite size in the X80 steels were both above and below the detection limit for quantitative X-ray diffraction. The X100 steels consistently exhibited microstructure features below the crystallite size detection limit. The yield stress of each steel increased with increasing microstrain. The increase in microstrain from X80 to X100 is also associated with a change in microstructure from predominantly polygonal ferrite to bainitic ferrite.

Esterification of phenyl acetic acid with p-cresol using metal cation exchanged montmorillonite nanoclay catalysts.

PubMed

Bhaskar, M; Surekha, M; Suma, N

2018-02-01

The liquid phase esterification of phenyl acetic acid with p -cresol over different metal cation exchanged montmorillonite nanoclays yields p -cresyl phenyl acetate. Different metal cation exchanged montmorillonite nanoclays (M n +  = Al 3+ , Zn 2+ , Mn 2+ , Fe 3+ , Cu 2+ ) were prepared and the catalytic activity was studied. The esterification reaction was conducted by varying molar ratio of the reactants, reaction time and catalyst amount on the yield of the ester. Among the different metal cation exchanged catalysts used, Al 3+ -montmorillonite nanoclay was found to be more active. The characterization of the material used was studied under different techniques, namely X-ray diffraction, scanning electron microscopy and thermogravimetric analysis. The product obtained, p -cresyl phenyl acetate, was identified by thin-layer chromotography and confirmed by Fourier transform infrared, 1 H NMR and 13 C NMR. The regeneration activity of used catalyst was also investigated up to fourth generation.

Self-assembling of dihydroxypropyl 5,6-dihydrothymine derivatives

NASA Astrophysics Data System (ADS)

Cetina, Mario; Makarević, Janja; Nura-Lama, Afërdita

2010-09-01

( R, S)-1-(2',3'-Dibenzoyloxypropyl)-5,6-dihydrothymine ( 2) was synthesized from ( R, S)-1-(2',3'-dihydroxypropyl)-5,6-dihydrothymine and its structure has been analyzed by X-ray diffraction, NMR and FTIR spectroscopic methods. The molecular structure and supramolecular assembling of 2 is compared with the structure of its dimesyloxypropyl analogue ( 1). Compound 1 crystallizes as cocrystal of two diastereoisomers, while 2 crystallizes as a racemic mixture. Main hydrogen-bonded motif in both compounds is dimer formed by pair of N sbnd H···O( dbnd C) hydrogen bonds, which are further linked by C sbnd H···O hydrogen bonds. Phenyl rings of dibenzoyl-dihydropyrimidine moieties of 2 participate also in supramolecular aggregation via three C sbnd H···π interactions. Hydrogen bonding as driving force of 2 self-assembly was proving by the NMR and FTIR spectroscopy.

Sol-gel synthesis, phase composition, morphological and structural characterization of Ca10(PO4)6(OH)2: XRD, FTIR, SEM, 3D SEM and solid-state NMR studies

NASA Astrophysics Data System (ADS)

Kareiva, Simonas; Klimavicius, Vytautas; Momot, Aleksandr; Kausteklis, Jonas; Prichodko, Aleksandra; Dagys, Laurynas; Ivanauskas, Feliksas; Sakirzanovas, Simas; Balevicius, Vytautas; Kareiva, Aivaras

2016-09-01

Aqueous sol-gel chemistry route based on ammonium-hydrogen phosphate as the phosphorus precursor, calcium acetate monohydrate as source of calcium ions, and 1,2-ethylendiaminetetraacetic acid (EDTA), or 1,2-diaminocyclohexanetetracetic acid (DCTA), or tartaric acid (TA), or ethylene glycol (EG), or glycerol (GL) as complexing agents have been used to prepare calcium hydroxyapatite (Ca10(PO4)6(OH)2, CHAp). The phase transformations, composition, and structural changes in the polycrystalline samples were studied by infrared spectroscopy (FTIR), X-ray powder diffraction analysis (XRD), and scanning electron microscopy (SEM). The local short-range (nano- and mezo-) scale effects in CHAp were studied using solid-state NMR spectroscopy. The spatial 3D data from the SEM images of CHAp samples obtained by TA, EG and GL sol-gel routes were recovered for the first time to our knowledge.

Preparation, crystal structure, vibrational spectral and density functional studies of bis (4-nitrophenol)-2,4,6-triamino-1,3,5-triazine monohydrate

NASA Astrophysics Data System (ADS)

Kanagathara, N.; Marchewka, M. K.; Drozd, M.; Renganathan, N. G.; Gunasekaran, S.; Anbalagan, G.

2013-10-01

An organic-organic salt, bis (4-nitrophenol) 2,4,6-triamino 1,3,5-triazine monohydrate (BNPM) has been prepared by slow evaporation technique at room temperature. Single crystal X-ray diffraction analysis reveals that the compound crystallizes in triclinic system with centrosymmetric space group P-1. IR and Raman spectra of BNPM have been recorded and analyzed. The study has been extended to confocal Raman spectral analysis. Band assignments have been made for the melamine and p-nitrophenol molecules. Vibrational spectra have also been discussed on the basis of quantum chemical density functional theory calculations using Firefly (PC GAMESS) Version 7.1 G. Vibrational frequencies are calculated and scaled values are compared with the experimental one. The Mulliken charges, HOMO-LUMO orbital energies are calculated and analyzed. The chemical structure of the compound was established by 1H NMR and 13C NMR spectra.

Synthesis, crystal structure and biological activity of the Schiff base organotin(IV) complexes based on salicylaldehyde-o-aminophenol

NASA Astrophysics Data System (ADS)

Tan, Yu-Xing; Zhang, Zhi-Jian; Liu, Yang; Yu, Jiang-Xi; Zhu, Xiao-Ming; Kuang, Dai-Zhi; Jiang, Wu-Jiu

2017-12-01

Schiff base organotin(IV) complexes C1 ∼ C5b have been synthesized via the reaction of the substituted salicylaldehyde-o-aminophenol Schiff base ligands (L1 ∼ L3) with the dibenzyltin dichloride, n-butyltin trichloride or dibutyltin oxide, respectively. The complexes have been characterized by IR, UV-Vis, 1H NMR, 13C NMR spectra, elemental analysis and the crystal structures have been determined by X-ray diffraction. The anticancer activity of the Schiff base ligand and complexes C1 ∼ C5b against five species of cancer cell which are Hela, MCF7, HepG2, Colo205, NCIsbnd H460 were tested respectively, the tests showed that C1 ∼ C5b exhibited significant anticancer activity for the cancer cells in comparison with the ligand, and the activity was greater than carboplatin.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petersen, Line Boisen; Lipton, Andrew S.; Zorin, Vadim

Ordering of gallium(III) in a series of magnesium gallium (MgGa) layered double hydroxides (LDHs), [Mg{sub 1−x}Ga{sub x}(OH){sub 2}(NO{sub 3}){sub x}·yH{sub 2}O] was investigated using solid-state {sup 1}H and {sup 71}Ga NMR spectroscopy as well as powder X-ray diffraction. Three different proton environments from Mg{sub 3}-OH, Mg{sub 2}Ga-OH and intergallery water molecules were assigned and quantified using ({sup 1}H,{sup 71}Ga) HETCOR and {sup 1}H MAS NMR. A single {sup 71}Ga site originating from the unique Ga site in the MgGa LDH's was observed in {sup 71}Ga MAS and 3QMAS NMR spectra. Both {sup 1}H MAS NMR spectra recorded at 21.1 Tmore » (900 MHz) and elemental analysis show that the synthesized MgGa LDH's had a lower Mg:Ga ratio than that of the starting reactant solution. The origin of this is the formation of soluble [Ga(OH){sub 4}]{sup −} complexes formed during synthesis, and not due to formation of insoluble gallium (oxy)hydroxides. No sign of Ga-O-Ga connectivities or defects were detected for the MgGa LDH's. - Graphical abstract: Two types of hydroxides groups are observed in magnesium gallium layered double hydroxides revealing an ordering of Ga in the cation layer. - Highlights: • Ga is ordered in our magnesium gallium layered double hydroxides. • Ga depletion due to formation of soluble Ga complexes during synthesis. • No sign of Ga rich regions in magnesium gallium LDHs. • Solid state {sup 1}H and {sup 71}Ga give detailed insight into the structure.« less

Diffractive-refractive optics: (+,-,-,+) X-ray crystal monochromator with harmonics separation.

PubMed

Hrdý, Jaromír; Mikulík, Petr; Oberta, Peter

2011-03-01

A new kind of two channel-cut crystals X-ray monochromator in dispersive (+,-,-,+) position which spatially separates harmonics is proposed. The diffracting surfaces are oriented so that the diffraction is inclined. Owing to refraction the diffracted beam is sagittally deviated. The deviation depends on wavelength and is much higher for the first harmonics than for higher harmonics. This leads to spatial harmonics separation. The idea is supported by ray-tracing simulation.

The first naphthosemiquinone complex of K+ with vitamin K3 analog: Experiment and density functional theory

NASA Astrophysics Data System (ADS)

Kathawate, Laxmi; Gejji, Shridhar P.; Yeole, Sachin D.; Verma, Prakash L.; Puranik, Vedavati G.; Salunke-Gawali, Sunita

2015-05-01

Synthesis and characterization of potassium complex of 2-hydroxy-3-methyl-1,4-naphthoquinone (phthiocol), the vitamin K3 analog, has been carried out using FT-IR, UV-Vis, 1H and 13C NMR, EPR, cyclic voltammetry and single crystal X-ray diffraction experiments combined with the density functional theory. It has been observed that naphthosemiquinone binds to two K+ ions extending the polymeric chain through bridging oxygens O(2) and O(3). The crystal network possesses hydrogen bonding interactions from coordinated water molecules showing water channels along the c-axis. 13C NMR spectra revealed that the complexation of phthiocol with potassium ion engenders deshielding of C(2) signals, which appear at δ = ∼14.6 ppm whereas those of C(3) exhibit up-field signals near δ ∼ 6.9 ppm. These inferences are supported by the M06-2x based density functional theory. Electrochemical experiments further suggest that reduction of naphthosemiquinone results in only a cathodic peak from catechol. A triplet state arising from interactions between neighboring phthiocol anion lead to a half field signal at g = 4.1 in the polycrystalline X-band EPR spectra at 133 K.

Room Temperature Elastic Moduli and Vickers Hardness of Hot-Pressed LLZO Cubic Garnet

DTIC Science & Technology

2012-01-01

polishing compounds, Leco, St. Joseph, MI). X - ray diffraction and scanning electron microscopy (SEM) The microstructure of the hot-pressed specimens...was examined on uncoated fracture surfaces by SEM with an accelerating voltage of 1 and 3 kV. Phase purity was evaluated from X - ray diffraction data...the micro- structure appeared to be homogenous for the two hot- pressed LLZO specimens included in this study (Fig. 1). X - ray diffraction confirmed that

Synthesis, spectra and X-ray crystallography of dipyridin-2-ylmethanone oxime and its CuX2(oxime)2 complexes: Thermal, Hirshfeld surface and DFT analysis

NASA Astrophysics Data System (ADS)

Warad, Ismail; Abdoh, Muneer; Al Ali, Anas; Shivalingegowda, Naveen; Kumara, Karthik; Zarrouk, Abdelkader; Lokanath, Neartur Krishnappagowda

2018-02-01

Dipyridin-2-ylmethanone oxime (C11H9N3O), was prepared using di-2-pyridyl ketone. The oxime ligand and its neutral CuX2 (oxime)2 (X = Cl or Br) complexes have been identified with the aid of several spectroscopic techniques such as: IR, EI-MS, EA, UV-visible, TG, 1H-NMR and finally the structure of the free oxime ligand was confirmed by X-ray diffraction studies. The oxime crystallizes in the monoclinic space group P21/c, with cell parameters a = 8.8811 (8) Å, b = 10.6362 (8) Å, c = 11.2050 (8) Å, β = 109.085 (4) º, V = 1000.26 (14) Å3 and Z = 4. The molecular conformation is stabilized by a strong intramolecular Osbnd H⋯N hydrogen bonding between the hydroxyl group of the oxime moiety and the nitrogen of the pyridine ring. Since the oxime structure was solved by XRD, the ligand structure parameters like bond length and angles were compared to the DFT computed one, the UV-visible to TD-SCF and Hirshfeld surface to MEP analysis.

Method for improve x-ray diffraction determinations of residual stress in nickel-base alloys

DOEpatents

Berman, Robert M.; Cohen, Isadore

1990-01-01

A process for improving the technique of measuring residual stress by x-ray diffraction in pieces of nickel-base alloys which comprises covering part of a predetermined area of the surface of a nickel-base alloy with a dispersion, exposing the covered and uncovered portions of the surface of the alloy to x-rays by way of an x-ray diffractometry apparatus, making x-ray diffraction determinations of the exposed surface, and measuring the residual stress in the alloy based on these determinations. The dispersion is opaque to x-rays and serves a dual purpose since it masks off unsatisfactory signals such that only a small portion of the surface is measured, and it supplies an internal standard by providing diffractogram peaks comparable to the peaks of the nickel alloy so that the alloy peaks can be very accurately located regardless of any sources of error external to the sample.

Crystal structure and density of helium to 232 kbar

NASA Technical Reports Server (NTRS)

Mao, H. K.; Wu, Y.; Jephcoat, A. P.; Hemley, R. J.; Bell, P. M.; Bassett, W. A.

1988-01-01

The properties of helium and hydrogen at high pressure are topics of great interest to the understanding of planetary interiors. These materials constitute 95 percent of the entire solar system. A technique was presented for the measurement of X-ray diffraction from single-crystals of low-Z condenses gases in a diamond-anvil cell at high pressure. The first such single-crystal X-ray diffraction measurements on solid hydrogen to 26.5 GPa were presented. The application of this technique to the problem of the crystal structure, equation of state, and phase diagram of solid helium is reported. Crucial for X-ray diffraction studies of these materials is the use of a synchrotron radiation source which provides high brillance, narrow collimation of the incident and diffracted X-ray beams to reduce the background noise, and energy-dispersive diffraction techniques with polychromatic (white) radiation, which provides high detection efficiency.

Boroxol rings from diffraction data on vitreous boron trioxide.

PubMed

Soper, Alan K

2011-09-14

There has been a considerable debate about the nature of the short range atomic order in vitreous B(2)O(3). Some authorities state that it is not possible to build a model of glassy boron oxide of the correct density containing a large number of six-membered rings which also fits experimental diffraction data, but recent computer simulations appear to overrule that view. To discover which view is correct I use empirical potential structure refinement (EPSR) on existing neutron and x-ray diffraction data to build two models of vitreous B(2)O(3). One of these consists only of single boron and oxygen atoms arranged in a network to reproduce the diffraction data as closely as possible. This model has less than 10% of boron atoms in boroxol rings. The second model is made up of an equimolar mixture of B(3)O(3) hexagonal ring 'molecules' and BO(3) triangular molecules, with no free boron or oxygen atoms. This second model therefore has 75% of the boron atoms in boroxol rings. It is found that both models give closely similar diffraction patterns, suggesting that the diffraction data in this case are not sensitive to the number of boroxol rings present in the structure. This reinforces recent Raman, ab initio, and NMR claims that the percentage of boroxol rings in this material may be as high as 75%. The findings of this study probably explain why some interpretations based on different simulation techniques only find a small fraction of boroxol rings. The results also highlight the power of EPSR for the extraction of accurate atomistic representations of amorphous structures, provided adequate additional, non-scattering data (such as Raman and NMR in this case) are available.

Persistent dopants and phase segregation in organolead mixed-halide perovskites

DOE PAGES

Rosales, Bryan A.; Men, Long; Cady, Sarah D.; ...

2016-07-25

Organolead mixed-halide perovskites such as CH 3NH 3PbX 3–aX' a (X, X' = I, Br, Cl) are interesting semiconductors because of their low cost, high photovoltaic power conversion efficiencies, enhanced moisture stability, and band gap tunability. Using a combination of optical absorption spectroscopy, powder X-ray diffraction (XRD), and, for the first time, 207Pb solid state nuclear magnetic resonance (ssNMR), we probe the extent of alloying and phase segregation in these materials. Because 207Pb ssNMR chemical shifts are highly sensitive to local coordination and electronic structure, and vary linearly with halogen electronegativity and band gap, this technique can provide the truemore » chemical speciation and composition of organolead mixed-halide perovskites. We specifically investigate samples made by three different preparative methods: solution phase synthesis, thermal annealing, and solid phase synthesis. 207Pb ssNMR reveals that nonstoichiometric dopants and semicrystalline phases are prevalent in samples made by solution phase synthesis. We show that these nanodomains are persistent after thermal annealing up to 200 °C. Further, a novel solid phase synthesis that starts from the parent, single-halide perovskites can suppress phase segregation but not the formation of dopants. Our observations are consistent with the presence of miscibility gaps and spontaneous spinodal decomposition of the mixed-halide perovskites at room temperature. This underscores how strongly different synthetic procedures impact the nanostructuring and composition of organolead halide perovskites. In conclusion, better optoelectronic properties and improved device stability and performance may be achieved through careful manipulation of the different phases and nanodomains present in these materials.« less

Persistent dopants and phase segregation in organolead mixed-halide perovskites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosales, Bryan A.; Men, Long; Cady, Sarah D.

Organolead mixed-halide perovskites such as CH 3NH 3PbX 3–aX' a (X, X' = I, Br, Cl) are interesting semiconductors because of their low cost, high photovoltaic power conversion efficiencies, enhanced moisture stability, and band gap tunability. Using a combination of optical absorption spectroscopy, powder X-ray diffraction (XRD), and, for the first time, 207Pb solid state nuclear magnetic resonance (ssNMR), we probe the extent of alloying and phase segregation in these materials. Because 207Pb ssNMR chemical shifts are highly sensitive to local coordination and electronic structure, and vary linearly with halogen electronegativity and band gap, this technique can provide the truemore » chemical speciation and composition of organolead mixed-halide perovskites. We specifically investigate samples made by three different preparative methods: solution phase synthesis, thermal annealing, and solid phase synthesis. 207Pb ssNMR reveals that nonstoichiometric dopants and semicrystalline phases are prevalent in samples made by solution phase synthesis. We show that these nanodomains are persistent after thermal annealing up to 200 °C. Further, a novel solid phase synthesis that starts from the parent, single-halide perovskites can suppress phase segregation but not the formation of dopants. Our observations are consistent with the presence of miscibility gaps and spontaneous spinodal decomposition of the mixed-halide perovskites at room temperature. This underscores how strongly different synthetic procedures impact the nanostructuring and composition of organolead halide perovskites. In conclusion, better optoelectronic properties and improved device stability and performance may be achieved through careful manipulation of the different phases and nanodomains present in these materials.« less

Rheo-NMR Measurements of Cocoa Butter Crystallized Under

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mudge, E.; Mazzanti, G

2009-01-01

Modifications of a benchtop NMR instrument were made to apply temperature control to a shearing NMR cell. This has enabled the determination in situ of the solid fat content (SFC) of cocoa butter under shearing conditions. The cocoa butter was cooled at 3 C/min to three final temperatures of 17.5, 20.0, and 22.5 C with applied shear rates between 45 and 720 s-1. Polymorphic transitions of the cocoa butter were determined using synchrotron X-ray diffraction with an identical shearing system constructed of Lexan. Sheared samples were shown to have accelerated phase transitions compared to static experiments. In experiments where formmore » V was confirmed to be the dominant polymorph, the final SFC averaged around 50%. However, when other polymorphic forms were formed, a lower SFC was measured because the final temperature was within the melting range of that polymorph and only partial crystallization happened. A shear rate of 720 s-1 delayed phase transitions, likely due to viscous heating of the sample. Pulsed NMR is an invaluable tool for determining the crystalline fraction in hydrogen containing materials, yet its use for fundamental and industrial research on fat or alkanes crystallization under shear has only recently been developed.« less

Structural investigation of porcine stomach mucin by X-ray fiber diffraction and homology modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Veluraja, K., E-mail: veluraja@msuniv.ac.in; Vennila, K.N.; Umamakeshvari, K.

Research highlights: {yields} Techniques to get oriented mucin fibre. {yields} X-ray fibre diffraction pattern for mucin. {yields} Molecular modeling of mucin based on X-ray fibre diffraction pattern. -- Abstract: The basic understanding of the three dimensional structure of mucin is essential to understand its physiological function. Technology has been developed to achieve orientated porcine stomach mucin molecules. X-ray fiber diffraction of partially orientated porcine stomach mucin molecules show d-spacing signals at 2.99, 4.06, 4.22, 4.7, 5.37 and 6.5 A. The high intense d-spacing signal at 4.22 A is attributed to the antiparallel {beta}-sheet structure identified in the fraction of themore » homology modeled mucin molecule (amino acid residues 800-980) using Nidogen-Laminin complex structure as a template. The X-ray fiber diffraction signal at 6.5 A reveals partial organization of oligosaccharides in porcine stomach mucin. This partial structure of mucin will be helpful in establishing a three dimensional structure for the whole mucin molecule.« less

Formation of crystalline Zn-Al layered double hydroxide precipitates on γ-alumina: the role of mineral dissolution.

PubMed

Li, Wei; Livi, Kenneth J T; Xu, Wenqian; Siebecker, Matthew G; Wang, Yujun; Phillips, Brian L; Sparks, Donald L

2012-11-06

To better understand the sequestration of toxic metals such as nickel (Ni), zinc (Zn), and cobalt (Co) as layered double hydroxide (LDH) phases in soils, we systematically examined the presence of Al and the role of mineral dissolution during Zn sorption/precipitation on γ-Al(2)O(3) (γ-alumina) at pH 7.5 using extended X-ray absorption fine structure spectroscopy (EXAFS), high-resolution transmission electron microscopy (HR-TEM), synchrotron-radiation powder X-ray diffraction (SR-XRD), and (27)Al solid-state NMR. The EXAFS analysis indicates the formation of Zn-Al LDH precipitates at Zn concentration ≥0.4 mM, and both HR-TEM and SR-XRD reveal that these precipitates are crystalline. These precipitates yield a small shoulder at δ(Al-27) = +12.5 ppm in the (27)Al solid-state NMR spectra, consistent with the mixed octahedral Al/Zn chemical environment in typical Zn-Al LDHs. The NMR analysis provides direct evidence for the existence of Al in the precipitates and the migration from the dissolution of γ-alumina substrate. To further address this issue, we compared the Zn sorption mechanism on a series of Al (hydr)oxides with similar chemical composition but differing dissolubility using EXAFS and TEM. These results suggest that, under the same experimental conditions, Zn-Al LDH precipitates formed on γ-alumina and corundum but not on less soluble minerals such as bayerite, boehmite, and gibbsite, which point outs that substrate mineral surface dissolution plays an important role in the formation of Zn-Al LDH precipitates.

A nearly on-axis spectroscopic system for simultaneously measuring UV-visible absorption and X-ray diffraction in the SPring-8 structural genomics beamline.

PubMed

Sakaguchi, Miyuki; Kimura, Tetsunari; Nishida, Takuma; Tosha, Takehiko; Sugimoto, Hiroshi; Yamaguchi, Yoshihiro; Yanagisawa, Sachiko; Ueno, Go; Murakami, Hironori; Ago, Hideo; Yamamoto, Masaki; Ogura, Takashi; Shiro, Yoshitsugu; Kubo, Minoru

2016-01-01

UV-visible absorption spectroscopy is useful for probing the electronic and structural changes of protein active sites, and thus the on-line combination of X-ray diffraction and spectroscopic analysis is increasingly being applied. Herein, a novel absorption spectrometer was developed at SPring-8 BL26B2 with a nearly on-axis geometry between the X-ray and optical axes. A small prism mirror was placed near the X-ray beamstop to pass the light only 2° off the X-ray beam, enabling spectroscopic analysis of the X-ray-exposed volume of a crystal during X-ray diffraction data collection. The spectrometer was applied to NO reductase, a heme enzyme that catalyzes NO reduction to N2O. Radiation damage to the heme was monitored in real time during X-ray irradiation by evaluating the absorption spectral changes. Moreover, NO binding to the heme was probed via caged NO photolysis with UV light, demonstrating the extended capability of the spectrometer for intermediate analysis.

Investigating the Effects of Low Temperature Annealing of Amorphous Corrosion Resistant Alloys.

DTIC Science & Technology

1980-11-01

Ray Diffraction.................................................... 6 Differential Scanning Calorimetry....................................... 9...17 LIST OF FIGURES Figure 1. X- Ray Diffraction Results From Fe32Ni 36Cr 4P 2 B Annealed for One Hour at...Various Temperatures (Cr Ka Radiation) ................................. 7 Figure 2. X- Ray Diffraction Results From FeU2NiaeCr14SieB Annealed for One

Evidence from x-ray and neutron powder diffraction patterns that the so-called icosahedral and decagonal quasicrystals of MnAl(6) and other alloys are twinned cubic crystals.

PubMed

Pauling, L

1987-06-01

It is shown that the x-ray powder diffraction patterns of rapidly quenched MnAl(6) and Mg(32)(Al,Zn)(49) and the neutron powder diffraction pattern of MnAl(6) are compatible with the proposed 820-atom primitive cubic structure [Pauling, L. (1987) Phys. Rev. Lett. 58, 365-368]. The values found for the edge of the unit cube are 23.365 A (x-ray) and 23.416 A (neutron) for MnAl(6) and 24.313 A (x-ray) for Mg(32)(Al,Zn)(49).

Evidence from x-ray and neutron powder diffraction patterns that the so-called icosahedral and decagonal quasicrystals of MnAl6 and other alloys are twinned cubic crystals

PubMed Central

Pauling, Linus

1987-01-01

It is shown that the x-ray powder diffraction patterns of rapidly quenched MnAl6 and Mg32(Al,Zn)49 and the neutron powder diffraction pattern of MnAl6 are compatible with the proposed 820-atom primitive cubic structure [Pauling, L. (1987) Phys. Rev. Lett. 58, 365-368]. The values found for the edge of the unit cube are 23.365 Å (x-ray) and 23.416 Å (neutron) for MnAl6 and 24.313 Å (x-ray) for Mg32(Al,Zn)49. PMID:16593841

Grafting C8-C16 alkyl groups altered the self-assembly and curcumin -loading properties of sodium caseinate in water.

PubMed

Zhang, Yaqiong; Yang, Puyu; Yao, Fangyi; Liu, Jie; Yu, Liangli Lucy

2018-02-01

The data presented here are related to the research article entitled "Synthesis and characterization of alkylated caseinate, and its structure-curcumin loading property relationship in water" (Zhang et al., 2018) [1]. This data article reports the detailed spectra information for 1 H NMR, 13 C NMR and UPLC-Q-TOF MS of the N-succinimidyl fatty acid esters with various alkyl chain lengths (Cn-NHSs, n = 8, 12, 14 and 16). 1 H NMR, 13 C NMR and UPLC-Q-TOF MS spectra for C16-NHS are shown as an example. Then the stacked 1 H NMR spectra of the obtained alkylated caseinates (Cn-caseinates, n = 8, 12, 14 and 16) are provided. The surface hydrophobicity index (S 0 ) of Cn-caseinates with different substitution degrees (SD) of alkyl groups is shown. Additionally, Visual appearances for the formed aqueous dispersions of curcumin-loaded native caseinate (NaCas) and Cn-caseinates self-assemblies are shown. X-ray diffraction patterns of curcumin, C16-caseinate, its physical mixture and curcumin-loaded C16-caseinate self-assemblies are examined. The re-dispersibility and short-term storage stability of the curcumin-loaded NaCas and C16-caseinate self-assemblies are also studied.

High-energy X-ray diffraction using the Pixium 4700 flat-panel detector.

PubMed

Daniels, J E; Drakopoulos, M

2009-07-01

The Pixium 4700 detector represents a significant step forward in detector technology for high-energy X-ray diffraction. The detector design is based on digital flat-panel technology, combining an amorphous Si panel with a CsI scintillator. The detector has a useful pixel array of 1910 x 2480 pixels with a pixel size of 154 microm x 154 microm, and thus it covers an effective area of 294 mm x 379 mm. Designed for medical imaging, the detector has good efficiency at high X-ray energies. Furthermore, it is capable of acquiring sequences of images at 7.5 frames per second in full image mode, and up to 60 frames per second in binned region of interest modes. Here, the basic properties of this detector applied to high-energy X-ray diffraction are presented. Quantitative comparisons with a widespread high-energy detector, the MAR345 image plate scanner, are shown. Other properties of the Pixium 4700 detector, including a narrow point-spread function and distortion-free image, allows for the acquisition of high-quality diffraction data at high X-ray energies. In addition, high frame rates and shutterless operation open new experimental possibilities. Also provided are the necessary data for the correction of images collected using the Pixium 4700 for diffraction purposes.

Crystallization and preliminary X-ray diffraction analysis of a chitin-binding domain of hyperthermophilic chitinase from Pyrococcus furiosus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakamura, Tsutomu; Ishikawa, Kazuhiko; Hagihara, Yoshihisa

The expression, purification and preliminary X-ray diffraction studies of a chitin-binding domain of the chitinase from P. furiosus are reported. The crystallization and preliminary X-ray diffraction analysis of the chitin-binding domain of chitinase from a hyperthermophilic archaeon, Pyrococcus furiosus, are reported. The recombinant protein was prepared using an Escherichia coli overexpression system and was crystallized by the hanging-drop vapour-diffusion method. An X-ray diffraction data set was collected to 1.70 Å resolution. The crystal belonged to space group P4{sub 3}2{sub 1}2 or P4{sub 1}2{sub 1}2. The unit-cell parameters were determined to be a = b = 48.8, c = 85.0 Å.

Long-Wavelength X-Ray Diffraction and Its Applications in Macromolecular Crystallography.

PubMed

Weiss, Manfred S

2017-01-01

For many years, diffraction experiments in macromolecular crystallography at X-ray wavelengths longer than that of Cu-K α (1.54 Å) have been largely underappreciated. Effects caused by increased X-ray absorption result in the fact that these experiments are more difficult than the standard diffraction experiments at short wavelengths. However, due to the also increased anomalous scattering of many biologically relevant atoms, important additional structural information can be obtained. This information, in turn, can be used for phase determination, for substructure identification, in molecular replacement approaches, as well as in structure refinement. This chapter reviews the possibilities and the difficulties associated with such experiments, and it provides a short description of two macromolecular crystallography synchrotron beam lines dedicated to long-wavelength X-ray diffraction experiments.

Establishment of the structural and enhanced physicochemical properties of the cocrystal-2-benzyl amino pyridine with oxalic acid

NASA Astrophysics Data System (ADS)

Sangeetha, M.; Mathammal, R.

2017-09-01

We report on a cocrystal of 2-(benzyl amino) pyridine (BAP) with oxalic acid (OA) in the ratio 1:1. The cocrystal was synthesised and single crystals were grown under slow evaporation technique at room temperature. Single crystal X-ray diffraction (SCXRD) analysis determined the structure of the cocrystal formed and it belongs to orthorhombic system with Cc space group. It was also subjected to X-ray Powder diffraction (XRPD) to confirm the cocrystal structure. Hirshfeld surfaces and fingerprints were plotted to analyze the intermolecular interactions. Spectroscopic techniques such as FTIR, FT-Raman and NMR were carried out to identify the functional groups present in the cocrystal. The bioactivity of the cocrystal was revealed from the UV-Vis analysis. Computational Density Functional Theory (DFT) was adopted at the B3LYP/6-31+G** level to calculate the optimized geometrical parameters and the vibrational frequencies of the cocrystal. The non-linear optical property of the cocrystal was revealed from the SHG test. The different types of interactions and delocalization of charge were analysed from Natural Bond Orbital (NBO) calculations. The HOMO-LUMO energies and MEP surface maps confirmed the pharmaceutical importance of the (1:1) BAPOA cocrystal. The cocrystal has been explored for the invitro antioxidant activity and insilico molecular docking studies.

Synthetic aspects, spectral, thermal studies and antimicrobial screening on bis(N,N-dimethyldithiocarbamato-S,S‧)antimony(III) complexes with oxo or thio donor ligands

NASA Astrophysics Data System (ADS)

Chauhan, H. P. S.; Carpenter, Jaswant; Joshi, Sapana

2014-09-01

The bis(N,N-dimethyldithiocarbamato-S,S‧)antimony(III) complexes have been obtained by the reaction of chloro bis(N,N-dimethyldithiocarbamato-S,S‧)antimony(III) with corresponding oxo or thio donor ligands such as sodium benzoate 1, sodium thioglycolate 2, phenol 3, sodium 1-propanethiolate 4, potassium thioacetate 5, sodium salicylate 6, ethane-1,2-dithiolate 7 and disodium oxalate 8. These complexes have been characterized by the physicochemical [melting point, molecular weight determination and elemental analysis (C, H, N, S and Sb)], spectral [UV-Visible, FT-IR, far IR, NMR (1H and 13C)], thermogravimetric (TG & DTA) analysis, ESI-Mass and powder X-ray diffraction studies. Thermogravimetric analysis of the complexes confirmed the final decomposition product as highly pure antimony sulfide (Sb2S3) and powder X-ray diffraction studies show that the complexes are in lower symmetry with monoclinic crystal lattice and nano-ranged particle size (11.51-20.82 nm). The complexes have also been screened against some bacterial and fungal strains for their antibacterial and antifungal activities and compared with standard drugs. These show that the complexes have greater activities against some human pathogenic bacteria and fungi than the activities of standard drugs.

Growth, optical, thermal, mechanical and dielectric studies of sodium succinate hexahydrate (β phase) single crystal: A promising third order NLO material

NASA Astrophysics Data System (ADS)

Mageshwari, P. S. Latha; Priya, R.; Krishnan, S.; Joseph, V.; Das, S. Jerome

2016-11-01

A third order nonlinear optical (NLO)single crystals of sodium succinate hexahydrate (SSH) (β phase) has been grown by a slow evaporation growth technique using aqueous solution at ambient temperature. The lattice parameters and morphology of SSH were determined by single crystal X-ray diffraction analysis. SSH crystallizes in centrosymmetric monoclinic system with space group P 21 / c and the crystalline purity was analyzed by powder X-ray diffraction analysis. The UV-vis-NIR spectrum reveals that the crystal is transparent in the entire visible region. The recorded FT-IR spectrum verified the presence of various functional groups in the material. NMR analysis of the grown crystal confirms the structural elucidation and detects the major and minor functional groups present in the title compound. ICP-OES analysis proved the presence of sodium in SSH. TG-DTA/DSCanalysis was used to investigate the thermal stability of the material. The dielectric permittivity and dielectric loss of SSH were carried out as a function of frequency for different temperatures and the results were discussed. The mechanical stability was evaluated from Vicker's microhardness test. The third order nonlinear optical properties of SSH has been investigated employing Z-scan technique with He-Ne laser operating at 632.8 nm wavelength.

New fluorescent azo-Schiff base Cu(II) and Zn(II) metal chelates; spectral, structural, electrochemical, photoluminescence and computational studies

NASA Astrophysics Data System (ADS)

Purtas, Fatih; Sayin, Koray; Ceyhan, Gokhan; Kose, Muhammet; Kurtoglu, Mukerrem

2017-06-01

A new Schiff base containing azo chromophore group obtained by condensation of 2-hydroxy-4-[(E)-phenyldiazenyl]benzaldehyde with 3,4-dimethylaniline (HL) are used for the syntheses of new copper(II) and zinc(II) chelates, [Cu(L)2], and [Zn(L)2], and characterized by physico-chemical and spectroscopic methods such as 1H and 13C NMR, IR, UV.-Vis. and elemental analyses. The solid state structure of the ligand was characterized by single crystal X-ray diffraction study. X-ray diffraction data was then used to calculate the harmonic oscillator model of aromaticity (HOMA) indexes for the rings so as to investigate of enol-imine and keto-amine tautomeric forms in the solid state. The phenol ring C10-C15 shows a considerable deviation from the aromaticity with HOMA value of 0.837 suggesting the shift towards the keto-amine tautomeric form in the solid state. The analytical data show that the metal to ligand ratio in the chelates was found to be 1:2. Theoretical calculations of the possible isomers of the ligand and two metal complexes are performed by using B3LYP method. Electrochemical and photoluminescence properties of the synthesized azo-Schiff bases were also investigated.

Novel furosemide cocrystals and selection of high solubility drug forms.

PubMed

Goud, N Rajesh; Gangavaram, Swarupa; Suresh, Kuthuru; Pal, Sharmistha; Manjunatha, Sulur G; Nambiar, Sudhir; Nangia, Ashwini

2012-02-01

Furosemide was screened in cocrystallization experiments with pharmaceutically acceptable coformer molecules to discover cocrystals of improved physicochemical properties, that is high solubility and good stability. Eight novel equimolar cocrystals of furosemide were obtained by liquid-assisted grinding with (i) caffeine, (ii) urea, (iii) p-aminobenzoic acid, (iv) acetamide, (v) nicotinamide, (vi) isonicotinamide, (vii) adenine, and (viii) cytosine. The product crystalline phases were characterized by powder x-ray diffraction, differential scanning calorimetry, infrared, Raman, near IR, and (13) C solid-state NMR spectroscopy. Furosemide-caffeine was characterized as a neutral cocrystal and furosemide-cytosine an ionic salt by single crystal x-ray diffraction. The stability of furosemide-caffeine, furosemide-adenine, and furosemide-cytosine was comparable to the reference drug in 10% ethanol-water slurry; there was no evidence of dissociation of the cocrystal to furosemide for up to 48 h. The other five cocrystals transformed to furosemide within 24 h. The solubility order for the stable forms is furosemide-cytosine > furosemide-adenine > furosemide-caffeine, and their solubilities are approximately 11-, 7-, and 6-fold higher than furosemide. The dissolution rates of furosemide cocrystals were about two times faster than the pure drug. Three novel furosemide compounds of higher solubility and good phase stability were identified in a solid form screen. Copyright © 2011 Wiley Periodicals, Inc.

Data processing software suite SITENNO for coherent X-ray diffraction imaging using the X-ray free-electron laser SACLA.

PubMed

Sekiguchi, Yuki; Oroguchi, Tomotaka; Takayama, Yuki; Nakasako, Masayoshi

2014-05-01

Coherent X-ray diffraction imaging is a promising technique for visualizing the structures of non-crystalline particles with dimensions of micrometers to sub-micrometers. Recently, X-ray free-electron laser sources have enabled efficient experiments in the `diffraction before destruction' scheme. Diffraction experiments have been conducted at SPring-8 Angstrom Compact free-electron LAser (SACLA) using the custom-made diffraction apparatus KOTOBUKI-1 and two multiport CCD detectors. In the experiments, ten thousands of single-shot diffraction patterns can be collected within several hours. Then, diffraction patterns with significant levels of intensity suitable for structural analysis must be found, direct-beam positions in diffraction patterns determined, diffraction patterns from the two CCD detectors merged, and phase-retrieval calculations for structural analyses performed. A software suite named SITENNO has been developed to semi-automatically apply the four-step processing to a huge number of diffraction data. Here, details of the algorithm used in the suite are described and the performance for approximately 9000 diffraction patterns collected from cuboid-shaped copper oxide particles reported. Using the SITENNO suite, it is possible to conduct experiments with data processing immediately after the data collection, and to characterize the size distribution and internal structures of the non-crystalline particles.

Data processing software suite SITENNO for coherent X-ray diffraction imaging using the X-ray free-electron laser SACLA

PubMed Central

Sekiguchi, Yuki; Oroguchi, Tomotaka; Takayama, Yuki; Nakasako, Masayoshi

2014-01-01

Coherent X-ray diffraction imaging is a promising technique for visualizing the structures of non-crystalline particles with dimensions of micrometers to sub-micrometers. Recently, X-ray free-electron laser sources have enabled efficient experiments in the ‘diffraction before destruction’ scheme. Diffraction experiments have been conducted at SPring-8 Angstrom Compact free-electron LAser (SACLA) using the custom-made diffraction apparatus KOTOBUKI-1 and two multiport CCD detectors. In the experiments, ten thousands of single-shot diffraction patterns can be collected within several hours. Then, diffraction patterns with significant levels of intensity suitable for structural analysis must be found, direct-beam positions in diffraction patterns determined, diffraction patterns from the two CCD detectors merged, and phase-retrieval calculations for structural analyses performed. A software suite named SITENNO has been developed to semi-automatically apply the four-step processing to a huge number of diffraction data. Here, details of the algorithm used in the suite are described and the performance for approximately 9000 diffraction patterns collected from cuboid-shaped copper oxide particles reported. Using the SITENNO suite, it is possible to conduct experiments with data processing immediately after the data collection, and to characterize the size distribution and internal structures of the non-crystalline particles. PMID:24763651

Synthesis, growth, structural, optical, spectral, thermal and mechanical studies of 4-methoxy 4-nitrostilbene (MONS): a new organic nonlinear optical single crystal.

PubMed

Dinakaran, Paul M; Bhagavannarayana, G; Kalainathan, S

2012-11-01

4-Methoxy 4-nitrostilbene (MONS), a new organic nonlinear optical material has been synthesized. Based on the solubility data good quality single crystal with dimensions up to 38×11×3 mm(3) has been grown by slow evaporation method using ethyl methyl ketone (MEK) as a solvent. Powder XRD confirms the crystalline property and also the diffraction planes have been indexed. The lattice parameters for the grown MONS crystals were determined by using single crystal X-ray diffraction analysis and it reveals that the crystal lattice system is triclinic. The crystalline perfection of the grown crystals has been analysed by high resolution X-ray diffraction (HRXRD) rocking curve measurements. Fourier transform infrared (FTIR) spectrum for powdered MONS sample confirms the functional groups present in the grown crystal. The UV-vis absorption spectrum has been recorded in the range of 190-1100 nm and the cut off wavelength 499 nm has been determined. The optical constants of MONS have been determined through UV-vis-NIR spectroscopy. The MONS crystals were further subjected to other characterizations. i.e., (1)H NMR, TG/DTA, photoluminescence and microhardness test. The Kurtz and Perry powder technique confirms the NLO property of the grown crystal and the SHG efficiency of MONS was found to be 1.55× greater than that of KDP crystal. Copyright © 2012 Elsevier B.V. All rights reserved.

Spectroscopic imaging, diffraction, and holography with x-ray photoemission

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1992-02-01

X-ray probes are capable of determining the spatial structure of an atom in a specific chemical state, over length scales from about a micron all the way down to atomic resolution. Examples of these probes include photoemission microscopy, energy-dependent photoemission diffraction, photoelectron holography, and X-ray absorption microspectroscopy. Although the method of image formation, chemical-state sensitivity, and length scales can be very different, these X-ray techniques share a common goal of combining a capability for structure determination with chemical-state specificity. This workshop will address recent advances in holographic, diffraction, and direct imaging techniques using X-ray photoemission on both theoretical and experimentalmore » fronts. A particular emphasis will be on novel structure determinations with atomic resolution using photoelectrons.« less

An instrument for in situ coherent x-ray studies of metal-organic vapor phase epitaxy of III-nitrides.

PubMed

Ju, Guangxu; Highland, Matthew J; Yanguas-Gil, Angel; Thompson, Carol; Eastman, Jeffrey A; Zhou, Hua; Brennan, Sean M; Stephenson, G Brian; Fuoss, Paul H

2017-03-01

We describe an instrument that exploits the ongoing revolution in synchrotron sources, optics, and detectors to enable in situ studies of metal-organic vapor phase epitaxy (MOVPE) growth of III-nitride materials using coherent x-ray methods. The system includes high-resolution positioning of the sample and detector including full rotations, an x-ray transparent chamber wall for incident and diffracted beam access over a wide angular range, and minimal thermal sample motion, giving the sub-micron positional stability and reproducibility needed for coherent x-ray studies. The instrument enables surface x-ray photon correlation spectroscopy, microbeam diffraction, and coherent diffraction imaging of atomic-scale surface and film structure and dynamics during growth, to provide fundamental understanding of MOVPE processes.

An instrument for in situ coherent x-ray studies of metal-organic vapor phase epitaxy of III-nitrides

NASA Astrophysics Data System (ADS)

Ju, Guangxu; Highland, Matthew J.; Yanguas-Gil, Angel; Thompson, Carol; Eastman, Jeffrey A.; Zhou, Hua; Brennan, Sean M.; Stephenson, G. Brian; Fuoss, Paul H.

2017-03-01

We describe an instrument that exploits the ongoing revolution in synchrotron sources, optics, and detectors to enable in situ studies of metal-organic vapor phase epitaxy (MOVPE) growth of III-nitride materials using coherent x-ray methods. The system includes high-resolution positioning of the sample and detector including full rotations, an x-ray transparent chamber wall for incident and diffracted beam access over a wide angular range, and minimal thermal sample motion, giving the sub-micron positional stability and reproducibility needed for coherent x-ray studies. The instrument enables surface x-ray photon correlation spectroscopy, microbeam diffraction, and coherent diffraction imaging of atomic-scale surface and film structure and dynamics during growth, to provide fundamental understanding of MOVPE processes.

Pestalactams A-C: novel caprolactams from the endophytic fungus Pestalotiopsis sp.

PubMed

Davis, Rohan A; Carroll, Anthony R; Andrews, Katherine T; Boyle, Glen M; Tran, Truc Linh; Healy, Peter C; Kalaitzis, John A; Shivas, Roger G

2010-04-21

Chemical investigations of a fermentation culture from the endophytic fungus Pestalotiopsis sp. yielded three novel caprolactams, pestalactams A-C (). The structures of were determined by analysis of 1D and 2D-NMR, UV, IR, and MS data. The structure of pestalactam A was confirmed following single crystal X-ray diffraction analysis. Pestalactams A-C are the first C-7 alkylated caprolactam natural products to be reported. Pestalactams A () and B () were tested against two different strains of the malaria parasite Plasmodium falciparum (3D7 and Dd2), and the mammalian cell lines, MCF-7 and NFF, and showed modest in vitro activity in all assays.

Synthesis, crystal growth, structural, thermal and optical properties of naphthalene picrate an organic NLO material.

PubMed

Chandramohan, A; Bharathikannan, R; Kandavelu, V; Chandrasekaran, J; Kandhaswamy, M A

2008-12-01

Crystalline substance of naphthalene picrate (NP) was synthesized and single crystals were grown using slow evaporation solution growth technique. The solubility of the naphthalene picrate complex was estimated using different solvents such as chloroform and benzene. The material was characterized by elemental analysis, powder X-ray diffraction (XRD), nuclear magnetic resonance (NMR) and fourier transform-infrared (FT-IR) techniques. The electronic absorption was studied through UV-vis spectrophotometer. Thermal behavior and stability of the crystal were studied using thermogravimetric (TG) and differential thermal analysis (DTA) techniques. The second harmonic generation (SHG) of the material was confirmed using Nd:YAG laser.

Cryochemical modification, activity, and toxicity of dioxidine

NASA Astrophysics Data System (ADS)

Vernaya, O. I.; Shabatin, V. P.; Shabatina, T. I.; Khvatov, D. I.; Semenov, A. M.; Yudina, T. P.; Danilov, V. S.

2017-02-01

Dioxidine nanoparticles are prepared via cryochemical modification of the pharmacopoeial dioxidine substance. The form of the cryomodified dioxidine is characterized by data from 1H NMR spectroscopy; X-ray diffraction analysis; such thermal analytical methods as TG and DSC; low-temperature argon adsorption; and transmission electron microscopy. It is shown that the cryomodified samples are synthesized in the form of dioxidine nanocrystals 50-300 nm in size, with a crystal structure differing from that of the initial pharmacopoeial substance. The prepared cryomodified dioxidine nanoparticles inhibit the growth of E. coli 52, S. aureus 144, M. cyaneum 98, and B. cereus 9 better than the initial pharmacopoeial substance, and have comparable chronic toxicity.

Dysidinoid A, an unusual meroterpenoid with anti-MRSA activity from the South China Sea sponge Dysidea sp.

PubMed

Jiao, Wei-Hua; Li, Jing; Liu, Qian; Xu, Ting-Ting; Shi, Guo-Hua; Yu, Hao-Bing; Yang, Fan; Han, Bing-Nan; Li, Min; Lin, Hou-Wen

2014-11-05

An unusual meroterpenoid, dysidinoid A (1), was isolated from the South China Sea sponge Dysidea sp. Its structure was elucidated by extensive spectroscopic methods including HRESIMS and 2D NMR, and its absolute configuration was determined by single-crystal X-ray diffraction analysis. Dysidinoid A (1) is the first meroterpenoid from Nature bearing a 9,4-friedodrime skeleton and a 2,5-dionepyrrole unit. Dysidinoid A (1) showed potent antibacterial activity against two strains of pathogenic bacteria methicillin-resistant Staphylococcus aureus (MRSA) with MIC90 values of 8.0 μg/mL against both.

Self-Assembled Novel BODIPY-Based Palladium Supramolecules and Their Cellular Localization.

PubMed

Gupta, Gajendra; Das, Abhishek; Park, Kyoung Chul; Tron, Artur; Kim, Hyunuk; Mun, Junyoung; Mandal, Nripendranath; Chi, Ki-Whan; Lee, Chang Yeon

2017-04-17

Four new palladium metal supramolecules with triangular/square architectures derived from boron dipyrromethane (BODIPY) ligands were synthesized by self-assembly and fully characterized by 1 H and 31 P NMR, electrospray ionization mass spectrometry, and single-crystal X-ray diffraction. These supramolecules were more cytotoxic to brain cancer (glioblastoma) cells than to normal lung fibroblasts. Their cytotoxicity to the glioblastoma cells was higher than that of a benchmark metal-based chemotherapy drug, cisplatin. The characteristic green fluorescence of the BODIPY ligands in these supramolecules permitted their intracellular visualization using confocal microscopy, and the compounds were localized in the cytoplasm and on the plasma membrane.

Analysis of molecular interactions in solid dosage forms; challenge to molecular pharmaceutics.

PubMed

Yamamoto, Keiji; Limwikrant, Waree; Moribe, Kunikazu

2011-01-01

The molecular states of active pharmaceutical ingredients (APIs) in pharmaceutical dosage forms strongly affect the properties and quality of a drug. Various important fundamental physicochemical studies were reviewed from the standpoint of molecular pharmaceutics. Mechanochemical effects were evaluated in mixtures of APIs and pharmaceutical additives. Amorphization, complex formation and nanoparticle formation are observed after grinding process depending on the combination of APIs and pharmaceutical additives. Sealed-heating method and mesoporous materials have been used to investigate drug molecular interactions in dosage forms. Molecular states have been investigated using powder X-ray diffraction, thermal analysis, IR, solid state fluorometry, and NMR. © 2011 Pharmaceutical Society of Japan

High-throughput screening for bioactive components from traditional Chinese medicine.

PubMed

Zhu, Yanhui; Zhang, Zhiyun; Zhang, Meng; Mais, Dale E; Wang, Ming-Wei

2010-12-01

Throughout the centuries, traditional Chinese medicine has been a rich resource in the development of new drugs. Modern drug discovery, which relies increasingly on automated high throughput screening and quick hit-to-lead development, however, is confronted with the challenges of the chemical complexity associated with natural products. New technologies for biological screening as well as library building are in great demand in order to meet the requirements. Here we review the developments in these techniques under the perspective of their applicability in natural product drug discovery. Methods in library building, component characterizing, biological evaluation, and other screening methods including NMR and X-ray diffraction are discussed.

Modeling the Structure of Helical Assemblies with Experimental Constraints in Rosetta.

PubMed

André, Ingemar

2018-01-01

Determining high-resolution structures of proteins with helical symmetry can be challenging due to limitations in experimental data. In such instances, structure-based protein simulations driven by experimental data can provide a valuable approach for building models of helical assemblies. This chapter describes how the Rosetta macromolecular package can be used to model homomeric protein assemblies with helical symmetry in a range of modeling scenarios including energy refinement, symmetrical docking, comparative modeling, and de novo structure prediction. Data-guided structure modeling of helical assemblies with experimental information from electron density, X-ray fiber diffraction, solid-state NMR, and chemical cross-linking mass spectrometry is also described.

Combined X-ray and neutron fibre diffraction studies of biological and synthetic polymers

NASA Astrophysics Data System (ADS)

Parrot, I. M.; Urban, V.; Gardner, K. H.; Forsyth, V. T.

2005-08-01

The fibrous state is a natural one for polymer molecules which tend to assume regular helical conformations rather than the globular structures characteristic of many proteins. Fibre diffraction therefore has broad application to the study of a wide range of biological and synthetic polymers. The purpose of this paper is to illustrate the general scope of the method and in particular to demonstrate the impact of a combined approach involving both X-ray and neutron diffraction methods. While the flux of modern X-ray synchrotron radiation sources allows high quality datasets to be recorded with good resolution within a very short space of time, neutron studies can provide unique information through the ability to locate hydrogen or deuterium atoms that are often difficult or impossible to locate using X-ray methods. Furthermore, neutron fibre diffraction methods can, through the ability to selectively label specific parts of a structure, be used to highlight novel aspects of polymer structure that can not be studied using X-rays. Two examples are given. The first describes X-ray and neutron diffraction studies of conformational transitions in DNA. The second describes structural studies of the synthetic high-performance polymer poly(p-phenylene terephthalamide) (PPTA), known commercially as Kevlar® or Twaron®.

Conceptual Design for Time-Resolved X-ray Diffraction in a Single Laser-Driven Compression Experiment

NASA Astrophysics Data System (ADS)

Benedetti, Laura Robin; Eggert, J. H.; Kilkenny, J. D.; Bradley, D. K.; Bell, P. M.; Palmer, N. E.; Rygg, J. R.; Boehly, T. R.; Collins, G. W.; Sorce, C.

2017-06-01

Since X-ray diffraction is the most definitive method for identifying crystalline phases of a material, it is an important technique for probing high-energy-density materials during laser-driven compression experiments. We are developing a design for collecting several x-ray diffraction datasets during a single laser-driven experiment, with a goal of achieving temporal resolution better than 1ns. The design combines x-ray streak cameras, for a continuous temporal record of diffraction, with fast x-ray imagers, to collect several diffraction patterns with sufficient solid angle range and resolution to identify crystalline texture. Preliminary experiments will be conducted at the Omega laser and then implemented at the National Ignition Facility. We will describe the status of the conceptual design, highlighting tradeoffs in the design process. We will also discuss the technical issues that must be addressed in order to develop a successful experimental platform. These include: Facility-specific geometric constraints such as unconverted laser light and target alignment; EMP issues when electronic diagnostics are close to the target; X-ray source requirements; and detector capabilities. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, LLNL-ABS-725146.

Structural and electrical characterisation of Li(2)O : TiO(2) : SnO(2) : P(2)O(5) electrolyte glass.

PubMed

Abrahams, Isaac; Hadzifejzovic, Emina; Dygas, Jozef R

2004-10-07

Glasses of general formula 50Li(2)O : xSnO(2) : (10 -x)TiO(2) : 40P(2)O(5)(0.0 < or = x < or = 10) were investigated by differential scanning calorimetry, X-ray diffraction and ac impedance, (31)P solid-state NMR and IR spectroscopies. Three isotropic resonances can be identified in the (31)P NMR spectra, which have been assigned to various phosphate species. Analysis of the ratios of integrated intensities in the (31)P spectra leads to models for the Ti and Sn coordination environments. Both TiO(2) and SnO(2) are found to be predominantly network forming with Ti and Sn proposed to be in five- and four-coordinate environments respectively. Analysis of ac impedance spectra collected at low temperatures reveals two forms of permittivity dispersion, viz: high frequency conductivity dispersion and Cole-Cole type relaxation of permittivity. The activation energy of the relaxation frequency of the permittivity dispersion is equal to that of the dc conductivity, which is consistent with cooperative motion of lithium ions. The results also suggest that the observed increase in conductivity with temperature appears to be mainly due to an increase in mobility rather than increase in carrier concentration.

IDATEN and G-SITENNO: GUI-assisted software for coherent X-ray diffraction imaging experiments and data analyses at SACLA.

PubMed

Sekiguchi, Yuki; Yamamoto, Masaki; Oroguchi, Tomotaka; Takayama, Yuki; Suzuki, Shigeyuki; Nakasako, Masayoshi

2014-11-01

Using our custom-made diffraction apparatus KOTOBUKI-1 and two multiport CCD detectors, cryogenic coherent X-ray diffraction imaging experiments have been undertaken at the SPring-8 Angstrom Compact free electron LAser (SACLA) facility. To efficiently perform experiments and data processing, two software suites with user-friendly graphical user interfaces have been developed. The first is a program suite named IDATEN, which was developed to easily conduct four procedures during experiments: aligning KOTOBUKI-1, loading a flash-cooled sample into the cryogenic goniometer stage inside the vacuum chamber of KOTOBUKI-1, adjusting the sample position with respect to the X-ray beam using a pair of telescopes, and collecting diffraction data by raster scanning the sample with X-ray pulses. Named G-SITENNO, the other suite is an automated version of the original SITENNO suite, which was designed for processing diffraction data. These user-friendly software suites are now indispensable for collecting a large number of diffraction patterns and for processing the diffraction patterns immediately after collecting data within a limited beam time.

Dynamical diffraction imaging (topography) with X-ray synchrotron radiation

NASA Technical Reports Server (NTRS)

Kuriyama, M.; Steiner, B. W.; Dobbyn, R. C.

1989-01-01

By contrast to electron microscopy, which yields information on the location of features in small regions of materials, X-ray diffraction imaging can portray minute deviations from perfect crystalline order over larger areas. Synchrotron radiation-based X-ray optics technology uses a highly parallel incident beam to eliminate ambiguities in the interpretation of image details; scattering phenomena previously unobserved are now readily detected. Synchrotron diffraction imaging renders high-resolution, real-time, in situ observations of materials under pertinent environmental conditions possible.

Development of Thin Films as Potential Structural Cathodes to Enable Multifunctional Energy-Storage Structural Composite Batteries for the U.S. Army’s Future Force

DTIC Science & Technology

2011-09-01

glancing angle X - ray diffraction (GAXRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and electrochemical...Emission SEM FWHM full width at half maximum GAXRD glancing angle X - ray diffraction H3COCH2CH2OH 2-methoxyethanol LiMn2O4 lithium manganese oxide...were characterized by scanning electron microscopy (SEM), X - ray diffraction (XRD), and atomic force microscopy (AFM). In addition,

Crystal Structure of Garnet-Related Li-Ion Conductor Li7–3xGaxLa3Zr2O12: Fast Li-Ion Conduction Caused by a Different Cubic Modification?

PubMed Central

2016-01-01

Li-oxide garnets such as Li7La3Zr2O12 (LLZO) are among the most promising candidates for solid-state electrolytes to be used in next-generation Li-ion batteries. The garnet-structured cubic modification of LLZO, showing space group Ia-3d, has to be stabilized with supervalent cations. LLZO stabilized with Ga3+ shows superior properties compared to LLZO stabilized with similar cations; however, the reason for this behavior is still unknown. In this study, a comprehensive structural characterization of Ga-stabilized LLZO is performed by means of single-crystal X-ray diffraction. Coarse-grained samples with crystal sizes of several hundred micrometers are obtained by solid-state reaction. Single-crystal X-ray diffraction results show that Li7–3xGaxLa3Zr2O12 with x > 0.07 crystallizes in the acentric cubic space group I-43d. This is the first definite record of this cubic modification for LLZO materials and might explain the superior electrochemical performance of Ga-stabilized LLZO compared to its Al-stabilized counterpart. The phase transition seems to be caused by the site preference of Ga3+. 7Li NMR spectroscopy indicates an additional Li-ion diffusion process for LLZO with space group I-43d compared to space group Ia-3d. Despite all efforts undertaken to reveal structure–property relationships for this class of materials, this study highlights the potential for new discoveries. PMID:27019548

Synthesis and properties of acetamidinium salts

PubMed Central

2011-01-01

Background Acetamidines are starting materials for synthesizing many chemical substances, such as imidazoles, pyrimidines and triazines, which are further used for biochemically active compounds as well as energetic materials. The aim of this study was to synthesise and characterise a range of acetamidinium salts in order to overcome the inconvenience connected with acetamidinium chloride, which is the only commercially available acetamidinium salt. Results Acetamidinium salts were synthesised and characterised by elemental analysis, mass spectrometry, NMR and - in the case of energetic salts - DTA. The structures of previously unknown acetamidinium salts were established by X-ray diffraction analysis. Hygroscopicities in 90% humidity of eight acetamidinium salts were evaluated. Conclusions The different values of hygroscopicity are corroborated by the structures determined by X-ray analysis. The acetamidinium salts with 2D layered structures (acetamidinium nitrate, formate, oxalate and dinitromethanide) show a lack of hygroscopicity, and the compounds with 3D type of structure (acetamidinium chloride, acetate, sulphate and perchlorate) and possessing rather large cavities are quite hygroscopic. PMID:22152129

Exploring the Nature of Cellulose Microfibrils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Su, Ying; Burger, Christian; Ma, Hongyang

2015-03-20

Ultrathin cellulose microfibril fractions were extracted from spruce wood powder using combined delignification, TEMPO-catalyzed oxidation, and sonication processes. Small-angle X-ray scattering of these microfibril fractions in a “dilute” aqueous suspension (concentration 0.077 wt %) revealed that their shape was in the form of nanostrip with 4 nm width and only about 0.5 nm thicknesses. We found that these dimensions were further confirmed by TEM and AFM measurements. The 0.5 nm thickness implied that the nanostrip could contain only a single layer of cellulose chains. At a higher concentration (0.15 wt %), SAXS analysis indicated that these nanostrips aggregated into amore » layered structure. The X-ray diffraction of samples collected at different preparation stages suggested that microfibrils were delaminated along the (110) planes from the Iβ cellulose crystals. Moreover, the degree of oxidation and solid-state 13C NMR characterizations indicated that, in addition to the surface molecules, some inner molecules of microfibrils were also oxidized, facilitating the delamination into cellulose nanostrips.« less

Exploring the nature of cellulose microfibrils.

PubMed

Su, Ying; Burger, Christian; Ma, Hongyang; Chu, Benjamin; Hsiao, Benjamin S

2015-04-13

Ultrathin cellulose microfibril fractions were extracted from spruce wood powder using combined delignification, TEMPO-catalyzed oxidation, and sonication processes. Small-angle X-ray scattering of these microfibril fractions in a "dilute" aqueous suspension (concentration 0.077 wt %) revealed that their shape was in the form of nanostrip with 4 nm width and only about 0.5 nm thicknesses. These dimensions were further confirmed by TEM and AFM measurements. The 0.5 nm thickness implied that the nanostrip could contain only a single layer of cellulose chains. At a higher concentration (0.15 wt %), SAXS analysis indicated that these nanostrips aggregated into a layered structure. The X-ray diffraction of samples collected at different preparation stages suggested that microfibrils were delaminated along the (11̅0) planes from the Iβ cellulose crystals. The degree of oxidation and solid-state (13)C NMR characterizations indicated that, in addition to the surface molecules, some inner molecules of microfibrils were also oxidized, facilitating the delamination into cellulose nanostrips.

Keto-enol tautomerism in asymmetric Schiff bases derived from p-phenylenediamine

NASA Astrophysics Data System (ADS)

Užarević, Krunoslav; Rubčić, Mirta; Stilinović, Vladimir; Kaitner, Branko; Cindrić, Marina

2010-12-01

Reaction of dehydroacetic acid and p-phenylenediamine afforded a monosubstituted Schiff base, I, with the other amino group free. In further reactions with various salicylaldehyde derivatives, I served as a precursor for synthesis of asymmetric bis-Schiff bases. The synthesized compounds are thus comprised of two subunits, dehydroacetic ( dha) and salicylidene ( sal), which are bridged by the phenylene linker. All products were investigated by means of elemental analysis, FT-IR and NMR spectroscopy, thermal methods, powder X-ray diffraction and, when possible, by single crystal X-ray crystallography. Structural and spectroscopic studies revealed that in the bis-products, the dha subunit adopts the keto-amino tautomeric form, while the sal subunit adopts the enol-imino form. Tautomeric forms were not affected if a methoxo group was introduced on the salicylidene ring. Both tautomeric subunits are stabilized by strong resonance-assisted hydrogen bonds, RAHB. The two subunits of the prepared bis-Schiff bases predominantly retain in solution the same tautomeric forms as found in the solid state.

Extraction and Physicochemical Characterization of a New Polysaccharide Obtained from the Fresh Fruits of Abelmoschus Esculentus

PubMed Central

Emeje, Martins; Isimi, Christiana; Byrn, Stephen; Fortunak, Joseph; Kunle, Olobayo; Ofoefule, Sabinus

2011-01-01

This paper is the first multi-scale characterization of the fluidize-dried gum extracted from the fresh fruits of the plant Abelmoschus esculentus. It describes the physical, thermal, sorptional and functional properties of this natural gum. Elemental analysis, scanning electron microscopy (SEM), particle size analysis, X-ray powder diffraction (XPRD), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), fourier transmittance infra red (FT-IR), and nuclear magnetic resonance (NMR) spectroscopy were used to characterize the gum sample. Abelmoschus Esculentus Gum (AEG) had a glass transition temperature (Tg) of 70°C and no melting peak. It showed a 14.91% loss in weight at 195°C. X-ray diffractogram showed numerous broad halos for AEG. Elemental analysis showed that AEG contains 39.5, 7.3, 51.8, and 1.4% carbon, hydrogen, oxygen and nitrogen respectively. The results obtained in this study established the fundamental characteristics of AEG and suggests its potential application in the food, cosmetic and pharmaceutical sectors. PMID:24250349

Response surface modeling for optimization heterocatalytic Fenton oxidation of persistence organic pollution in high total dissolved solid containing wastewater.

PubMed

Sekaran, G; Karthikeyan, S; Boopathy, R; Maharaja, P; Gupta, V K; Anandan, C

2014-01-01

The rice-husk-based mesoporous activated carbon (MAC) used in this study was precarbonized and activated using phosphoric acid. N2 adsorption/desorption isotherm, X-ray powder diffraction, electron spin resonance, X-ray photoelectron spectroscopy and scanning electron microscopy, transmission electron microscopy, (29)Si-NMR spectroscopy, and diffuse reflectance spectroscopy were used to characterize the MAC. The tannery wastewater carrying high total dissolved solids (TDS) discharged from leather industry lacks biodegradability despite the presence of dissolved protein. This paper demonstrates the application of free electron-rich MAC as heterogeneous catalyst along with Fenton reagent for the oxidation of persistence organic compounds in high TDS wastewater. The heterogeneous Fenton oxidation of the pretreated wastewater at optimum pH (3.5), H2O2 (4 mmol/L), FeSO4[Symbol: see text]7H2O (0.2 mmol/L), and time (4 h) removed chemical oxygen demand, biochemical oxygen demand, total organic carbon and dissolved protein by 86, 91, 83, and 90%, respectively.

Simultaneous X-ray fluorescence and scanning X-ray diffraction microscopy at the Australian Synchrotron XFM beamline

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, Michael W. M.; Phillips, Nicholas W.; van Riessen, Grant A.

2016-08-11

Owing to its extreme sensitivity, quantitative mapping of elemental distributionsviaX-ray fluorescence microscopy (XFM) has become a key microanalytical technique. The recent realisation of scanning X-ray diffraction microscopy (SXDM) meanwhile provides an avenue for quantitative super-resolved ultra-structural visualization. The similarity of their experimental geometries indicates excellent prospects for simultaneous acquisition. Here, in both step- and fly-scanning modes, robust, simultaneous XFM-SXDM is demonstrated.

An Excel Spreadsheet for a One-Dimensional Fourier Map in X-ray Crystallography

ERIC Educational Resources Information Center

Clegg, William

2004-01-01

The teaching of crystal structure determination with single-crystal X-ray diffraction at undergraduate level faces numerous challenges. Single-crystal X-ray diffraction is used in a vast range of chemical research projects and forms the basis for a high proportion of structural results that are presented to high-school, undergraduate, and graduate…

Laser-induced Multi-energy Processing in Diamond Growth

DTIC Science & Technology

2012-05-01

microscopy (SEM) and energy dispersive X - ray (EDX) measurements, Drs. Yi Liu and Shah Valloppilly from Nebraska Center for Materials and Nanoscience...NCMN) at UNL for help on X - Ray diffraction (XRD) measurements, and Professor Steve W. Martin and Dr. Young Sik Kim from the Department of Material...spectroscopy and X - ray diffraction ................... 62 4.4 Conclusions

Two-dimensional time-resolved X-ray diffraction study of liquid/solid fraction and solid particle size in Fe-C binary system with an electrostatic levitator furnace

NASA Astrophysics Data System (ADS)

Yonemura, M.; Okada, J.; Watanabe, Y.; Ishikawa, T.; Nanao, S.; Shobu, T.; Toyokawa, H.

2013-03-01

Liquid state provides functions such as matter transport or a reaction field and plays an important role in manufacturing processes such as refining, forging or welding. However, experimental procedures are significantly difficult for an observation of solidification process of iron and iron-based alloys in order to identify rapid transformations subjected to fast temperature evolution. Therefore, in order to study the solidification in iron and iron-based alloys, we considered a combination of high energy X-ray diffraction measurements and an electrostatic levitation method (ESL). In order to analyze the liquid/solid fraction, the solidification of melted spherical specimens was measured at a time resolution of 0.1 seconds during rapid cooling using the two-dimensional time-resolved X-ray diffraction. Furthermore, the observation of particle sizes and phase identification was performed on a trial basis using X-ray small angle scattering with X-ray diffraction.

Imaging single cells in a beam of live cyanobacteria with an X-ray laser.

PubMed

van der Schot, Gijs; Svenda, Martin; Maia, Filipe R N C; Hantke, Max; DePonte, Daniel P; Seibert, M Marvin; Aquila, Andrew; Schulz, Joachim; Kirian, Richard; Liang, Mengning; Stellato, Francesco; Iwan, Bianca; Andreasson, Jakob; Timneanu, Nicusor; Westphal, Daniel; Almeida, F Nunes; Odic, Dusko; Hasse, Dirk; Carlsson, Gunilla H; Larsson, Daniel S D; Barty, Anton; Martin, Andrew V; Schorb, Sebastian; Bostedt, Christoph; Bozek, John D; Rolles, Daniel; Rudenko, Artem; Epp, Sascha; Foucar, Lutz; Rudek, Benedikt; Hartmann, Robert; Kimmel, Nils; Holl, Peter; Englert, Lars; Duane Loh, Ne-Te; Chapman, Henry N; Andersson, Inger; Hajdu, Janos; Ekeberg, Tomas

2015-02-11

There exists a conspicuous gap of knowledge about the organization of life at mesoscopic levels. Ultra-fast coherent diffractive imaging with X-ray free-electron lasers can probe structures at the relevant length scales and may reach sub-nanometer resolution on micron-sized living cells. Here we show that we can introduce a beam of aerosolised cyanobacteria into the focus of the Linac Coherent Light Source and record diffraction patterns from individual living cells at very low noise levels and at high hit ratios. We obtain two-dimensional projection images directly from the diffraction patterns, and present the results as synthetic X-ray Nomarski images calculated from the complex-valued reconstructions. We further demonstrate that it is possible to record diffraction data to nanometer resolution on live cells with X-ray lasers. Extension to sub-nanometer resolution is within reach, although improvements in pulse parameters and X-ray area detectors will be necessary to unlock this potential.

Design, synthesis, structural characterization by IR, (1) H, (13) C, (15) N, 2D-NMR, X-ray diffraction and evaluation of a new class of phenylaminoacetic acid benzylidene hydrazines as pfENR inhibitors.

PubMed

Samal, Ramanuj P; Khedkar, Vijay M; Pissurlenkar, Raghuvir R S; Bwalya, Angela Gono; Tasdemir, Deniz; Joshi, Ramesh A; Rajamohanan, P R; Puranik, Vedavati G; Coutinho, Evans C

2013-06-01

Recent studies have revealed that plasmodial enoyl-ACP reductase (pfENR, FabI), one of the crucial enzymes in the plasmodial type II fatty acid synthesis II (FAS II) pathway, is a promising target for liver stage malaria infections. Hence, pfENR inhibitors have the potential to be used as causal malarial prophylactic agents. In this study, we report the design, synthesis, structural characterization and evaluation of a new class of pfENR inhibitors. The search for inhibitors began with a virtual screen of the iResearch database by molecular docking. Hits obtained from the virtual screen were ranked according to their Glide score. One hit was selected as a lead and modified to improve its binding to pfENR; from this, a series of phenylamino acetic acid benzylidene hydrazides were designed and synthesized. These molecules were thoroughly characterized by IR, (1) H, (13) C, (15) N, 2D-NMR (COSY, NOESY, (1) H-(13) C, (1) H-(15) N HSQC and HMBC), and X-ray diffraction. NMR studies revealed the existence of conformational/configurational isomers around the amide and imine functionalities. The major species in DMSO solution is the E, E form, which is in dynamic equilibrium with the Z, E isomer. In the solid state, the molecule has a completely extended conformation and forms helical structures that are stabilized by strong hydrogen bond interactions, forming a helical structure stabilized by N-H…O interactions, a feature unique to this class of compounds. Furthermore, detailed investigation of the NMR spectra indicated the presence of a minor impurity in most compounds. The structure of this impurity was deduced as an imidazoline-4-one derivative based on (1) H-(13) C and (1) H-(15) H HMBC spectra and was confirmed from the NOESY spectra. The molecules were screened for in vitro activity against recombinant pfENR enzyme by a spectrophotometric assay. Four molecules, viz. 17, 7, 10, and 12 were found to be active at 7, 8, 10, and 12 μm concentration, respectively, showing promising pfENR inhibitory potential. A classification model was derived based on a binary QSAR approach termed recursive partitioning (RP) to highlight structural characteristics that could be tuned to improve activity. © 2013 John Wiley & Sons A/S.

Synergic Investigation Of The Self-Assembly Structure And Mechanism Of Retroviral Capsid Proteins By Solid State NMR, Transmission Electron Microscopy And Multiscale simulation

DTIC Science & Technology

2017-03-29

310 helix. Green: this work. Cyans: solution NMR RSV CA structure in PDB entry 1D1D.[18] Magentas: X-ray crystallography structure of flat hexameric...to combine cryo-electron microscopy and X-ray crystallography , Methods, 49 (2009) 174-180. [8] K.Y. Chan, J. Gumbart, R. McGreevy, J.M. Watermeyer

Synthesis, molecular structure and spectroscopic investigations of novel fluorinated spiro heterocycles.

PubMed

Islam, Mohammad Shahidul; Al-Majid, Abdullah Mohammed; Barakat, Assem; Soliman, Saied M; Ghabbour, Hazem A; Quah, Ching Kheng; Fun, Hoong-Kun

2015-05-07

This paper describes an efficient and regioselective method for the synthesis of novel fluorinated spiro-heterocycles in excellent yield by cascade [5+1] double Michael addition reactions. The compounds 7,11-bis(4-fluorophenyl)-2,4-dimethyl- 2,4-diazaspiro[5.5] undecane-1,3,5,9-tetraone (3a) and 2,4-dimethyl-7,11-bis (4-(trifluoromethyl)phenyl)-2,4-diazaspiro[5.5]undecane-1,3,5,9-tetraone (3b) were characterized by single-crystal X-ray diffraction, FT-IR and NMR techniques. The optimized geometrical parameters, infrared vibrational frequencies and NMR chemical shifts of the studied compounds have also been calculated using the density functional theory (DFT) method, using Becke-3-Lee-Yang-Parr functional and the 6-311G(d,p) basis set. There is good agreement between the experimentally determined structural parameters, vibrational frequencies and NMR chemical shifts of the studied compounds and those predicted theoretically. The calculated natural atomic charges using NBO method showed higher polarity of 3a compared to 3b.The calculated electronic spectra are also discussed based on the TD-DFT calculations.

Structure and short time degradation studies of sodium zirconium phosphate ceramics loaded with simulated fast breeder (FBR) waste

NASA Astrophysics Data System (ADS)

Ananthanarayanan, A.; Ambashta, R. D.; Sudarsan, V.; Ajithkumar, T.; Sen, D.; Mazumder, S.; Wattal, P. K.

2017-04-01

Sodium zirconium phosphate (NZP) ceramics have been prepared using conventional sintering and hot isostatic pressing (HIP) routes. The structure of NZP ceramics, prepared using the HIP route, has been compared with conventionally sintered NZP using a combination of X-ray diffraction (XRD) and (31P and 23Na) nuclear magnetic resonance (NMR) spectroscopy techniques. It is observed that NZP with no waste loading is aggressive toward the steel HIP-can during hot isostatic compaction and significant fraction of cations from the steel enter the ceramic material. Waste loaded NZP samples (10 wt% simulated FBR waste) show significantly low can-interaction and primary NZP phase is evident in this material. Upon exposure of can-interacted and waste loaded NZP to boiling water and steam, 31P NMR does not detect any major modifications in the network structure. However, the 23Na NMR spectra indicate migration of Na+ ions from the surface and possible re-crystallization. This is corroborated by Small-Angle Neutron Scattering (SANS) data and Scanning Electron Microscopy (SEM) measurements carried out on these samples.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Xi; Wang, Shanshan; Ghiviriga, Ion

A novel synthetic method to create gold based metallo–oligomers/polymers via the combination of inorganic click (iClick) with intermolecular aurophilic interactions is demonstrated. Complexes [PEt 3Au] 4(μ-N 3C 2C 6H 5) (1) and [PPhMe 2Au] 43C 2C 6H 5) (2) and {[PEt 3Au] 4[(μ-N 3C 2) 2-9,9-dihexyl-9H-fluorene]} n (8) have been synthesized via iClick. The tetranuclear structures of 1 and 2, induced by aurophilic bonding, are confirmed in the solid state through single crystal X-ray diffraction experiments and in solution via variable temperature NMR spectroscopy. The extended 1D structure of 8 is constructed by aurophilic induced self-assembly. 1H DOSY NMR analysismore » reveals that the aurophilic bonds in 1, 2, and 8 are retained in the solution phase. The degree of polymerization within complex 8 is temperature and concentration dependent, as determined by 1H DOSY NMR. The complex 8 is a rare example of a solution stable higher ordered structure linked by aurophilic interactions.« less

125Te NMR Probes of Tellurium Oxide Crystals: Shielding-Structure Correlations.

PubMed

Garaga, Mounesha N; Werner-Zwanziger, Ulrike; Zwanziger, Josef W

2018-01-16

The local environments around tellurium atoms in a series of tellurium oxide crystals were probed by 125 Te solid-state NMR spectroscopy. Crystals with distinct TeO n units (n from 3 to 6), including Na 2 TeO 3 , α-TeO 2 and γ-TeO 2 , Te 2 O(PO 4 ) 2 , K 3 LaTe 2 O 9 , BaZnTe 2 O 7 , and CsYTe 3 O 8 were studied. The latter four were synthesized through a solid-state process. X-ray diffraction was used to confirm the successful syntheses. The 125 Te chemical shift was found to exhibit a strong linear correlation with the Te coordination number. The 125 Te chemical-shift components (δ 11 , δ 22 , and δ 33 ) of the TeO 4 units were further correlated to the O-Te-O-bond angles. With the aid of 125 Te NMR, it is likely that these relations can be used to estimate the coordination states of Te atoms in unknown Te crystals and glasses.

Probing hydrogen bond networks in half-sandwich Ru(II) building blocks by a combined 1H DQ CRAMPS solid-state NMR, XRPD, and DFT approach.

PubMed

Chierotti, Michele R; Gobetto, Roberto; Nervi, Carlo; Bacchi, Alessia; Pelagatti, Paolo; Colombo, Valentina; Sironi, Angelo

2014-01-06

The hydrogen bond network of three polymorphs (1α, 1β, and 1γ) and one solvate form (1·H2O) arising from the hydration-dehydration process of the Ru(II) complex [(p-cymene)Ru(κN-INA)Cl2] (where INA is isonicotinic acid), has been ascertained by means of one-dimensional (1D) and two-dimensional (2D) double quantum (1)H CRAMPS (Combined Rotation and Multiple Pulses Sequences) and (13)C CPMAS solid-state NMR experiments. The resolution improvement provided by homonuclear decoupling pulse sequences, with respect to fast MAS experiments, has been highlighted. The solid-state structure of 1γ has been fully characterized by combining X-ray powder diffraction (XRPD), solid-state NMR, and periodic plane-wave first-principles calculations. None of the forms show the expected supramolecular cyclic dimerization of the carboxylic functions of INA, because of the presence of Cl atoms as strong hydrogen bond (HB) acceptors. The hydration-dehydration process of the complex has been discussed in terms of structure and HB rearrangements.

Luminescent properties under X-ray excitation of Ba(1-x)PbxWO4 disordered solid solution

NASA Astrophysics Data System (ADS)

Bakiz, B.; Hallaoui, A.; Taoufyq, A.; Benlhachemi, A.; Guinneton, F.; Villain, S.; Ezahri, M.; Valmalette, J.-C.; Arab, M.; Gavarri, J.-R.

2018-02-01

A series of polycrystalline barium-lead tungstate Ba1-xPbxWO4 with 0 ≤ x ≤ 1 was synthesized using a classical solid-state method with thermal treatment at 1000 °C. These materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Raman (FT-Raman) spectroscopy. X-ray diffraction profile analyses were performed using Rietveld method. These materials crystallized in the scheelite tetragonal structure and behaved as quasi ideal solid solution. Raman spectroscopy confirmed the formation of the solid solution. Structural distortions were evidenced in X-ray diffraction profiles and in vibration Raman spectra. The scanning electron microscopy experiments showed large and rounded irregular grains. Luminescence experiments were performed under X-ray excitation. The luminescence emission profiles have been interpreted in terms of four Gaussian components, with a major contribution of blue emission. The integrated intensity of luminescence reached a maximum value in the composition range x = 0.3-0.6, in relation with distortions of crystal lattice.

Amorphous Phase Characterization Through X-Ray Diffraction Profile Modeling: Implications for Amorphous Phases in Gale Crater Rocks and Soils

NASA Technical Reports Server (NTRS)

Achilles, C. N.; Downs, G. W.; Downs, R. T.; Morris, R. V.; Rampe, E. B.; Ming, D. W.; Chipera, S. J.; Blake, D. F.; Vaniman, D. T.; Bristow, T. F.;

X-ray Diffraction, Big and Small

NASA Image and Video Library

2012-10-30

A conventional X-ray diffraction instrument left is the size of a large refrigerator, in contrast to the compact size of the Chemistry and Mineralogy CheMin instrument on NASA Curiosity rover top right.

Coherent diffraction of single Rice Dwarf virus particles using hard X-rays at the Linac Coherent Light Source

PubMed Central

Munke, Anna; Andreasson, Jakob; Aquila, Andrew; Awel, Salah; Ayyer, Kartik; Barty, Anton; Bean, Richard J.; Berntsen, Peter; Bielecki, Johan; Boutet, Sébastien; Bucher, Maximilian; Chapman, Henry N.; Daurer, Benedikt J.; DeMirci, Hasan; Elser, Veit; Fromme, Petra; Hajdu, Janos; Hantke, Max F.; Higashiura, Akifumi; Hogue, Brenda G.; Hosseinizadeh, Ahmad; Kim, Yoonhee; Kirian, Richard A.; Reddy, Hemanth K.N.; Lan, Ti-Yen; Larsson, Daniel S.D.; Liu, Haiguang; Loh, N. Duane; Maia, Filipe R.N.C.; Mancuso, Adrian P.; Mühlig, Kerstin; Nakagawa, Atsushi; Nam, Daewoong; Nelson, Garrett; Nettelblad, Carl; Okamoto, Kenta; Ourmazd, Abbas; Rose, Max; van der Schot, Gijs; Schwander, Peter; Seibert, M. Marvin; Sellberg, Jonas A.; Sierra, Raymond G.; Song, Changyong; Svenda, Martin; Timneanu, Nicusor; Vartanyants, Ivan A.; Westphal, Daniel; Wiedorn, Max O.; Williams, Garth J.; Xavier, Paulraj Lourdu; Yoon, Chun Hong; Zook, James

2016-01-01

Single particle diffractive imaging data from Rice Dwarf Virus (RDV) were recorded using the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS). RDV was chosen as it is a well-characterized model system, useful for proof-of-principle experiments, system optimization and algorithm development. RDV, an icosahedral virus of about 70 nm in diameter, was aerosolized and injected into the approximately 0.1 μm diameter focused hard X-ray beam at the CXI instrument of LCLS. Diffraction patterns from RDV with signal to 5.9 Ångström were recorded. The diffraction data are available through the Coherent X-ray Imaging Data Bank (CXIDB) as a resource for algorithm development, the contents of which are described here. PMID:27478984

Signal-to-noise and radiation exposure considerations in conventional and diffraction x-ray microscopy

DOE PAGES

Huang, Xiaojing; Miao, Huijie; Steinbrener, Jan; ...

2009-01-01

Using a signal-to-noise ratio estimation based on correlations between multiple simulated images, we compare the dose efficiency of two soft x-ray imaging systems: incoherent brightfield imaging using zone plate optics in a transmission x-ray microscope (TXM), and x-ray diffraction microscopy (XDM) where an image is reconstructed from the far-field coherent diffraction pattern. In XDM one must computationally phase weak diffraction signals; in TXM one suffers signal losses due to the finite numerical aperture and efficiency of the optics. In simulations with objects representing isolated cells such as yeast, we find that XDM has the potential for delivering equivalent resolution imagesmore » using fewer photons. As a result, this can be an important advantage for studying radiation-sensitive biological and soft matter specimens.« less

Utilizing broadband X-rays in a Bragg coherent X-ray diffraction imaging experiment

DOE PAGES

Cha, Wonsuk; Liu, Wenjun; Harder, Ross; ...

2016-07-26

A method is presented to simplify Bragg coherent X-ray diffraction imaging studies of complex heterogeneous crystalline materials with a two-stage screening/imaging process that utilizes polychromatic and monochromatic coherent X-rays and is compatible with in situ sample environments. Coherent white-beam diffraction is used to identify an individual crystal particle or grain that displays desired properties within a larger population. A three-dimensional reciprocal-space map suitable for diffraction imaging is then measured for the Bragg peak of interest using a monochromatic beam energy scan that requires no sample motion, thus simplifyingin situchamber design. This approach was demonstrated with Au nanoparticles and will enable,more » for example, individual grains in a polycrystalline material of specific orientation to be selected, then imaged in three dimensions while under load.« less

Coherent diffraction of single Rice Dwarf virus particles using hard X-rays at the Linac Coherent Light Source

DOE PAGES

Munke, Anna; Andreasson, Jakob; Aquila, Andrew; ...

2016-08-01

Single particle diffractive imaging data from Rice Dwarf Virus (RDV) were recorded using the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS). RDV was chosen as it is a well-characterized model system, useful for proof-of-principle experiments, system optimization and algorithm development. RDV, an icosahedral virus of about 70 nm in diameter, was aerosolized and injected into the approximately 0.1 μm diameter focused hard X-ray beam at the CXI instrument of LCLS. Diffraction patterns from RDV with signal to 5.9 Ångström were recorded. Here, the diffraction data are available through the Coherent X-ray Imaging Data Bank (CXIDB)more » as a resource for algorithm development, the contents of which are described here.« less

Influence of neutron irradiation on the microstructure of nuclear graphite: An X-ray diffraction study

NASA Astrophysics Data System (ADS)

Zhou, Z.; Bouwman, W. G.; Schut, H.; van Staveren, T. O.; Heijna, M. C. R.; Pappas, C.

2017-04-01

Neutron irradiation effects on the microstructure of nuclear graphite have been investigated by X-ray diffraction on virgin and low doses (∼ 1.3 and ∼ 2.2 dpa), high temperature (750° C) irradiated samples. The diffraction patterns were interpreted using a model, which takes into account the turbostratic disorder. Besides the lattice constants, the model introduces two distinct coherent lengths in the c-axis and the basal plane, that characterise the volumes from which X-rays are scattered coherently. The methodology used in this work allows to quantify the effect of irradiation damage on the microstructure of nuclear graphite seen by X-ray diffraction. The results show that the changes of the deduced structural parameters are in agreement with previous observations from electron microscopy, but not directly related to macroscopic changes.

Utilizing broadband X-rays in a Bragg coherent X-ray diffraction imaging experiment.

PubMed

Cha, Wonsuk; Liu, Wenjun; Harder, Ross; Xu, Ruqing; Fuoss, Paul H; Hruszkewycz, Stephan O

2016-09-01

A method is presented to simplify Bragg coherent X-ray diffraction imaging studies of complex heterogeneous crystalline materials with a two-stage screening/imaging process that utilizes polychromatic and monochromatic coherent X-rays and is compatible with in situ sample environments. Coherent white-beam diffraction is used to identify an individual crystal particle or grain that displays desired properties within a larger population. A three-dimensional reciprocal-space map suitable for diffraction imaging is then measured for the Bragg peak of interest using a monochromatic beam energy scan that requires no sample motion, thus simplifying in situ chamber design. This approach was demonstrated with Au nanoparticles and will enable, for example, individual grains in a polycrystalline material of specific orientation to be selected, then imaged in three dimensions while under load.

Time-spliced X-ray diffraction imaging of magnetism dynamics in a NdNiO3 thin film

NASA Astrophysics Data System (ADS)

Beyerlein, Kenneth R.

2018-03-01

Diffraction imaging of nonequilibrium dynamics at atomic resolution is becoming possible with X-ray free-electron lasers. However, there are unresolved problems with applying this method to objects that are confined in only one dimension. Here I show that reliable one-dimensional coherent diffraction imaging is possible by splicing together images recovered from different time delays in an optical pump X-ray probe experiment. The time and space evolution of antiferromagnetic order in a vibrationally excited complex oxide heterostructure is recovered from time-resolved measurements of a resonant soft X-ray diffraction peak. Midinfrared excitation of the substrate is shown to lead to a demagnetization front that propagates at a velocity exceeding the speed of sound, a critical observation for the understanding of driven phase transitions in complex condensed matter.

Coherent diffraction of single Rice Dwarf virus particles using hard X-rays at the Linac Coherent Light Source.

PubMed

Munke, Anna; Andreasson, Jakob; Aquila, Andrew; Awel, Salah; Ayyer, Kartik; Barty, Anton; Bean, Richard J; Berntsen, Peter; Bielecki, Johan; Boutet, Sébastien; Bucher, Maximilian; Chapman, Henry N; Daurer, Benedikt J; DeMirci, Hasan; Elser, Veit; Fromme, Petra; Hajdu, Janos; Hantke, Max F; Higashiura, Akifumi; Hogue, Brenda G; Hosseinizadeh, Ahmad; Kim, Yoonhee; Kirian, Richard A; Reddy, Hemanth K N; Lan, Ti-Yen; Larsson, Daniel S D; Liu, Haiguang; Loh, N Duane; Maia, Filipe R N C; Mancuso, Adrian P; Mühlig, Kerstin; Nakagawa, Atsushi; Nam, Daewoong; Nelson, Garrett; Nettelblad, Carl; Okamoto, Kenta; Ourmazd, Abbas; Rose, Max; van der Schot, Gijs; Schwander, Peter; Seibert, M Marvin; Sellberg, Jonas A; Sierra, Raymond G; Song, Changyong; Svenda, Martin; Timneanu, Nicusor; Vartanyants, Ivan A; Westphal, Daniel; Wiedorn, Max O; Williams, Garth J; Xavier, Paulraj Lourdu; Yoon, Chun Hong; Zook, James

2016-08-01

Single particle diffractive imaging data from Rice Dwarf Virus (RDV) were recorded using the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS). RDV was chosen as it is a well-characterized model system, useful for proof-of-principle experiments, system optimization and algorithm development. RDV, an icosahedral virus of about 70 nm in diameter, was aerosolized and injected into the approximately 0.1 μm diameter focused hard X-ray beam at the CXI instrument of LCLS. Diffraction patterns from RDV with signal to 5.9 Ångström were recorded. The diffraction data are available through the Coherent X-ray Imaging Data Bank (CXIDB) as a resource for algorithm development, the contents of which are described here.

Time-spliced X-ray diffraction imaging of magnetism dynamics in a NdNiO3 thin film.

PubMed

Beyerlein, Kenneth R

2018-02-27

Diffraction imaging of nonequilibrium dynamics at atomic resolution is becoming possible with X-ray free-electron lasers. However, there are unresolved problems with applying this method to objects that are confined in only one dimension. Here I show that reliable one-dimensional coherent diffraction imaging is possible by splicing together images recovered from different time delays in an optical pump X-ray probe experiment. The time and space evolution of antiferromagnetic order in a vibrationally excited complex oxide heterostructure is recovered from time-resolved measurements of a resonant soft X-ray diffraction peak. Midinfrared excitation of the substrate is shown to lead to a demagnetization front that propagates at a velocity exceeding the speed of sound, a critical observation for the understanding of driven phase transitions in complex condensed matter.

Preliminary small-angle X-ray scattering and X-ray diffraction studies of the BTB domain of lola protein from Drosophila melanogaster

NASA Astrophysics Data System (ADS)

Boyko, K. M.; Nikolaeva, A. Yu.; Kachalova, G. S.; Bonchuk, A. N.; Dorovatovskii, P. V.; Popov, V. O.

2017-11-01

The Drosophila genome has several dozens of transcription factors (TTK group) containing BTB domains assembled into octamers. The LOLA protein belongs to this family. The purification, crystallization, and preliminary X-ray diffraction and small-angle X-ray scattering (SAXS) studies of the BTB domain of this protein are reported. The crystallization conditions were found by the vapor-diffusion technique. A very low diffraction resolution (8.7 Å resolution) of the crystals was insufficient for the determination of the threedimensional structure of the BTB domain. The SAXS study demonstrated that the BTB domain of the LOLA protein exists as an octamer in solution.

Cryogenic x-ray diffraction microscopy utilizing high-pressure cryopreservation

NASA Astrophysics Data System (ADS)

Lima, Enju; Chushkin, Yuriy; van der Linden, Peter; Kim, Chae Un; Zontone, Federico; Carpentier, Philippe; Gruner, Sol M.; Pernot, Petra

2014-10-01

We present cryo x-ray diffraction microscopy of high-pressure-cryofixed bacteria and report high-convergence imaging with multiple image reconstructions. Hydrated D. radiodurans cells were cryofixed at 200 MPa pressure into ˜10-μm-thick water layers and their unstained, hydrated cellular environments were imaged by phasing diffraction patterns, reaching sub-30-nm resolutions with hard x-rays. Comparisons were made with conventional ambient-pressure-cryofixed samples, with respect to both coherent small-angle x-ray scattering and the image reconstruction. The results show a correlation between the level of background ice signal and phasing convergence, suggesting that phasing difficulties with frozen-hydrated specimens may be caused by high-background ice scattering.

Synchrotron X-ray powder diffraction data of LASSBio-1515: A new N-acylhydrazone derivative compound

NASA Astrophysics Data System (ADS)

Costa, F. N.; Braz, D.; Ferreira, F. F.; da Silva, T. F.; Barreiro, E. J.; Lima, L. M.; Colaço, M. V.; Kuplich, L.; Barroso, R. C.

2014-02-01

In this work, synchrotron X-ray powder diffraction data allowed for a successful indexing of LASSBio-1515 compound, candidate to analgesic and anti-inflammatory activity. X-ray powder diffraction data collected in transmission and high-throughput geometries were used to analyze this compound. The X-ray wavelength of the synchrotron radiation used in this study was determined to be λ=1.55054 Å. LASSBio-1515 was found to be monoclinic with space group P21/c and unit cell parameters a=11.26255(16) Å, b=12.59785(16) Å, c=8.8540(1) Å, β=90.5972(7)° and V=1256.17(3) Å3.

Synthesis and structure elucidation of a series of pyranochromene chalcones and flavanones using 1D and 2D NMR spectroscopy and X-ray crystallography.

PubMed

Pawar, Sunayna S; Koorbanally, Neil A

2014-06-01

A series of novel pyranochromene chalcones and corresponding flavanones were synthesized. This is the first report on the confirmation of the absolute configuration of chromene-based flavanones using X-ray crystallography. These compounds were characterized by 2D NMR spectroscopy, and their assignments are reported herein. The 3D structure of the chalcone 3b and flavanone 4g was determined by X-ray crystallography, and the structure of the flavanone was confirmed to be in the S configuration at C-2. Copyright © 2014 John Wiley & Sons, Ltd.

First X-ray crystal structure and internal reference diffusion-ordered NMR spectroscopy study of the prototypical Posner reagent, MeCu(SPh)Li(THF)3.

PubMed

Bertz, Steven H; Hardin, Richard A; Heavey, Thomas J; Jones, Daniel S; Monroe, T Blake; Murphy, Michael D; Ogle, Craig A; Whaley, Tara N

2013-07-29

Grow slow: The usual direct treatment of MeLi and CuSPh did not yield X-ray quality crystals of MeCu(SPh)Li. An indirect method starting from Me2CuLi⋅LiSPh and chalcone afforded the desired crystals by the slow reaction of the intermediate π-complex (see scheme). This strategy produced the first X-ray crystal structure of a Posner cuprate. A complementary NMR study showed that the contact ion pair was also the main species in solution. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Inhibition of 53BP1: Potential for Restoring Homologous Recombination In Ovarian Cancer Cells

DTIC Science & Technology

2017-08-01

crystallography ; NMR spectroscopy; Calorimetry 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF RESPONSIBLE...ray crystallography ; NMR spectroscopy; Calorimetry 3. ACCOMPLISHMENTS: The PI is reminded that the recipient organization is required to obtain...originally planned. Each aim combines structural studies using X-ray crystallography or nuclear magnetic resonance (NMR) spectroscopy and functional

High-speed classification of coherent X-ray diffraction patterns on the K computer for high-resolution single biomolecule imaging.

PubMed

Tokuhisa, Atsushi; Arai, Junya; Joti, Yasumasa; Ohno, Yoshiyuki; Kameyama, Toyohisa; Yamamoto, Keiji; Hatanaka, Masayuki; Gerofi, Balazs; Shimada, Akio; Kurokawa, Motoyoshi; Shoji, Fumiyoshi; Okada, Kensuke; Sugimoto, Takashi; Yamaga, Mitsuhiro; Tanaka, Ryotaro; Yokokawa, Mitsuo; Hori, Atsushi; Ishikawa, Yutaka; Hatsui, Takaki; Go, Nobuhiro

2013-11-01

Single-particle coherent X-ray diffraction imaging using an X-ray free-electron laser has the potential to reveal the three-dimensional structure of a biological supra-molecule at sub-nanometer resolution. In order to realise this method, it is necessary to analyze as many as 1 × 10(6) noisy X-ray diffraction patterns, each for an unknown random target orientation. To cope with the severe quantum noise, patterns need to be classified according to their similarities and average similar patterns to improve the signal-to-noise ratio. A high-speed scalable scheme has been developed to carry out classification on the K computer, a 10PFLOPS supercomputer at RIKEN Advanced Institute for Computational Science. It is designed to work on the real-time basis with the experimental diffraction pattern collection at the X-ray free-electron laser facility SACLA so that the result of classification can be feedback for optimizing experimental parameters during the experiment. The present status of our effort developing the system and also a result of application to a set of simulated diffraction patterns is reported. About 1 × 10(6) diffraction patterns were successfully classificatied by running 255 separate 1 h jobs in 385-node mode.

High-speed classification of coherent X-ray diffraction patterns on the K computer for high-resolution single biomolecule imaging

PubMed Central

Tokuhisa, Atsushi; Arai, Junya; Joti, Yasumasa; Ohno, Yoshiyuki; Kameyama, Toyohisa; Yamamoto, Keiji; Hatanaka, Masayuki; Gerofi, Balazs; Shimada, Akio; Kurokawa, Motoyoshi; Shoji, Fumiyoshi; Okada, Kensuke; Sugimoto, Takashi; Yamaga, Mitsuhiro; Tanaka, Ryotaro; Yokokawa, Mitsuo; Hori, Atsushi; Ishikawa, Yutaka; Hatsui, Takaki; Go, Nobuhiro

2013-01-01

Single-particle coherent X-ray diffraction imaging using an X-ray free-electron laser has the potential to reveal the three-dimensional structure of a biological supra-molecule at sub-nanometer resolution. In order to realise this method, it is necessary to analyze as many as 1 × 106 noisy X-ray diffraction patterns, each for an unknown random target orientation. To cope with the severe quantum noise, patterns need to be classified according to their similarities and average similar patterns to improve the signal-to-noise ratio. A high-speed scalable scheme has been developed to carry out classification on the K computer, a 10PFLOPS supercomputer at RIKEN Advanced Institute for Computational Science. It is designed to work on the real-time basis with the experimental diffraction pattern collection at the X-ray free-electron laser facility SACLA so that the result of classification can be feedback for optimizing experimental parameters during the experiment. The present status of our effort developing the system and also a result of application to a set of simulated diffraction patterns is reported. About 1 × 106 diffraction patterns were successfully classificatied by running 255 separate 1 h jobs in 385-node mode. PMID:24121336

Elucidating the Wavelength Dependence of Phonon Scattering in Nanoparticle-Matrix Composites using Phonon Spectroscopy

DTIC Science & Technology

2016-07-11

composites with x - ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Rutherford backscattering spectroscopy...RBS), particle-induced x - ray emission (PIXE), and energy dispersive x - ray spectroscopy (EDX). This work complements earlier works on CdSe...sample shows only In2Se3 and CdIn2Se4 XRD peaks (Figure 1.4e), it is stoichiometrically   Figure 1.4. X - ray diffraction patterns of (a) γ-In2Se3

Applications of High Throughput (Combinatorial) Methodologies to Electronic, Magnetic, Optical, and Energy-Related Materials

DTIC Science & Technology

2013-06-17

of the films without having to fabricate capacitors. In addition, the use of X - ray diffraction (XRD) analysis enabled Chikyow et al.40 to identify an...effects of Al doping and annealing on the thermal stabil- ity of the Y2O3/Si gate stack were studied by X - ray photoemission spectroscopy (XPS) and X - ray ...the major diffraction features in the phase distribution. For a given structural phase, the X - ray peak intensity allows one to track the compositional

Aplanatic and quasi-aplanatic diffraction gratings

DOEpatents

Hettrick, M.C.

1987-09-14

A reflection diffraction grating having a series of transverse minute grooves of progressively varying spacing along a concave surface enables use of such gratings for x-ray or longer wavelength imaging of objects. The variable groove spacing establishes aplanatism or substantially uniform magnetification across the optical aperture. The grating may be sued, for example, in x-ray microscopes or telescopes of the imaging type and in x-ray microprobed. Increased spatial resolution and field of view may be realized in x-ray imaging. 5 figs.

An instrument for in situ coherent x-ray studies of metal-organic vapor phase epitaxy of III-nitrides

DOE PAGES

Ju, Guangxu; Highland, Matthew J.; Yanguas-Gil, Angel; ...

2017-03-21

Here, we describe an instrument that exploits the ongoing revolution in synchrotron sources, optics, and detectors to enable in situ studies of metal-organic vapor phase epitaxy (MOVPE) growth of III-nitride materials using coherent x-ray methods. The system includes high-resolution positioning of the sample and detector including full rotations, an x-ray transparent chamber wall for incident and diffracted beam access over a wide angular range, and minimal thermal sample motion, giving the sub-micron positional stability and reproducibility needed for coherent x-ray studies. The instrument enables surface x-ray photon correlation spectroscopy, microbeam diffraction, and coherent diffraction imaging of atomic-scale surface and filmmore » structure and dynamics during growth, to provide fundamental understanding of MOVPE processes.« less

Towards shot-noise limited diffraction experiments with table-top femtosecond hard x-ray sources.

PubMed

Holtz, Marcel; Hauf, Christoph; Weisshaupt, Jannick; Salvador, Antonio-Andres Hernandez; Woerner, Michael; Elsaesser, Thomas

2017-09-01

Table-top laser-driven hard x-ray sources with kilohertz repetition rates are an attractive alternative to large-scale accelerator-based systems and have found widespread applications in x-ray studies of ultrafast structural dynamics. Hard x-ray pulses of 100 fs duration have been generated at the Cu K α wavelength with a photon flux of up to 10 9 photons per pulse into the full solid angle, perfectly synchronized to the sub-100-fs optical pulses from the driving laser system. Based on spontaneous x-ray emission, such sources display a particular noise behavior which impacts the sensitivity of x-ray diffraction experiments. We present a detailed analysis of the photon statistics and temporal fluctuations of the x-ray flux, together with experimental strategies to optimize the sensitivity of optical pump/x-ray probe experiments. We demonstrate measurements close to the shot-noise limit of the x-ray source.

Towards shot-noise limited diffraction experiments with table-top femtosecond hard x-ray sources

PubMed Central

Holtz, Marcel; Hauf, Christoph; Weisshaupt, Jannick; Salvador, Antonio-Andres Hernandez; Woerner, Michael; Elsaesser, Thomas

2017-01-01

Table-top laser-driven hard x-ray sources with kilohertz repetition rates are an attractive alternative to large-scale accelerator-based systems and have found widespread applications in x-ray studies of ultrafast structural dynamics. Hard x-ray pulses of 100 fs duration have been generated at the Cu Kα wavelength with a photon flux of up to 109 photons per pulse into the full solid angle, perfectly synchronized to the sub-100-fs optical pulses from the driving laser system. Based on spontaneous x-ray emission, such sources display a particular noise behavior which impacts the sensitivity of x-ray diffraction experiments. We present a detailed analysis of the photon statistics and temporal fluctuations of the x-ray flux, together with experimental strategies to optimize the sensitivity of optical pump/x-ray probe experiments. We demonstrate measurements close to the shot-noise limit of the x-ray source. PMID:28795079

X-ray shearing interferometer

DOEpatents

Koch, Jeffrey A [Livermore, CA

2003-07-08

An x-ray interferometer for analyzing high density plasmas and optically opaque materials includes a point-like x-ray source for providing a broadband x-ray source. The x-rays are directed through a target material and then are reflected by a high-quality ellipsoidally-bent imaging crystal to a diffraction grating disposed at 1.times. magnification. A spherically-bent imaging crystal is employed when the x-rays that are incident on the crystal surface are normal to that surface. The diffraction grating produces multiple beams which interfere with one another to produce an interference pattern which contains information about the target. A detector is disposed at the position of the image of the target produced by the interfering beams.

Drechmerin H, a novel 1(2), 2(18)-diseco indole diterpenoid from the fungus Drechmeria sp. as a natural agonist of human pregnane X receptor.

PubMed

Zhao, Jian-Chao; Luan, Zhi-Lin; Liang, Jia-Hao; Cheng, Zhong-Bin; Sun, Cheng-Peng; Wang, Ya-Li; Zhang, Meng-Yue; Zhang, Tian-Yuan; Wang, Yong; Yang, Tian-Mei; Wu, Ying-Ying; Zhang, Yi-Xuan; Zhao, Xin-Yu; Ma, Xiao-Chi

2018-05-09

A novel 1(2), 2(18)-diseco indole diterpenoid, drechmerin H (1), was isolated from the fermentation broth of Drechmeria sp. together with a new indole diterpenoid, 2'-epi terpendole A (3), and a known analogue, terpendole A (2). Their structures were determined by HRESIMS, 1D and 2D NMR, ECD, and X-ray single crystal diffraction analyses as well as quantum chemical calculation. The abosulte configuration of terpendole A (2) was determined for the first time. Compound 1 displayed the significant agonistic effect on pregnane X receptor (PXR) with EC 50 value of 134.91 ± 2.01 nM, and its interaction with PXR was investigated by molecular docking. Meantime, a plausible biosynthetic pathway for compounds 1-3 is also discussed in the present work. Copyright © 2018 Elsevier Inc. All rights reserved.

Symposium N: Materials and Devices for Thermal-to-Electric Energy Conversion

DTIC Science & Technology

2010-08-24

X - ray diffraction, transmission electron microscopy, scanning electron microscopy, and dynamic light scattering. Thermal conductivity measurements...SEM), X - ray diffraction (XRD) measurements as well as Raman spectroscopy. The results from these techniques indicate a clear modification...was examined by using scanning electron microscope (SEM; HITACHI S-4500 model) attached with an energy dispersive x - ray spectroscopy. The electrical

Resorcarene-based receptor: versatile behavior in its interaction with heavy and soft metal cations.

PubMed

Danil de Namor, Angela F; Chaaban, Jinane K; Piro, Oscar E; Castellano, Eduardo E

2006-02-09

Standard solution Gibbs energies, DeltasG degrees, of the resorcarene-based receptor 5,11,17,23-ethylthiomethylated calix[4]resorcarene, (characterized by 1H NMR and X-ray diffraction studies) in its monomeric state (established through partition experiments) in various solvents are for the first time reported in the area of resorcarene chemistry. Transfer Gibbs energies of from hexane (reference solvent) to other medium are calculated. Agreement between DeltatG degrees (referred to the pure solvents) and standard partition Gibbs energies, DeltapG degrees (solvent mutually saturated) is found. Cation-ligand interactions were investigated through 1H NMR (CD3CN and CD3OD) and conductometric titrations in acetonitrile and methanol. 1H NMR data revealed the sites of interaction of with the metal cation. The composition of the metal-ion complexes (Ag+ and Pb2+ in acetonitrile and Ag+ and Cu2+ in methanol) was established through conductometric titrations. Thus, complexes of 1:1 stoichiometry were formed between and Ag+ and Pb2+ in acetonitrile and Cu2+ in methanol. However, in moving from acetonitrile to methanol, the composition of the silver complex was altered. Thus, two metal cations are hosted by a unit of the ligand. As far as Cu2+ and in acetonitrile is concerned, conductance data suggest that metalates are formed in which up to four units of Cu2+ are taken up per unit of resorcarene. The contrasting behavior of with Cu2+ in acetonitrile relative to methanol is discussed. As far as mercury (II) is concerned, the unusual jump in conductance observed in the titration of Hg2+ with in acetonitrile and methanol after the formation of a multicharged complex (undefined composition) is attributed to the presence of highly charged smaller units (higher mobility) resulting from the departure of pendant arms from the resorcarene backbone. Isolation of these species followed by X-ray diffraction studies corroborated this statement. The thermodynamic characterization of metal-ion complexes of Ag+ and Pb2+ in acetonitrile and Cu2+ and Ag+ in methanol is reported. Final conclusions are given.

Hydrothermal Synthesis and Characterization of Ni-Al Montmorillonite-Like Phyllosilicates

PubMed Central

Reinholdt, Marc X.; Brendlé, Jocelyne; Tuilier, Marie-Hélène; Kaliaguine, Serge; Ambroise, Emmanuelle

2013-01-01

This work describes the first hydrothermal synthesis in fluoride medium of Ni-Al montmorillonite-like phyllosilicates, in which the only metallic elements in the octahedral sheet are Ni and Al. X-ray diffraction , chemical analysis, thermogravimetric and differential thermal analysis, scanning electron microscopy and transmission electron microscopy confirm that the synthesized samples are montmorillonite-like phyllosilicates having the expected chemical composition. The specific surface areas of the samples are relatively large (>100 m2 g−1) compared to naturally occurring montmorillonites. 29Si and 27Al nuclear magnetic resonance (NMR) indicate substitutions of Al for Si in the tetrahedral sheet. 19F NMR and Ni K-edge extended X-ray absorption fine structure (EXAFS) local probes highlight a clustering of the metal elements and of the vacancies in the octahedral sheet of the samples. These Ni-Al phyllosilicates exhibit a higher local order than in previously synthesized Zn-Al phyllosilicates. Unlike natural montmorillonites, where the distribution of transition metal cations ensures a charge equilibrium allowing a stability of the framework, synthetic montmorillonites entail clustering and instability of the lattice when the content of divalent element in the octahedral sheet exceeds ca. 20%. Synthesis of Ni-Al montmorillonite-like phyllosilicates, was successfully achieved for the first time. These new synthetic materials may find potential applications as catalysts or as materials with magnetic, optical or staining properties. PMID:28348321

Synthesis, characterization and cytotoxic activity of substituted benzyl iminoether Pt(II) complexes of the type cis- and trans-[PtCl2{E-N(H)=C(OMe)CH2-C6H4-p-R}2] (R=Me, OMe, F). X-ray structure of trans-[PtCl2{E-N(H)=C(OMe)CH2-C6H4-p-F}2].

PubMed

Mazzega Sbovata, Silvia; Bettio, Frazia; Marzano, Christine; Tassan, Augusto; Mozzon, Mirto; Bertani, Roberta; Benetollo, Franco; Michelin, Rino A

2008-04-01

New substituted benzyl iminoether derivatives of the type cis- and trans-[PtCl(2){E-N(H)C(OMe)CH(2)-C(6)H(4)-p-R}(2)] (R=Me (1a, 2a), OMe (3a, 4a), F (5a, 6a)) have been synthesized and characterized by elemental analyses, FT-IR spectroscopy and NMR techniques. The iminoether ligands are in the E configuration, which is stable in solution and in the solid state, as confirmed by the (1)H NMR data. Complex trans-[PtCl(2){E-N(H)C(OMe)CH(2)-C(6)H(4)-p-F}(2)] (6a) was also characterized by an X-ray diffraction study. Complexes 1a-6a have been tested against a panel of human tumor cell lines in order to evaluate their cytotoxic activity. cis-Isomers were significant more potent than the corresponding trans-isomers against all tumor cell lines tested; moreover, complexes 1a and 5a showed IC(50) values from about 2-fold to 6-fold lower than those exhibited by cisplatin, used as reference platinum anticancer drug.

Physicochemical properties of water-soluble polysaccharides from black cumin seeds.

PubMed

Trigui, Ines; Yaich, Héla; Sila, Assaâd; Cheikh-Rouhou, Salma; Bougatef, Ali; Blecker, Christophe; Attia, Hamadi; Ayadi, M A

2018-06-01

In the present work, water-soluble polysaccharides were isolated from black cumin seeds. Polysaccharides were characterized by their carbohydrate composition, molecular weight, thermal stability and by FTIR, NMR spectroscopy and X-ray diffraction. The surface, the functional and the antioxidant properties of black cumin water-soluble polysaccharides (BCWSP) were also investigated. BCWSP consisted mainly of galacturonic acid (30.20%), glucuronic acid (17.66%) and neutral sugar (22.99%). BCWSP was composed of high peak molecular weight. The FTIR spectrum obtained for BCWSP showed two most important absorptions, at 1659 and 1085 cm -1 , which corresponded to COO - of uronic acids and pyranose form, respectively. NMR spectroscopy data suggested that the BCWSP is probably a rhamnogalacturonan backbone with galactan and arabinan side chains. X-ray pattern revealed the semi-crystalline behavior of BCWSP. WHC and OHC of BCWSP were relatively high and varied with temperatures. The polysaccharide zeta potential was greatly affected by pH. Results indicated that the decrease of surface tension has influenced foaming and emulsifying capacities. The DPPH radical scavenging activity of the BCWSP was 63.25% at 1 mg/mL. The BCWSP displayed moderate reductive, β carotene bleaching and chelating abilities. Overall, our results suggested that BCWSP could be used as alternative additives in food and non-food products. Copyright © 2017. Published by Elsevier B.V.

In situ synthesis studies of silicon clathrates

NASA Astrophysics Data System (ADS)

Hutchins, Peter Thomas

Solid state clathrates have shown considerable potential as a new class of materials over the past 30 years. Experimental and theoretical studies have shown that precise tuning and synthetic control of these materials, may lead to desirable properties. Very little is known about the mechanism of formation of the clathrates and so the desire to have accurate synthetic control was, until now, unrealistic. This thesis address the problem using in situ synchrotron x-ray techniques. In this study, experiments were designed to utilise time-resolved in situ diffraction techniques and high temperature 23Na NMR, in efforts to understand the mechanism of formation for this class of expanded framework materials. A complex high vacuum capillary synthesis cell was designed for loading under inert conditions and operation under high vacuum at station 6.2 of the SRS Daresbury. The cell was designed to operate in conjunction with a custom made furnace capable of temperatures in excess of 1000 C, as well as a vacuum system capable of 10"5 bar. The clathrate system was studied in situ, using rapid data collection to elucidate the mechanism of formation. The data were analysed using Rietveld methods and showed a structural link between the monoclinic, C2/c, Zintl precursors and the cubic, Pm3n, clathrate I phase. The phases were found to be linked by relation of the sodium planes in the silicide and the sodium atoms resident at cages centres in the clathrate system. This evidence suggests the guest species is instrumental in formation of the clathrate structure by templating the formation of the cages in the structure. Solid state 23Na NMR was utilised to complete specially design experiments, similar to those complete in situ using synchrotron x-ray techniques. The experiments showed increased spherical symmetry of the alkali metal sites and suggested increased mobility of the guest atoms during heating. In addition, cyclic heating experiments using in situ diffraction showed reversible reintroduction of the guest species on heating and cooling, during formation and subsequent dissipation of the clathrate structure. The realisation of the synthesis of a guest free type II clathrate and the theoretical prediction of negative thermal expansion behaviour at low temperature prompted the use of laboratory x-ray diffraction and a liquid helium cryostat to test the prediction. Careful study of the region from 20 to 200 K showed a region of zero or negative thermal expansion in the predicted region the effect observed showed good agreement with theory.

Linking structural biology with genome research: Beamlines for the Berlin ``Protein Structure Factory'' initiative

NASA Astrophysics Data System (ADS)

Illing, Gerd; Saenger, Wolfram; Heinemann, Udo

2000-06-01

The Protein Structure Factory will be established to characterize proteins encoded by human genes or cDNAs, which will be selected by criteria of potential structural novelty or medical or biotechnological usefulness. It represents an integrative approach to structure analysis combining bioinformatics techniques, automated gene expression and purification of gene products, generation of a biophysical fingerprint of the proteins and the determination of their three-dimensional structures either by NMR spectroscopy or by X-ray diffraction. The use of synchrotron radiation will be crucial to the Protein Structure Factory: high brilliance and tunable wavelengths are prerequisites for fast data collection, the use of small crystals and multiwavelength anomalous diffraction (MAD) phasing. With the opening of BESSY II, direct access to a third-generation XUV storage ring source with excellent conditions is available nearby. An insertion device with two MAD beamlines and one constant energy station will be set up until 2001.

Investigation of Local Structures in Cation-ordered Microwave Dielectric A Solid-state NMR and First Principle Calculation Study

NASA Astrophysics Data System (ADS)

Kalfarisi, Rony G.

Solid-state Nuclear Magnetic Resonance (ssNMR) spectroscopy has proven to be a powerful method to probe the local structure and dynamics of a system. In powdered solids, the nuclear spins experience various anisotropic interactions which depend on the molecular orientation. These anisotropic interactions make ssNMR very useful as they give a specific appearance to the resonance lines of the spectra. The position and shape of these resonance lines can be related to local structure and dynamics of the system under study. My research interest has focused around studying local structures and dynamics of quadrupolar nuclei in materials using ssNMR spectroscopy. 7Li and 93Nb ssNMR magic angle spinning (MAS) spectra, acquired at 17.6 and 7.06 T, have been used to evaluate the structural and dynamical properties of cation-ordered microwave dielectric materials. Microwave dielectric materials are essential in the application of wireless telecommunication, biomedical engineering, and other scientific and industrial implementations that use radio and microwave signals. The study of the local environment with respect to average structure, such as X-ray diffraction study, is essential for the better understanding of the correlations between structures and properties of these materials. The investigation for short and medium range can be performed with the use of ssNMR techniques. Even though XRD results show cationic ordering at the B-site (third coordination sphere), NMR spectra show a presence of disorder materials. This was indicated by the observation of a distribution in NMR parameters derived from experimental . {93}Nb NMR spectraand supported by theoretical calculations.

In situ electrochemical high-energy X-ray diffraction using a capillary working electrode cell geometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, Matthias J.; Bedford, Nicholas M.; Jiang, Naisheng

The ability to generate new electrochemically active materials for energy generation and storage with improved properties will likely be derived from an understanding of atomic-scale structure/function relationships during electrochemical events. Here, the design and implementation of a new capillary electrochemical cell designed specifically forin situhigh-energy X-ray diffraction measurements is described. By increasing the amount of electrochemically active material in the X-ray path while implementing low-Zcell materials with anisotropic scattering profiles, an order of magnitude enhancement in diffracted X-ray signal over traditional cell geometries for multiple electrochemically active materials is demonstrated. This signal improvement is crucial for high-energy X-ray diffraction measurementsmore » and subsequent Fourier transformation into atomic pair distribution functions for atomic-scale structural analysis. As an example, clear structural changes in LiCoO 2under reductive and oxidative conditions using the capillary cell are demonstrated, which agree with prior studies. Accurate modeling of the LiCoO 2diffraction data using reverse Monte Carlo simulations further verifies accurate background subtraction and strong signal from the electrochemically active material, enabled by the capillary working electrode geometry.« less

In Situ 3D Coherent X-ray Diffraction Imaging of Shock Experiments: Possible?

NASA Astrophysics Data System (ADS)

Barber, John

2011-03-01

In traditional coherent X-ray diffraction imaging (CXDI), a 2D or quasi-2D object is illuminated by a beam of coherent X-rays to produce a diffraction pattern, which is then manipulated via a process known as iterative phase retrieval to reconstruct an image of the original 2D sample. Recently, there have been dramatic advances in methods for performing fully 3D CXDI of a sample from a single diffraction pattern [Raines et al, Nature 463 214-7 (2010)], and these methods have been used to image samples tens of microns in size using soft X-rays. In this work, I explore the theoretical possibility of applying 3D CXDI techniques to the in situ imaging of the interaction between a shock front and a polycrystal, a far more stringent problem. A delicate trade-off is required between photon energy, spot size, imaging resolution, and the dimensions of the experimental setup. In this talk, I will outline the experimental and computational requirements for performing such an experiment, and I will present images and movies from simulations of one such hypothetical experiment, including both the time-resolved X-ray diffraction patterns and the time-resolved sample imagery.

High spatial resolution X-ray and gamma ray imaging system using diffraction crystals

DOEpatents

Smither, Robert K [Hinsdale, IL

2011-05-17

A method and a device for high spatial resolution imaging of a plurality of sources of x-ray and gamma-ray radiation are provided. The device comprises a plurality of arrays, with each array comprising a plurality of elements comprising a first collimator, a diffracting crystal, a second collimator, and a detector.

Photoluminescence studies on Cd(1-x)Zn(x)S:Mn2+ nanocrystals.

PubMed

Sethi, Ruchi; Kumar, Lokendra; Pandey, A C

2009-09-01

Highly monodispersed, undoped and doped with Mn2+, binary and ternary (CdS, ZnS, Cd(1-x)Zn(x)S) compound semiconductor nanocrystals have been synthesized by co-precipitation method using citric acid as a stabilizer. As prepared sample are characterized by X-ray diffraction, Small angle X-ray scattering, Transmission electron microscope, Optical absorption and Photoluminescence spectroscopy, for their optical and structural properties. X-ray diffraction, Small angle X-ray scattering and Transmission electron microscope results confirm the preparation of monodispersed nanocrystals. Photoluminescence studies show a significant blue shift in the wavelength with an increasing concentration of Zn in alloy nanocrystals.

Observation of sagittal X-ray diffraction by surface acoustic waves in Bragg geometry.

PubMed

Vadilonga, Simone; Zizak, Ivo; Roshchupkin, Dmitry; Evgenii, Emelin; Petsiuk, Andrei; Leitenberger, Wolfram; Erko, Alexei

2017-04-01

X-ray Bragg diffraction in sagittal geometry on a Y-cut langasite crystal (La 3 Ga 5 SiO 14 ) modulated by Λ = 3 µm Rayleigh surface acoustic waves was studied at the BESSY II synchrotron radiation facility. Owing to the crystal lattice modulation by the surface acoustic wave diffraction, satellites appear. Their intensity and angular separation depend on the amplitude and wavelength of the ultrasonic superlattice. Experimental results are compared with the corresponding theoretical model that exploits the kinematical diffraction theory. This experiment shows that the propagation of the surface acoustic waves creates a dynamical diffraction grating on the crystal surface, and this can be used for space-time modulation of an X-ray beam.

Observation of sagittal X-ray diffraction by surface acoustic waves in Bragg geometry1

PubMed Central

Vadilonga, Simone; Zizak, Ivo; Roshchupkin, Dmitry; Evgenii, Emelin; Petsiuk, Andrei; Leitenberger, Wolfram; Erko, Alexei

2017-01-01

X-ray Bragg diffraction in sagittal geometry on a Y-cut langasite crystal (La3Ga5SiO14) modulated by Λ = 3 µm Rayleigh surface acoustic waves was studied at the BESSY II synchrotron radiation facility. Owing to the crystal lattice modulation by the surface acoustic wave diffraction, satellites appear. Their intensity and angular separation depend on the amplitude and wavelength of the ultrasonic superlattice. Experimental results are compared with the corresponding theoretical model that exploits the kinematical diffraction theory. This experiment shows that the propagation of the surface acoustic waves creates a dynamical diffraction grating on the crystal surface, and this can be used for space–time modulation of an X-ray beam. PMID:28381976

Study of the gel films of Acetobacter Xylinum cellulose and its modified samples by {sup 1}H NMR cryoporometry and small-angle X-ray scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Babushkina, T. A.; Klimova, T. P.; Shtykova, E. V.

2010-03-15

Gel films of Acetobacter Xylinum cellulose and its modified samples have been investigated by 1H nuclear magnetic resonance (NMR) cryoporometry and small-angle X-ray scattering. The joint use of these two methods made it possible to characterize the sizes of aqueous pores in gel films and estimate the sizes of structural inhomogeneities before and after the sorption of polyvinylpyrrolidone and Se{sub 0} nanoparticles (stabilized by polyvinylpyrrolidone) into the films. According to small-angle X-ray scattering data, the sizes of inhomogeneities in a gel film change only slightly upon the sorption of polyvinylpyrrolidone and nanoparticles. The impregnated material is sorbed into water-filled cavitiesmore » that are present in the gel film. {sup 1}H NMR cryoporometry allowed us to reveal the details of changes in the sizes of small aqueous pores during modifications.« less

Method for improving x-ray diffraction determinations of residual stress in nickel-base alloys

DOEpatents

Berman, R.M.; Cohen, I.

1988-04-26

A process for improving the technique of measuring residual stress by x-ray diffraction in pieces of nickel-base alloys is discussed. Part of a predetermined area of the surface of a nickel-base alloy is covered with a dispersion. This exposes the covered and uncovered portions of the surface of the alloy to x-rays by way of an x-ray diffractometry apparatus, making x-ray diffraction determinations of the exposed surface, and measuring the residual stress in the alloy based on these determinations. The dispersion is opaque to x-rays and serves a dual purpose, since it masks off unsatisfactory signals such that only a small portion of the surface is measured, and it supplies an internal standard by providing diffractogram peaks comparable to the peaks of the nickel alloy so that the alloy peaks can be very accurately located regardless of any sources of error external to the sample. 2 figs.

Dynamic x-ray imaging of laser-driven nanoplasmas

NASA Astrophysics Data System (ADS)

Fennel, Thomas

2016-05-01

A major promise of current x-ray science at free electron lasers is the realization of unprecedented imaging capabilities for resolving the structure and ultrafast dynamics of matter with nanometer spatial and femtosecond temporal resolution or even below via single-shot x-ray diffraction. Laser-driven atomic clusters and nanoparticles provide an ideal platform for developing and demonstrating the required technology to extract the ultrafast transient spatiotemporal dynamics from the diffraction images. In this talk, the perspectives and challenges of dynamic x-ray imaging will be discussed using complete self-consistent microscopic electromagnetic simulations of IR pump x-ray probe imaging for the example of clusters. The results of the microscopic particle-in-cell simulations (MicPIC) enable the simulation-assisted reconstruction of corresponding experimental data. This capability is demonstrated by converting recently measured LCLS data into a ultrahigh resolution movie of laser-induced plasma expansion. Finally, routes towards reaching attosecond time resolution in the visualization of complex dynamical processes in matter by x-ray diffraction will be discussed.

Infrastructure development for radioactive materials at the NSLS-II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sprouster, D. J.; Weidner, R.; Ghose, S. K.

2018-02-01

The X-ray Powder Diffraction (XPD) Beamline at the National Synchrotron Light Source-II is a multipurpose instrument designed for high-resolution, high-energy X-ray scattering techniques. In this article, the capabilities, opportunities and recent developments in the characterization of radioactive materials at XPD are described. The overarching goal of this work is to provide researchers access to advanced synchrotron techniques suited to the structural characterization of materials for advanced nuclear energy systems. XPD is a new beamline providing high photon flux for X-ray Diffraction, Pair Distribution Function analysis and Small Angle X-ray Scattering. The infrastructure and software described here extend the existing capabilitiesmore » at XPD to accommodate radioactive materials. Such techniques will contribute crucial information to the characterization and quantification of advanced materials for nuclear energy applications. We describe the automated radioactive sample collection capabilities and recent X-ray Diffraction and Small Angle X-ray Scattering results from neutron irradiated reactor pressure vessel steels and oxide dispersion strengthened steels.« less

Infrastructure development for radioactive materials at the NSLS-II

DOE PAGES

Sprouster, David J.; Weidner, R.; Ghose, S. K.; ...

2017-11-04

The X-ray Powder Diffraction (XPD) Beamline at the National Synchrotron Light Source-II is a multipurpose instrument designed for high-resolution, high-energy X-ray scattering techniques. In this paper, the capabilities, opportunities and recent developments in the characterization of radioactive materials at XPD are described. The overarching goal of this work is to provide researchers access to advanced synchrotron techniques suited to the structural characterization of materials for advanced nuclear energy systems. XPD is a new beamline providing high photon flux for X-ray Diffraction, Pair Distribution Function analysis and Small Angle X-ray Scattering. The infrastructure and software described here extend the existing capabilitiesmore » at XPD to accommodate radioactive materials. Such techniques will contribute crucial information to the characterization and quantification of advanced materials for nuclear energy applications. Finally, we describe the automated radioactive sample collection capabilities and recent X-ray Diffraction and Small Angle X-ray Scattering results from neutron irradiated reactor pressure vessel steels and oxide dispersion strengthened steels.« less

Illicit drug detection using energy dispersive x-ray diffraction

NASA Astrophysics Data System (ADS)

Cook, E. J.; Griffiths, J. A.; Koutalonis, M.; Gent, C.; Pani, S.; Horrocks, J. A.; George, L.; Hardwick, S.; Speller, R.

2009-05-01

Illicit drugs are imported into countries in myriad ways, including via the postal system and courier services. An automated system is required to detect drugs in parcels for which X-ray diffraction is a suitable technique as it is non-destructive, material specific and uses X-rays of sufficiently high energy to penetrate parcels containing a range of attenuating materials. A database has been constructed containing the measured powder diffraction profiles of several thousand materials likely to be found in parcels. These include drugs, cutting agents, packaging and other innocuous materials. A software model has been developed using these data to predict the diffraction profiles which would be obtained by X-ray diffraction systems with a range of suggested detector (high purity germanium, CZT and scintillation), source and collimation options. The aim of the model was to identify the most promising system geometries, which was done with the aid of multivariate analysis (MVA). The most promising systems were constructed and tested. The diffraction profiles of a range of materials have been measured and used to both validate the model and to identify the presence of drugs in sample packages.

Wavefront aberrations of x-ray dynamical diffraction beams.

PubMed

Liao, Keliang; Hong, Youli; Sheng, Weifan

2014-10-01

The effects of dynamical diffraction in x-ray diffractive optics with large numerical aperture render the wavefront aberrations difficult to describe using the aberration polynomials, yet knowledge of them plays an important role in a vast variety of scientific problems ranging from optical testing to adaptive optics. Although the diffraction theory of optical aberrations was established decades ago, its application in the area of x-ray dynamical diffraction theory (DDT) is still lacking. Here, we conduct a theoretical study on the aberration properties of x-ray dynamical diffraction beams. By treating the modulus of the complex envelope as the amplitude weight function in the orthogonalization procedure, we generalize the nonrecursive matrix method for the determination of orthonormal aberration polynomials, wherein Zernike DDT and Legendre DDT polynomials are proposed. As an example, we investigate the aberration evolution inside a tilted multilayer Laue lens. The corresponding Legendre DDT polynomials are obtained numerically, which represent balanced aberrations yielding minimum variance of the classical aberrations of an anamorphic optical system. The balancing of classical aberrations and their standard deviations are discussed. We also present the Strehl ratio of the primary and secondary balanced aberrations.

Langmuir-Blodgett films of random copolymers of fluoroalkyl(meth)acrylate and methacrylic acid: Fabrication and X-ray diffraction study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Safronov, V.; Feigin, L.A.; Budovskaya, L.D.

1994-12-31

Langmuir-Blodgett films of amphiphilic fluorinated copolymers were fabricated and studied by X-ray diffraction. Although these films show poor interlayer periodicity, they possess a uniform thickness even in the case of very thin films of one bilayer (22 {angstrom}). This feature was used to obtain complex LB structures (superlattices) with alteration of copolymer and fatty acid bilayers. X-ray diffraction data proved the regular periodical organization of these structures and allowed to calculate electron density distribution across the superlattices.

Crystallization and preliminary X-ray diffraction study of the protealysin precursor belonging to the peptidase family M4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gromova, T. Yu., E-mail: duk@img.ras.ru; Demidyuk, I. V.; Kostrov, S. V.

2008-09-15

A protealysin precursor (the enzyme of the peptidase family M4) was crystallized for the first time. The crystal-growth conditions were found, and single crystals of the protein with dimensions of 0.3-0.5 mm were grown. The preliminary X-ray diffraction study of the enzyme was performed. The protealysin precursor was shown to crystallize in two crystal modifications suitable for the X-ray diffraction study of the three-dimensional structure of the protein molecule at atomic resolution.

Simulating Picosecond X-ray Diffraction from shocked crystals by Post-processing Molecular Dynamics Calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kimminau, G; Nagler, B; Higginbotham, A

2008-06-19

Calculations of the x-ray diffraction patterns from shocked crystals derived from the results of Non-Equilibrium-Molecular-Dynamics (NEMD) simulations are presented. The atomic coordinates predicted by the NEMD simulations combined with atomic form factors are used to generate a discrete distribution of electron density. A Fast-Fourier-Transform (FFT) of this distribution provides an image of the crystal in reciprocal space, which can be further processed to produce quantitative simulated data for direct comparison with experiments that employ picosecond x-ray diffraction from laser-irradiated crystalline targets.

Framework for three-dimensional coherent diffraction imaging by focused beam x-ray Bragg ptychography.

PubMed

Hruszkewycz, Stephan O; Holt, Martin V; Tripathi, Ash; Maser, Jörg; Fuoss, Paul H

2011-06-15

We present the framework for convergent beam Bragg ptychography, and, using simulations, we demonstrate that nanocrystals can be ptychographically reconstructed from highly convergent x-ray Bragg diffraction. The ptychographic iterative engine is extended to three dimensions and shown to successfully reconstruct a simulated nanocrystal using overlapping raster scans with a defocused curved beam, the diameter of which matches the crystal size. This object reconstruction strategy can serve as the basis for coherent diffraction imaging experiments at coherent scanning nanoprobe x-ray sources.

Three-dimensional imaging of nanoscale materials by using coherent x-rays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miao, Jianwei

X-ray crystallography is currently the primary methodology used to determine the 3D structure of materials and macromolecules. However, many nanostructures, disordered materials, biomaterials, hybrid materials and biological specimens are noncrystalline and, hence, their structures are not accessible by X-ray crystallography. Probing these structures therefore requires the employment of different approaches. A very promising technique currently under rapid development is X-ray diffraction microscopy (or lensless imaging), in which the coherent X-ray diffraction pattern of a noncrystalline specimen is measured and then directly phased to obtain a high-resolution image. Through the DOE support over the past three years, we have applied X-raymore » diffraction microscopy to quantitative imaging of GaN quantum dot particles, and revealed the internal GaN-Ga2O3 core shell structure in three dimensions. By exploiting the abrupt change in the scattering cross-section near electronic resonances, we carried out the first experimental demonstration of resonant X-ray diffraction microscopy for element specific imaging. We performed nondestructive and quantitative imaging of buried Bi structures inside a Si crystal by directly phasing coherent X-ray diffraction patterns acquired below and above the Bi M5 edge. We have also applied X-ray diffraction microscopy to nondestructive imaging of mineral crystals inside biological composite materials - intramuscular fish bone - at the nanometer scale resolution. We identified mineral crystals in collagen fibrils at different stages of mineralization and proposed a dynamic mechanism to account for the nucleation and growth of mineral crystals in the collagen matrix. In addition, we have also discovered a novel 3D imaging modality, denoted ankylography, which allows for complete 3D structure determination without the necessity of sample titling or scanning. We showed that when the diffraction pattern of a finite object is sampled at a sufficiently fine scale on the Ewald sphere, the 3D structure of the object is determined by the 2D spherical pattern. We confirmed the theoretical analysis by performing 3D numerical reconstructions of a sodium silicate glass structure at 2 A resolution from a 2D spherical diffraction pattern alone. As X-ray free electron lasers are under rapid development worldwide, ankylography may open up a new horizon to obtain the 3D structure of a non-crystalline specimen from a single pulse and allow time-resolved 3D structure determination of disordered materials.« less

Microfluidic Chips for In Situ Crystal X-ray Diffraction and In Situ Dynamic Light Scattering for Serial Crystallography.

PubMed

Gicquel, Yannig; Schubert, Robin; Kapis, Svetlana; Bourenkov, Gleb; Schneider, Thomas; Perbandt, Markus; Betzel, Christian; Chapman, Henry N; Heymann, Michael

2018-04-24

This protocol describes fabricating microfluidic devices with low X-ray background optimized for goniometer based fixed target serial crystallography. The devices are patterned from epoxy glue using soft lithography and are suitable for in situ X-ray diffraction experiments at room temperature. The sample wells are lidded on both sides with polymeric polyimide foil windows that allow diffraction data collection with low X-ray background. This fabrication method is undemanding and inexpensive. After the sourcing of a SU-8 master wafer, all fabrication can be completed outside of a cleanroom in a typical research lab environment. The chip design and fabrication protocol utilize capillary valving to microfluidically split an aqueous reaction into defined nanoliter sized droplets. This loading mechanism avoids the sample loss from channel dead-volume and can easily be performed manually without using pumps or other equipment for fluid actuation. We describe how isolated nanoliter sized drops of protein solution can be monitored in situ by dynamic light scattering to control protein crystal nucleation and growth. After suitable crystals are grown, complete X-ray diffraction datasets can be collected using goniometer based in situ fixed target serial X-ray crystallography at room temperature. The protocol provides custom scripts to process diffraction datasets using a suite of software tools to solve and refine the protein crystal structure. This approach avoids the artefacts possibly induced during cryo-preservation or manual crystal handling in conventional crystallography experiments. We present and compare three protein structures that were solved using small crystals with dimensions of approximately 10-20 µm grown in chip. By crystallizing and diffracting in situ, handling and hence mechanical disturbances of fragile crystals is minimized. The protocol details how to fabricate a custom X-ray transparent microfluidic chip suitable for in situ serial crystallography. As almost every crystal can be used for diffraction data collection, these microfluidic chips are a very efficient crystal delivery method.

Characterization of X-Ray Diffraction System with a Microfocus X-Ray Source and a Polycapillary Optic

NASA Technical Reports Server (NTRS)

Gubarev, Mikhail; Marshall, Joy K.; Ciszak, Ewa; Ponomarev, Igor

2000-01-01

We present here an optimized microfocus x-ray source and polycapillary optic system designed for diffraction of small protein crystals. The x-ray beam is formed by a 5.5mm focal length capillary collimator coupled with a 40 micron x-ray source operating at 46Watts. Measurements of the x-ray flux, the divergence and the spectral characteristics of the beam are presented, This optimized system provides a seven fold greater flux than our recently reported configuration [M. Gubarev, et al., J. of Applied Crystallography (2000) 33, in press]. We now make a comparison with a 5kWatts rotating anode generator (Rigaku) coupled with confocal multilayer focusing mirrors (Osmic, CMF12- 38Cu6). The microfocus x-ray source and polycapillary collimator system delivers 60% of the x-ray flux from the rotating anode system. Additional ways to improve our microfocus x-ray system, and thus increase the x-ray flux will be discussed.

Specimen preparation for cryogenic coherent X-ray diffraction imaging of biological cells and cellular organelles by using the X-ray free-electron laser at SACLA

PubMed Central

Kobayashi, Amane; Sekiguchi, Yuki; Oroguchi, Tomotaka; Okajima, Koji; Fukuda, Asahi; Oide, Mao; Yamamoto, Masaki; Nakasako, Masayoshi

2016-01-01

Coherent X-ray diffraction imaging (CXDI) allows internal structures of biological cells and cellular organelles to be analyzed. CXDI experiments have been conducted at 66 K for frozen-hydrated biological specimens at the SPring-8 Angstrom Compact Free-Electron Laser facility (SACLA). In these cryogenic CXDI experiments using X-ray free-electron laser (XFEL) pulses, specimen particles dispersed on thin membranes of specimen disks are transferred into the vacuum chamber of a diffraction apparatus. Because focused single XFEL pulses destroy specimen particles at the atomic level, diffraction patterns are collected through raster scanning the specimen disks to provide fresh specimen particles in the irradiation area. The efficiency of diffraction data collection in cryogenic experiments depends on the quality of the prepared specimens. Here, detailed procedures for preparing frozen-hydrated biological specimens, particularly thin membranes and devices developed in our laboratory, are reported. In addition, the quality of the frozen-hydrated specimens are evaluated by analyzing the characteristics of the collected diffraction patterns. Based on the experimental results, the internal structures of the frozen-hydrated specimens and the future development for efficient diffraction data collection are discussed. PMID:27359147

Specimen preparation for cryogenic coherent X-ray diffraction imaging of biological cells and cellular organelles by using the X-ray free-electron laser at SACLA.

PubMed

Kobayashi, Amane; Sekiguchi, Yuki; Oroguchi, Tomotaka; Okajima, Koji; Fukuda, Asahi; Oide, Mao; Yamamoto, Masaki; Nakasako, Masayoshi

2016-07-01

Coherent X-ray diffraction imaging (CXDI) allows internal structures of biological cells and cellular organelles to be analyzed. CXDI experiments have been conducted at 66 K for frozen-hydrated biological specimens at the SPring-8 Angstrom Compact Free-Electron Laser facility (SACLA). In these cryogenic CXDI experiments using X-ray free-electron laser (XFEL) pulses, specimen particles dispersed on thin membranes of specimen disks are transferred into the vacuum chamber of a diffraction apparatus. Because focused single XFEL pulses destroy specimen particles at the atomic level, diffraction patterns are collected through raster scanning the specimen disks to provide fresh specimen particles in the irradiation area. The efficiency of diffraction data collection in cryogenic experiments depends on the quality of the prepared specimens. Here, detailed procedures for preparing frozen-hydrated biological specimens, particularly thin membranes and devices developed in our laboratory, are reported. In addition, the quality of the frozen-hydrated specimens are evaluated by analyzing the characteristics of the collected diffraction patterns. Based on the experimental results, the internal structures of the frozen-hydrated specimens and the future development for efficient diffraction data collection are discussed.

Emerging opportunities in structural biology with X-ray free-electron lasers

PubMed Central

Schlichting, Ilme; Miao, Jianwei

2012-01-01

X-ray free-electron lasers (X-FELs) produce X-ray pulses with extremely brilliant peak intensity and ultrashort pulse duration. It has been proposed that radiation damage can be “outrun” by using an ultra intense and short X-FEL pulse that passes a biological sample before the onset of significant radiation damage. The concept of “diffraction-before-destruction” has been demonstrated recently at the Linac Coherent Light Source, the first operational hard X-ray FEL, for protein nanocrystals and giant virus particles. The continuous diffraction patterns from single particles allow solving the classical “phase problem” by the oversampling method with iterative algorithms. If enough data are collected from many identical copies of a (biological) particle, its three-dimensional structure can be reconstructed. We review the current status and future prospects of serial femtosecond crystallography (SFX) and single-particle coherent diffraction imaging (CDI) with X-FELs. PMID:22922042

Publications - GMC 58 | Alaska Division of Geological & Geophysical Surveys

Science.gov Websites

DGGS GMC 58 Publication Details Title: X-ray diffraction and scanning electron microscopy mineral , Michael, and Core Laboratories, 1985, X-ray diffraction and scanning electron microscopy mineral analyses

Observation of divergent-beam X-ray diffraction from a crystal of diamond using synchrotron radiation.

PubMed

Glazer, A M; Collins, S P; Zekria, D; Liu, J; Golshan, M

2004-03-01

In 1947 Kathleen Lonsdale conducted a series of experiments on X-ray diffraction using a divergent beam external to a crystal sample. Unlike the Kossel technique, where divergent X-rays are excited by the presence of fluorescing atoms within the crystal, the use of an external divergent source made it possible to study non-fluorescing crystals. The resulting photographs not only illustrated the complexity of X-ray diffraction from crystals in a truly beautiful way, but also demonstrated unprecedented experimental precision. This long-forgotten work is repeated here using a synchrotron radiation source and, once again, considerable merit is found in Lonsdale's technique. The results of this experiment suggest that, through the use of modern 'third-generation' synchrotron sources, divergent-beam diffraction could soon enjoy a renaissance for high-precision lattice-parameter determination and the study of crystal perfection.

Soft X-ray spectromicroscopy using ptychography with randomly phased illumination

NASA Astrophysics Data System (ADS)

Maiden, A. M.; Morrison, G. R.; Kaulich, B.; Gianoncelli, A.; Rodenburg, J. M.

2013-04-01

Ptychography is a form of scanning diffractive imaging that can successfully retrieve the modulus and phase of both the sample transmission function and the illuminating probe. An experimental difficulty commonly encountered in diffractive imaging is the large dynamic range of the diffraction data. Here we report a novel ptychographic experiment using a randomly phased X-ray probe to considerably reduce the dynamic range of the recorded diffraction patterns. Images can be reconstructed reliably and robustly from this setup, even when scatter from the specimen is weak. A series of ptychographic reconstructions at X-ray energies around the L absorption edge of iron demonstrates the advantages of this method for soft X-ray spectromicroscopy, which can readily provide chemical sensitivity without the need for optical refocusing. In particular, the phase signal is in perfect registration with the modulus signal and provides complementary information that can be more sensitive to changes in the local chemical environment.

Thermal analysis, X-ray powder diffraction and electron microscopy data related with the production of 1:1 Caffeine:Glutaric Acid cocrystals.

PubMed

Duarte, Íris; Andrade, Rita; Pinto, João F; Temtem, Márcio

2016-09-01

The data presented in this article are related to the production of 1:1 Caffeine:Glutaric Acid cocrystals as part of the research article entitled "Green production of cocrystals using a new solvent-free approach by spray congealing" (Duarte et al., 2016) [1]. More specifically, here we present the thermal analysis and the X-ray powder diffraction data for pure Glutaric Acid, used as a raw material in [1]. We also include the X-ray powder diffraction and electron microscopy data obtained for the 1:1 Caffeine:Glutaric Acid cocrystal (form II) produced using the cooling crystallization method reported in "Operating Regions in Cooling Cocrystallization of Caffeine and Glutaric Acid in Acetonitrile" (Yu et al., 2010) [2]. Lastly, we show the X-ray powder diffraction data obtained for assessing the purity of the 1:1 Caffeine:Glutaric cocrystals produced in [1].

Submicron x-ray diffraction and its applications to problems in materials and environmental science

NASA Astrophysics Data System (ADS)

Tamura, N.; Celestre, R. S.; MacDowell, A. A.; Padmore, H. A.; Spolenak, R.; Valek, B. C.; Meier Chang, N.; Manceau, A.; Patel, J. R.

2002-03-01

The availability of high brilliance third generation synchrotron sources together with progress in achromatic focusing optics allows us to add submicron spatial resolution to the conventional century-old x-ray diffraction technique. The new capabilities include the possibility to map in situ, grain orientations, crystalline phase distribution, and full strain/stress tensors at a very local level, by combining white and monochromatic x-ray microbeam diffraction. This is particularly relevant for high technology industry where the understanding of material properties at a microstructural level becomes increasingly important. After describing the latest advances in the submicron x-ray diffraction techniques at the Advanced Light Source, we will give some examples of its application in material science for the measurement of strain/stress in metallic thin films and interconnects. Its use in the field of environmental science will also be discussed.

Ultrahigh vacuum/high pressure chamber for surface x-ray diffraction experiments

NASA Astrophysics Data System (ADS)

Bernard, P.; Peters, K.; Alvarez, J.; Ferrer, S.

1999-02-01

We describe an ultrahigh vacuum chamber that can be internally pressurized to several bars and that is designed to perform surface x-ray diffraction experiments on solid-gas interfaces. The chamber has a cylindrical beryllium window that serves as the entrance and exit for the x rays. The sample surface can be ion bombarded with an ancillary ion gun and annealed to 1200 K.