Kinetically induced intermolecular association: unusual enthalpy changes in the nematic phase of a novel dimeric liquid-crystalline moleculeElectronic supplementary information (ESI) available: photomicrographs of the nematic phase formed by BOPPHB on cooling, X-ray diffraction patterns and DSC thermograms. See http://www.rsc.org/suppdata/cc/b2/b204901p/

2002 ◽  
pp. 2060-2061 ◽  
Author(s):  
Atsushi Yoshizawa ◽  
Akihisa Yamaguchi
Keyword(s):  
Nematic Phase ◽  
Liquid Crystalline ◽  
Supplementary Information ◽  
X Ray Diffraction ◽  
X Ray ◽  
Enthalpy Changes ◽  
Intermolecular Association ◽  
Diffraction Patterns ◽  
Dsc Thermograms

Study of the Liquid Crystalline Phases in Some Compounds of 4-Trans-(4-Alkyl)Cyclo-Hexylphenyl-Alkylcarboxylate

1983 ◽  
Vol 38 (12) ◽  
pp. 1362-1364 ◽  
Author(s):  
I. H. Ibrahim ◽  
W. Haase
Keyword(s):  
Differential Scanning Calorimetry ◽  
Nematic Phase ◽  
Liquid Crystalline ◽  
Intermolecular Distance ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Enthalpy Changes ◽  
Liquid Crystalline Phases ◽  
Nematic Phases

Abstract Three mesogenic compounds of the general formula have been investigated by differential scanning calorimetry. thermal optical microscopy and X-ray diffraction methods/Enthalpy changes of The different phase transitions for these compounds have been determined. H33 exhibits smectic B and nematic phases, whereas H34 and H75 exhibit only smectic B phases. The thickness of the smectic layers and the average intermolecular distance have been evaluated, as well as the corresponding molecular parameters in the nematic phase.

X-ray Diffraction Patterns of Liquid Crystalline Solutions of Poly-γ-benzyl-L-glutamate

Nature ◽  
1965 ◽  
Vol 206 (4984) ◽  
pp. 616-617 ◽  
Author(s):  
D. A. D. PARRY ◽  
A. ELLIOTT
Keyword(s):  
Liquid Crystalline ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns

scholarly journals Synthesis and physical properties of ferrocene derivatives. XXI. Crystal structure of a liquid crystalline ferrocene derivative, 1,1'-bis[3-[4-(4-methoxyphenoxycarbonyl)phenoxy]propyloxycarbonyl]ferrocene

2009 ◽  
Vol 42 (1) ◽  
pp. 63-68 ◽  
Author(s):  
Takashi Okabe ◽  
Keisuke Nakazaki ◽  
Tsuyoshi Igaue ◽  
Naotake Nakamura ◽  
Bertrand Donnio ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Nematic Phase ◽  
Liquid Crystalline ◽  
Stacking Interactions ◽  
X Ray Diffraction ◽  
Ferrocene Derivatives ◽  
Ferrocene Derivative ◽  
X Ray ◽  
Flexible Spacer ◽  
Packing Arrangement

The crystal structure of the title 1,1′-disubstituted ferrocene derivative was determined by X-ray diffraction using a single crystal. This compound exhibits a nematic phase only. The X-ray structure analysis revealed that the two substituents lie in the same direction (`U' shape) and the flexible spacer adopts agaucheconformation. These conformations are strongly related to the formation of a rod-like shape, which favors liquid crystalline behavior. In the crystal structure, C—H...π, π–π and T-stacking interactions were observed. It is considered that these interactions play a major role in stabilizing the molecular packing arrangement and the mesomorphism.

scholarly journals Reciprocal Powered Time model for Release Kinetic Analysis of Ibuprofen Solid Dispersions in Oleaster Powder, Microcrystalline Cellulose and Crospovidone

2010 ◽  
Vol 13 (2) ◽  
pp. 152 ◽  
Author(s):  
Ghobad Mohammadi ◽  
Mohammad Barzegar-Jalali ◽  
Hadi Valizadeh ◽  
Hossein Nazemiyeh ◽  
Azim Barzegar-Jalali ◽  
...  
Keyword(s):  
Particle Size ◽  
Drug Release ◽  
Solid Dispersions ◽  
Release Kinetic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir ◽  
Diffraction Patterns ◽  
Release Data ◽  
Dsc Thermograms

ABSTRACT- Purpose. A physically sound derivation for reciprocal power time (RPT) model for kinetic of drug release is given. In order to enhance ibuprofen dissolution, its solid dispersions (SDs) prepared by cogrinding technique using crospovidone (CP), microcrystalline cellulose (MC) and oleaster powder (OP) as a novel carrier and the model applied to the drug release data. Methods. The drug cogrounds with the carriers were prepared and subjected to the dissolution studies. For elucidation of observed in vitro differences, FT-IR spectroscopy, X-ray diffraction patterns, DSC thermograms and laser particle size measurement were conducted. Results. All drug release data fitted very well to newly derived RPT model. The efficiency of the carriers for dissolution enhancement was in the order of: CP>OP>MC. The corresponding release kinetic parameter derived from the model, t50% (time required for 50% dissolution) for the carrier to drug ratio 2:1 were 2.7, 10.2 and 12.6 min, respectively. The efficiency of novel carrier, OP, was between CP and MC. FT-IR showed no interaction between the carriers and drug. The DSC thermograms and X-ray diffraction patterns revealed a slight reduced crystallinty in the SDs. Also grinding reduced mean particle size of drug from 150.7 to 44.4 µm. Conclusion. An improved derivation for RPT model was provided which the parameter of the model, t50%, unlike to previous derivations was related to the most important property of the drug i.e. its solubility. The model described very well drug release kinetics from the solid dispersions. Cogrinding was an effective technique in enhancing dissolution rate of ibuprofen. Elaeagnus angostifolia fruit powder was suggested as a novel potential hydrophilic carrier in preparing solid dispersion of ibuprofen.

Liquid crystalline alkylthia-substituted novel phthalocyanines: synthesis and characterization

2014 ◽  
Vol 18 (01n02) ◽  
pp. 139-148 ◽  
Author(s):  
Buket S. Erdoğan ◽  
Devrim Atilla ◽  
Ayşe G. Gürek ◽  
Vefa Ahsen
Keyword(s):  
Liquid Crystalline ◽  
Metal Salt ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Elemental Analyses ◽  
Diffraction Patterns ◽  
Columnar Mesophases ◽  
New Compounds ◽  
Hexagonal Columnar

Methylene-bridged tetra- and octa-alkylthia substituted metal free- and Ni ( II ) phthalocyanines were synthesized from the corresponding phthalonitrile derivatives in the presence of the anhydrous metal salt ( NiCl 2) or a strong organic base. The new compounds were fully characterized by elemental analyses, UV-vis, IR, NMR and mass spectra. The mesogenic properties of these materials were studied by differential scanning calorimetry, optical microscopy and X-ray diffraction investigations. X-ray diffraction patterns of the mesophase confirmed that the tetra- and the octa-substituted compounds formed hexagonal columnar mesophases (Colh). The mesogenic properties of these compounds were compared to that of their octa alkythia substituted phthalocyanine derivatives in the literature.

Thermal and X-Ray Studies of 1,6-Bis-[4-(trans-4-n-propylcyclohexyl) phenyl]-hexane and 3,5-Bis-[4-(trans-4-n-propylcyclohexyl) phenyl]-1,2,4-thiadiazol

1987 ◽  
Vol 42 (7) ◽  
pp. 774-776
Author(s):  
I. H. Ibrahim ◽  
W. Haase
Keyword(s):  
Nematic Phase ◽  
Liquid Crystalline ◽  
Layer Structure ◽  
Mass Density ◽  
Density Fluctuations ◽  
Smectic Layer ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Liquid Crystalline Phases ◽  
Diffraction Patterns

The liquid crystalline phases of the title compounds have been investigated by differential scanning calorimetry, optical microscopy and X -ray diffraction methods. Transition temperatures and transition enthalpies of these compounds have been determined. The diffraction photographs in the nematic phase of the first compound showed diffraction patterns corresponding to two coexisting mass density fluctuations with commensurate wavelengths, whereas a single diffraction pattern was observed in the nematic phase of the second compound. The thermal and X -ray data showed that the first compound has a quasi-smectic layer structure.

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