scholarly journals Structural properties of methoxy derivatives of benzyl bromide, determined from powder X-ray diffraction data

2005 ◽  
Vol 20 (4) ◽  
pp. 345-352 ◽  
Author(s):  
Zhigang Pan ◽  
Eugene Y. Cheung ◽  
Kenneth D. M. Harris ◽  
Edwin C. Constable ◽  
Catherine E. Housecroft
Keyword(s):  
Structural Properties ◽  
Diffraction Data ◽  
Benzyl Bromide ◽  
Building Blocks ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Solution ◽  
Derivatives Of ◽  
Potential Use

Structure determination of 3,5-dimethoxybenzyl bromide and 3,4,5-trimethoxybenzyl bromide has been carried out from laboratory powder X-ray diffraction data using the direct-space Genetic Algorithm technique for structure solution followed by Rietveld refinement. These two compounds are of interest for their potential use as building blocks for the synthesis of dendritic materials. Although the two molecules differ only in the presence/absence of the methoxy group at the 4-position of the aromatic ring, the structural properties of the two materials are significantly different.

scholarly journals Crystallization and X-ray diffraction data analysis of human deoxyhaemoglobin A0 fully stripped of any anions

1999 ◽  
Vol 55 (11) ◽  
pp. 1914-1916 ◽  
Author(s):  
F. A. V. Seixas ◽  
W. F. de Azevedo ◽  
M. F. Colombo
Keyword(s):  
Diffraction Data ◽  
Oxygen Affinity ◽  
X Ray Diffraction ◽  
Structural Explanation ◽  
Human Haemoglobin ◽  
X Ray ◽  
High Resolution Structure ◽  
Allosteric Properties

In this work, initial crystallographic studies of human haemoglobin (Hb) crystallized in isoionic and oxygen-free PEG solution are presented. Under these conditions, functional measurements of the O2-linked binding of water molecules and release of protons have evidenced that Hb assumes an unforeseen new allosteric conformation. The determination of the high-resolution structure of the crystal of human deoxy-Hb fully stripped of anions may provide a structural explanation for the role of anions in the allosteric properties of Hb and, particularly, for the influence of chloride on the Bohr effect, the mechanism by which Hb oxygen affinity is regulated by pH. X-ray diffraction data were collected to 1.87 Å resolution using a synchrotron-radiation source. Crystals belong to the space group P21212 and preliminary analysis revealed the presence of one tetramer in the asymmetric unit. The structure is currently being refined using maximum-likelihood protocols.

scholarly journals CRYSTAL STRUCTURE OF BIS[1-(DIAMINOMETHYLENE)-THIOURON-1-IUM] SULFATE

2017 ◽  
Vol 60 (1) ◽  
pp. 45
Author(s):  
Yuliya V. Butina ◽  
Elena A. Danilova ◽  
Maxim V. Dmitriev ◽  
Aleksey V. Solomonov
Keyword(s):  
Crystal Structure ◽  
Ir Spectroscopy ◽  
Diffraction Data ◽  
Crystalline State ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tautomeric Forms ◽  
Structural Database ◽  
Derivatives Of

For citation:Butina Yu.V., Danilova E.A., Dmitriev M.V., Solomonov А.V. Crystal structure of bis[1-(diaminomethylene)-thiouron-1-ium] sulfate. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 1. P. 45-49. In this work crystal data of bis[1-(diaminomethylene)-thiouron-1-ium] sulfate is shown. This compound was characterized by IR spectroscopy and elemental analysis. The monocrystal of this compound was obtained and the structure was confirmed by single X-ray analysis. Moreover, the work describes potential application of synthesized compound. Comparative characteristics of thiourea and its known salts are demonstrated. It is known, that derivatives of thiourea have several tautomeric forms, which can be different in crystalline state or in solution. Therefore, changed scheme of the synthesis of 2-imino-4-thiobiuret is proposed. Elemental cell of crystal consists of two 1-(diaminomethylene)thiouron-1-ium cations and one sulfat anion. A full set of X-ray diffraction data was deposited in the Cambridge Structural Database (deposit CCDC 1421710) and it can be gotten from the site www.ccdc.cam.ac.uk/data_request/cif.

scholarly journals Rubidium tetrafluoridobromate(III): redetermination of the crystal structure from single-crystal X-ray diffraction data

IUCrData ◽  
2019 ◽  
Vol 4 (11) ◽  
Author(s):  
Artem V. Malin ◽  
Sergei I. Ivlev ◽  
Roman V. Ostvald ◽  
Florian Kraus
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Single Crystals ◽  
Diffraction Data ◽  
Structure Type ◽  
X Ray Diffraction ◽  
X Ray ◽  
Square Planar ◽  
Atomic Coordinates

Single crystals of rubidium tetrafluoridobromate(III), RbBrF4, were grown by melting and recrystallizing RbBrF4 from its melt. This is the first determination of the crystal structure of RbBrF4 using single-crystal X-ray diffraction data. We confirmed that the structure contains square-planar [BrF4]− anions and rubidium cations that are coordinated by F atoms in a square-antiprismatic manner. The compound crystallizes in the KBrF4 structure type. Atomic coordinates and bond lengths and angles were determined with higher precision than in a previous report based on powder X-ray diffraction data [Ivlev et al. (2015). Z. Anorg. Allg. Chem. 641, 2593–2598].

scholarly journals NMR and X-ray studies of apetalic acid isolated from Calophyllum brasiliense and of its chiral amides

2021 ◽  
Author(s):  
Marie-Rose Van Calsteren ◽  
Ricardo Reyes-Chilpa ◽  
Chistopher K Jankowski ◽  
Fleur Gagnon ◽  
Simón Hernández-Ortega ◽  
...  
Keyword(s):  
Antimycobacterial Activity ◽  
Side Chain ◽  
Carboxyl Group ◽  
X Ray Diffraction ◽  
Rain Forests ◽  
X Ray ◽  
X Ray Crystallography ◽  
Calophyllum Brasiliense ◽  
Derivatives Of

The tropical tree Calophyllum brasiliense (Clusiaceae) grows in the rain forests from Brazil to Mexico. Its leaves, as well as those of other Calophyllum species, are rich sources of chromanone acids, such as apetalic acid, isoapetalic acid, and their derivatives. Apetalic acid has shown significant antimycobacterial activity. The biological activity of apetalic acid has been related to the configuration of three asymmetric centers and the stereochemistry of the molecule; however, the C-19 configuration in the acidic side chain has not been fully resolved. For this reason, the unequivocal determination of the absolute configuration by means of X-ray crystallography in a sample of unique homogeneous apetalic acid stereoisomer was the most important point to start this study. We prepared some chiral amides using the carboxyl group. We determined the C-19 stereochemistry of apetalic acid, and its specific chiral derivatives, using NMR, X-ray diffraction methods, and molecular mechanics. Finally, we observed that steric hindrance in the side chain of apetalic acid leads to restriction of rotation around the pivotal link C-10 and C-19 establishing chiral centers at C2(R), C3(S), and C19(R). We were able to separate derivatives of these two high-rotatory-barrier conformers of apetalic acid by forming diastereoisomeric amides with phenylglycine methyl ester having a chiral center at C-2’. Our results allowed the conclusion of the existence of atropisomerism in the apetalic acid molecule.

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