Preparation, single-crystal X-ray diffraction and high-resolution NMR spectroscopic analyses of N-[(1,4-anhydro-5-deoxy-2,3-O-isopropylidene-d,l-ribitol)-5-yl]trimethylammonium iodide

ABSTRACTFor nitride based devices such as LEDs, high power FETs and laser diodes, single crystal substrates of AlN are highly desirable. While the sublimation technique is suitable for growing bulk AlN crystals, appropriate seeds are also necessary for growing large diameter oriented boules. 4H- and 6H-SiC substrates which are readily available commercially can potentially be implemented as seeds for bulk AlN growth. However, issues regarding SiC decomposition at high temperatures, thermal expansion mismatch, single crystal growth, etc. need to be addressed. Towards this end, a series of growth experiments have been carried out in a resistively heated reactor using on and off-axis 4H- and 6H-SiC substrates as seeds for AlN growth from the vapor phase. Several hundred microns thick AlN layers have been grown under different growth conditions. Synchrotron white beam x-ray topography (SWBXT) has been used to map the defect distribution in the grown layers and high resolution triple axis x-ray diffraction (HRTXD) experiments were carried out to record reciprocal space maps from which tilt, mismatch and strain data can be obtained. These results are analyzed with respect to the growth conditions in order to gain a better understanding of this growth process.

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Structural analysis of 6-S-(benzoxazol-2-yl)-6-deoxy1,2:3,4-di-O-isopropylidene-6-thio-α-d-galactopyranose by means of X-ray diffraction, high resolution NMR spectroscopy, and molecular modelling

Carbohydrate Research ◽

10.1016/0008-6215(96)00144-9 ◽

1996 ◽

Vol 290 (2) ◽

pp. 125-136 ◽

Cited By ~ 2

Author(s):

Miles T. Lakin ◽

Nadine Mouhous-Riou ◽

Christelle Lorin ◽

Patrick Rollin ◽

Jan Kroon ◽

...

Keyword(s):

Nmr Spectroscopy ◽

Structural Analysis ◽

High Resolution ◽

Molecular Modelling ◽

X Ray Diffraction ◽

X Ray ◽

High Resolution Nmr

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Purification, characterization, crystal structure and NO production inhibitory activity of three new sesquiterpenoids from homalomena occulta

Acta Crystallographica Section C Structural Chemistry ◽

10.1107/s2053229618013815 ◽

2018 ◽

Vol 74 (11) ◽

pp. 1440-1446

Author(s):

Qi Zhang ◽

Li Ma ◽

Zhaoxia Qu ◽

Guige Hou ◽

Yanan Wang ◽

...

Keyword(s):

Crystal Structure ◽

Single Crystal ◽

2D Nmr ◽

Inhibitory Effect ◽

Raw 264.7 Cells ◽

No Production ◽

Raw 264.7 ◽

X Ray Diffraction ◽

X Ray ◽

Spectroscopic Analyses

Two new isodaucane-type sesquiterpenoids, namely (1R,4S,5S,6R,7S,10R)-isodauc-6,7,10-triol, C15H28O3, (1), and (1R,4S,5S,6S,7S,10R)-isodauc-6,7,10-triol, (2), and a new eudesmane-type sesquiterpenoid, 1β,4β,5α-trihydroxyeudesmane, (3), were obtained from the rhizomes of homalomena occulta with the aid of column chromatography. Their structures were elucidated based on extensive spectroscopic analyses, including 1D NMR, 2D NMR and HRESIMS. The structure of (1) was confirmed by single-crystal X-ray diffraction and the absolute configuration was assigned with respect to that of the precursor. The single-crystal structure reveals that adjacent molecules of (1) embrace through two groups of intermolecular O—H...O hydrogen bonds to generate a two-dimensional sheet with a 63-net topology. The three compounds were evaluated for their activity against lipopolysaccharide-induced production of nitrogen oxide (NO) in RAW 264.7 cells, and (1) showed an inhibitory effect on NO production, with IC50 values of 5.7±0.22 µM.

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ChemInform Abstract: X-Ray Diffraction and High Resolution NMR Analysis of Methyl D-Glucopyranuronate Derivatives.

ChemInform ◽

10.1002/chin.200106177 ◽

2001 ◽

Vol 32 (6) ◽

pp. no-no

Author(s):

Anna Trynda ◽

Janusz Madaj ◽

Antoni Konitz ◽

Andrzej Wisniewski

Keyword(s):

High Resolution ◽

Nmr Analysis ◽

X Ray Diffraction ◽

X Ray ◽

High Resolution Nmr

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Scatterless hybrid metal–single-crystal slit for small-angle X-ray scattering and high-resolution X-ray diffraction

Journal of Applied Crystallography ◽

10.1107/s0021889808031129 ◽

2008 ◽

Vol 41 (6) ◽

pp. 1134-1139 ◽

Cited By ~ 98

Author(s):

Youli Li ◽

Roy Beck ◽

Tuo Huang ◽

Myung Chul Choi ◽

Morito Divinagracia

Keyword(s):

High Resolution ◽

Single Crystal ◽

Small Angle ◽

Incident Beam ◽

Single Crystal Substrate ◽

X Ray Diffraction ◽

Metal Base ◽

X Ray ◽

X Ray Scattering ◽

Ray Scattering

A simple hybrid design has been developed to produce practically scatterless aperture slits for small-angle X-ray scattering and high-resolution X-ray diffraction. The hybrid slit consists of a rectangular single-crystal substrate (e.g.Si or Ge) bonded to a high-density metal base with a large taper angle (> 10°). The beam-defining single-crystal tip is oriented far from any Bragg peak position with respect to the incident beam and hence produces none of the slit scattering commonly associated with conventional metal slits. It has been demonstrated that the incorporation of the scatterless slits leads to a much simplified design in small-angle X-ray scattering instruments employing only one or two apertures, with dramatically increased intensity (a threefold increase observed in the test setup) and improved low-angle resolution.

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Photoreversible interconversion of a phytochrome photosensory module in the crystalline state

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1912041116 ◽

2019 ◽

Vol 117 (1) ◽

pp. 300-307 ◽

Cited By ~ 4

Author(s):

E. Sethe Burgie ◽

Jonathan A. Clinger ◽

Mitchell D. Miller ◽

Aaron S. Brewster ◽

Pierre Aller ◽

...

Keyword(s):

Single Crystal ◽

Blue Light ◽

Green Light ◽

Crystallographic Structure ◽

X Ray Diffraction ◽

Major Barrier ◽

X Ray ◽

Spectroscopic Analyses ◽

Serial Femtosecond Crystallography

A major barrier to defining the structural intermediates that arise during the reversible photointerconversion of phytochromes between their biologically inactive and active states has been the lack of crystals that faithfully undergo this transition within the crystal lattice. Here, we describe a crystalline form of the cyclic GMP phosphodiesterases/adenylyl cyclase/FhlA (GAF) domain from the cyanobacteriochrome PixJ inThermosynechococcus elongatusassembled with phycocyanobilin that permits reversible photoconversion between the blue light-absorbing Pb and green light-absorbing Pg states, as well as thermal reversion of Pg back to Pb. The X-ray crystallographic structure of Pb matches previous models, including autocatalytic conversion of phycocyanobilin to phycoviolobilin upon binding and its tandem thioether linkage to the GAF domain. Cryocrystallography at 150 K, which compared diffraction data from a single crystal as Pb or after irradiation with blue light, detected photoconversion product(s) based on Fobs− Fobsdifference maps that were consistent with rotation of the bonds connecting pyrrole rings C and D. Further spectroscopic analyses showed that phycoviolobilin is susceptible to X-ray radiation damage, especially as Pg, during single-crystal X-ray diffraction analyses, which could complicate fine mapping of the various intermediate states. Fortunately, we found that PixJ crystals are amenable to serial femtosecond crystallography (SFX) analyses using X-ray free-electron lasers (XFELs). As proof of principle, we solved by room temperature SFX the GAF domain structure of Pb to 1.55-Å resolution, which was strongly congruent with synchrotron-based models. Analysis of these crystals by SFX should now enable structural characterization of the early events that drive phytochrome photoconversion.

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