Nitrogen inversion in the solid state: characterization of a conformational process in crystalline 1,3,5-tribenzyl-1,3,5-triazacyclohexane by X-ray analysis at several temperatures

Author(s):  
George A. Sim
2010 ◽  
Vol 99 (9) ◽  
pp. 3684-3697 ◽  
Author(s):  
Faraj Atassi ◽  
Chen Mao ◽  
Ahmad S. Masadeh ◽  
Stephen R. Byrn

2002 ◽  
Vol 80 (8) ◽  
pp. 1162-1165 ◽  
Author(s):  
B Henrissat ◽  
G K Hamer ◽  
M G Taylor ◽  
R H Marchessault

A series of dodecyl 1-thio-β-D-glycosides has been synthesized and characterized (DSC, NMR, CP MAS, X-ray diffraction) as possible new marking materials with liquid-crystalline properties. These compounds undergo solid to liquid crystal phase transitions at various temperatures, which depend on the nature of the carbohydrate part of the structure. Their liquid-crystalline phases show extreme shear thinning behaviour.Key words: liquid crystal, powder X-ray diffraction, phase transition, thioglycoside, solid-state NMR, marking material


2006 ◽  
Vol 21 (3) ◽  
pp. 214-219 ◽  
Author(s):  
Abderrahim Aatiq ◽  
Btissame Haggouch ◽  
Rachid Bakri ◽  
Youssef Lakhdar ◽  
Ismael Saadoune

Structures of two K2SnX(PO4)3(X=Fe,Yb) phosphates, obtained by conventional solid state reaction techniques at 950 °C, were determined at room temperature by X-ray powder diffraction using Rietveld analysis. The two materials exhibit the langbeinite-type structure (P213 space group, Z=4). Cubic unit cell parameter values are: a=9.9217(4) Å and a=10.1583(4) Å for K2SnFe(PO4)3 and K2SnYb(PO4)3, respectively. Structural refinements show that the two crystallographically independent octahedral sites (of symmetry 3) have a mixed Sn∕X (X=Fe,Yb) population although ordering is stronger in the Yb phase than in the Fe phase.


Steroids ◽  
2011 ◽  
Vol 76 (3) ◽  
pp. 261-268 ◽  
Author(s):  
Kari V. Ahonen ◽  
Manu K. Lahtinen ◽  
Arto M. Valkonen ◽  
Martin Dračínský ◽  
Erkki T. Kolehmainen

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