Direct correlation among crystal structure, mechanical behaviour and tabletability in a trimorphic molecular compound

CrystEngComm ◽  
2012 ◽  
Vol 14 (11) ◽  
pp. 3865 ◽  
Author(s):  
Partha Pratim Bag ◽  
Miles Chen ◽  
Changquan Calvin Sun ◽  
C. Malla Reddy
Keyword(s):  
Crystal Structure ◽  
Mechanical Behaviour ◽  
Molecular Compound

scholarly journals A non-mathematical introduction to the superspace description of modulated structures

2009 ◽  
Vol 65 (3) ◽  
pp. 249-268 ◽  
Author(s):  
Trixie Wagner ◽  
Andreas Schönleber
Keyword(s):  
Crystal Structure ◽  
Data Processing ◽  
Reciprocal Lattice ◽  
Molecular Compound ◽  
Modulated Structure ◽  
X Ray ◽  
Modulated Structures ◽  
Structure Solution ◽  
Superspace Description ◽  
Complete Process

The X-ray analysis of (6R,7aS)-6-(tert-butyl-dimethylsilanyloxy)-1-hydroxy-2-phenyl-5,6,7,7a-tetrahydropyrrolizin-3-one, C19H27NO3Si, revealed a diffraction pattern which is typical for modulated structures: strong Bragg peaks surrounded by weaker reflections which cannot be indexed with the same three reciprocal lattice vectors that are used to describe the strong peaks. For this class of crystal structures the concept of superspace has been developed which, however, for many crystallographers still constitutes a Gordian Knot. As a possible tool to cut this knot the crystal structure of the above-mentioned tetrahydropyrrolizinone derivative is presented as an illustrative example for handling and describing the modulated structure of a typical pharmaceutical (i.e. molecular) compound. Having established a working knowledge of the concepts and terminology of the superspace approach a concise and detailed description of the complete process of peak indexing, data processing, structure solution and structure interpretation is presented for the incommensurately modulated crystal structure of the above-mentioned compound. The superspace symmetry applied is P21(α0γ)0; the (incommensurate) q vector components at 100 K are α = 0.1422 (2) and γ = 0.3839 (8).

Weak ferromagnetism in the molecular compound Cu(ta)(3-pic).cntdot.H2O(ta=terephthalato,3-pic=3-picoline). Crystal structure of Cu(ta)(3-pic)2.cntdot.0.5(3-pic).cntdot.0.5CH3OH

1992 ◽  
Vol 31 (4) ◽  
pp. 625-631 ◽  
Author(s):  
Evangelos Bakalbassis ◽  
Pierre Bergerat ◽  
Olivier Kahn ◽  
Suzanne Jeannin ◽  
Yves Jeannin ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Weak Ferromagnetism ◽  
Molecular Compound

Preparation, crystal structure and photochemistry of a novel molecular compound between duroquinone and durene

1994 ◽  
Vol 35 (27) ◽  
pp. 4801-4804 ◽  
Author(s):  
Hideko Koshima ◽  
Xinkan Yao ◽  
Honggen Wang ◽  
Ruji Wang ◽  
Teruo Matsuura
Keyword(s):  
Crystal Structure ◽  
Molecular Compound

The crystal structure of the π -molecular compound pyrene : p -benzoquinone

1976 ◽  
Vol 347 (1650) ◽  
pp. 419-434 ◽  
Keyword(s):  
Crystal Structure ◽  
Interplanar Spacing ◽  
Direct Methods ◽  
Unit Cell ◽  
Unusual Feature ◽  
Molecular Compound ◽  
Space Group ◽  
Tetragonal System ◽  
Molecular Compounds

Pyrene : p -benzoquinone (C 16 H 10 :C 6 H 4 O 2 ) crystallizes in the tetragonal system, with cell constants a = 7.698(2), c = 25.570(5) Å, space group P 4 1 and four formula units per unit cell. The structure was solved by direct methods and refined to an R value of 0.048 for 778 observed reflexions. The pyrene and p -benzoquinone molecules are arranged alternately in mixed stacks, with interplanar spacing of 3.49 Å and an angle of 1.1° between molecular planes. The mixed stacks are arranged in sheets parallel to (001), successive sheets being related by the 4 1 axis. This type of arrangement of mixed stacks has not been encountered previously among π -molecular compounds. Neither the stacks nor their arrangement are centrosymmetric; as the component molecules are both centrosymmetric this constitutes a second unusual feature of this crystal structure.

scholarly journals Crystal Structure of the 1:1 Molecular Compound 1,4-Dioxan, Sulphuric Acid.

1960 ◽  
Vol 14 ◽  
pp. 398-406 ◽  
Author(s):  
O. Hassel ◽  
Chr. Rømming ◽  
Thor A. Bak ◽  
Susanne Refn ◽  
Gertrud Westin
Keyword(s):  
Crystal Structure ◽  
Sulphuric Acid ◽  
Molecular Compound

Structural study on syndiotactic polystyrene: 4. Formation and crystal structure of molecular compound with iodine

Polymer ◽  
1993 ◽  
Vol 34 (23) ◽  
pp. 4841-4845 ◽  
Author(s):  
Yozo Chatani ◽  
Tomoko Inagaki ◽  
Yukio Shimane ◽  
Haruo Shikuma
Keyword(s):  
Crystal Structure ◽  
Structural Study ◽  
Syndiotactic Polystyrene ◽  
Molecular Compound
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