Single Crystal X-Ray Diffraction in Structure Elucidation of Arborinine from Glycosmis pentaphylla

2017 ◽  
Vol 7 (3) ◽  
Author(s):  
Moon Moon Das ◽  
Dibakar Chandra Deka ◽  
Ranjit Thakuria
Keyword(s):  
Single Crystal ◽  
Structure Elucidation ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Difficulties to Determine the Absolute Configuration of Guaiaretic Acid

2018 ◽  
Vol 13 (8) ◽  
pp. 1934578X1801300
Author(s):  
Alfredo R. Ortega ◽  
Eleuterio Burgueño-Tapia ◽  
Pedro Joseph-Nathan
Keyword(s):  
Symmetric Space ◽  
Single Crystal ◽  
Absolute Configuration ◽  
Structure Elucidation ◽  
Carbon Chain ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
The Absolute ◽  
Stereogenic Center

An account of the difficulties to determine the absolute configuration (AC) of guaiaretic acid (1a), using contemporary methodology, is described in commemoration of the century of its structure elucidation. In fact, the herein studied molecule was the derived diacetate 1b, since the natural lignan slowly decomposes upon manipulation. Single crystal X-ray diffraction of 1b demonstrated the structure, but calculation of Flack and Hooft parameters to know the AC was unsuccessful since the crystals were triclinic, P-1, which is a centro-symmetric space group. In turn, manual band to band comparison of experimental and DFT B3LYP/DGDZVP calculated VCD spectra of 1b allowed ascertaining its AC, although automatic comparison using the Compare VOA software was not very successful. This behavior is associated to the fact that the studied molecule has a sole stereogenic center located on the acyclic portion of a carbon chain possessing two quite similar substituents. The behavior is discussed in relation to cases where the molecular flexibility also generates a very large number of conformers.

scholarly journals Synthesis and Structure Elucidation of N′-(4-Methoxybenzylidene)-5-methyl-1-phenyl-1H-1,2,3-triazole-4-carbohydrazide

Molbank ◽  
10.3390/m1034 ◽  
2018 ◽  
Vol 2018 (4) ◽  
pp. M1034 ◽  
Author(s):  
Mohammad Alotaibi ◽  
Hanan Mohamed ◽  
Bakr Abdel-Wahab ◽  
Amany Hegazy ◽  
Benson Kariuki ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Single Crystal ◽  
Mass Spectroscopy ◽  
Structure Elucidation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acid Catalyzed ◽  
Nuclear Magnetic

N′-(4-Methoxybenzylidene)-5-methyl-1-phenyl-1H-1,2,3-triazole-4-carbohydrazide (3) was synthesized in a yield of 88% from an acid-catalyzed reaction of 5-methyl-1-phenyl-1H-1,2,3- triazole-4-carbohydrazide and 4-methoxybenzaldehyde in ethanol under reflux for 2.5 h. The structure of 3 was confirmed by the data obtained from infrared, nuclear magnetic resonance, mass spectroscopy, single crystal X-ray diffraction, and microanalysis.

Electron Microscopy of Shock Loaded Polycrystalline Beryllium

1974 ◽  
Vol 32 ◽  
pp. 506-507 ◽  
Author(s):  
J. M. Galbraith ◽  
L. E. Murr ◽  
A. L. Stevens
Keyword(s):  
Electron Microscopy ◽  
Wave Propagation ◽  
Structural Change ◽  
Single Crystal ◽  
Diffraction Pattern ◽  
Shock Loading ◽  
Slip Systems ◽  
Compression Tests ◽  
X Ray Diffraction ◽  
X Ray

Uniaxial compression tests and hydrostatic tests at pressures up to 27 kbars have been performed to determine operating slip systems in single crystal and polycrystal1ine beryllium. A recent study has been made of wave propagation in single crystal beryllium by shock loading to selectively activate various slip systems, and this has been followed by a study of wave propagation and spallation in textured, polycrystal1ine beryllium. An alteration in the X-ray diffraction pattern has been noted after shock loading, but this alteration has not yet been correlated with any structural change occurring during shock loading of polycrystal1ine beryllium.This study is being conducted in an effort to characterize the effects of shock loading on textured, polycrystal1ine beryllium. Samples were fabricated from a billet of Kawecki-Berylco hot pressed HP-10 beryllium.

Crystal structure of an inclusion complex between chiral monoaza-15-crown-5 and S(–)-1-phenyl-ethyl ammonium percholorate

2003 ◽  
Vol 218 (5) ◽  
Author(s):  
Süheyla Özbey ◽  
F. B. Kaynak ◽  
M. Toğrul ◽  
N. Demirel ◽  
H. Hoşgören
Keyword(s):  
Crystal Structure ◽  
Inclusion Complex ◽  
Single Crystal ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
New Type

AbstractA new type of inclusion complex, S(–)-1 phenyl ethyl ammonium percholorate complex of R-(–)-2-ethyl - N - benzyl - 4, 7, 10, 13 - tetraoxa -1- azacyclopentadecane, has been prepared and studied by NMR, IR and single crystal X-ray diffraction techniques. The compound crystallizes in space group

Unusual Rearrangement of Naphthalene in the Synthesis of a Novel B8-B8-Bridged Derivative in the [(1,2-C2B9H11)2-3-Co]- Series. X-Ray Structure and 11B NMR Spectra of [8,8'-μ-(CH2-C9H6)-(1,2-C2B9H10)2-3-Co]- (CH3)4N+

1997 ◽  
Vol 62 (5) ◽  
pp. 746-751 ◽  
Author(s):  
Andreas Franken ◽  
Jaromír Plešek ◽  
Christiane Nachtigal
Keyword(s):  
Nmr Spectroscopy ◽  
Single Crystal ◽  
Nucleophilic Substitution ◽  
Nmr Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Unusual Rearrangement ◽  
Multinuclear Nmr Spectroscopy ◽  
11B Nmr ◽  
Isolated Compound

On treatment of the [(1,2-C2B9H11)2Co]- ion with naphthalene in presence of AlCl3 a remarkably bridged [8,8'-μ-(CH2-C9H6)-(1,2-C2B9H10)2-3-Co]- ion is obtained as a single isolated compound. The triatomic -CH2-C9H6- bridge is derived from the rearranged naphthalene nucleus. The mechanism of this reaction is obscure but it does resemble the "Electrophile-Induced Nucleophilic Substitution" reported earlier. The structure of the compound was established by multinuclear NMR spectroscopy and by single crystal X-ray diffraction.

scholarly journals An investigation of polyhedral deformation in two mixed-metal diarsenates: SrZnAs2O7and BaCuAs2O7

2015 ◽  
Vol 71 (4) ◽  
pp. 330-337 ◽  
Author(s):  
Sabina Kovač ◽  
Ljiljana Karanović ◽  
Tamara Đorđević
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
General Formula ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Open Framework ◽  
Geometrical Characteristics ◽  
Barium Copper

Two isostructural diarsenates, SrZnAs2O7(strontium zinc diarsenate), (I), and BaCuAs2O7[barium copper(II) diarsenate], (II), have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. The three-dimensional open-framework crystal structure consists of corner-sharingM2O5(M2 = Zn or Cu) square pyramids and diarsenate (As2O7) groups. Each As2O7group shares its five corners with five differentM2O5square pyramids. The resulting framework delimits two types of tunnels aligned parallel to the [010] and [100] directions where the large divalent nine-coordinatedM1 (M1 = Sr or Ba) cations are located. The geometrical characteristics of theM1O9,M2O5and As2O7groups of known isostructural diarsenates, adopting the general formulaM1IIM2IIAs2O7(M1II= Sr, Ba, Pb;M2II= Mg, Co, Cu, Zn) and crystallizing in the space groupP21/n, are presented and discussed.

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