Generation of possible crystal structures from molecular structure for low-polarity organic compounds

1991 ◽  
Vol 113 (12) ◽  
pp. 4622-4629 ◽  
Author(s):  
A. Gavezzotti
Keyword(s):  
Molecular Structure ◽  
Crystal Structures ◽  
Organic Compounds

Crystal and molecular structure of 2,6-dimethyl-3,5-di[N-methyl]carbamoyl-4-[3,4-methoxy]phenyl-l,4-dihydropyridine hemihydrate and 2,6-dimethyl-3,5-di[N-methyl]carbamoyl-4-[furan]1,4-dihydropyridine

1999 ◽  
Vol 214 (12) ◽  
Author(s):  
M. Bidya Sagar ◽  
K. Ravikumar ◽  
Y. S. Sadanandam
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Crystal Structures ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Asymmetric Unit ◽  
Full Matrix

AbstractThe crystal structures of two dihydropyridines were solved by direct methods and refined by full-matrix least-squares procedure. 2,6-Dimethyl-3,5-di[N-methyl]-carbamoyl-4-[3,4-methoxy]phenyl-1,4-dihydropyridine hemihydrate, CBoth compounds crystallize with two molecules in the asymmetric unit. In compound

scholarly journals Crystal structures of three indole derivatives: 3-ethnyl-2-methyl-1-phenylsulfonyl-1H-indole, 4-phenylsulfonyl-3H,4H-cyclopenta[b]indol-1(2H)-one and 1-{2-[(E)-2-(5-chloro-2-nitrophenyl)ethenyl]-1-phenylsulfonyl-1H-indol-3-yl}ethan-1-one chloroform monosolvate

2015 ◽  
Vol 71 (9) ◽  
pp. 1036-1041
Author(s):  
S. Gopinath ◽  
K. Sethusankar ◽  
Bose Muthu Ramalingam ◽  
Arasambattu K. Mohanakrishnan
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Dihedral Angles ◽  
Indole Derivatives ◽  
Indole Ring ◽  
Asymmetric Unit ◽  
Ring Systems ◽  
Benzene Rings ◽  
Independent Molecules

The title compounds, C17H13NO2S, (I), C17H13NO3S, (II), and C24H17ClN2O5S·CHCl3, (III), are indole derivatives. Compounds (I) and (II) crystalize with two independent molecules in the asymmetric unit. The indole ring systems in all three structures deviate only slightly from planarity, with dihedral angles between the planes of the pyrrole and benzene rings spanning the tight range 0.20 (9)–1.65 (9)°. These indole ring systems, in turn, are almost orthogonal to the phenylsulfonyl rings [range of dihedral angles between mean planes = 77.21 (8)–89.26 (8)°]. In the three compounds, the molecular structure is stabilized by intramolecular C—H...O hydrogen bonds, generatingS(6) ring motifs with the sulfone O atom. In compounds (I) and (II), the two independent molecules are linked by C—H...O hydrogen bonds and C—H...π interactions, while in compound (III), the molecules are linked by C—H...O hydrogen bonds, generatingR22(22) inversion dimers.

scholarly journals FIDEL: A new method for SDPD of nanocrystalline organic compounds

2014 ◽  
Vol 70 (a1) ◽  
pp. C134-C134
Author(s):  
Martin Schmidt ◽  
Stefan Habermehl ◽  
Philipp Moerschel ◽  
Pierre Eisenbrandt
Keyword(s):  
Crystal Structures ◽  
Rietveld Refinement ◽  
Organic Compounds ◽  
Structure Data ◽  
Structural Model ◽  
Lattice Energy ◽  
Lattice Parameters ◽  
Low Energy ◽  
Powder Pattern ◽  
Field Methods

Rietveld refinements generally fail, if the lattice parameters of the structural model differ more than slightly from the correct lattice parameters and the simulated reflections do not overlap with the experimental ones. For molecular crystals, we have developed a more robust fitting algorithm, which uses the cross-correlation function of calculated and experimental powder patterns, and allows a FIt with DEviating Lattice parameters (FIDEL). The method is also successful for nanocrystalline organic compounds showing only 10-20 peaks in their powder diagrams. The FIDEL method has proven to be useful for various applications, including refinements starting from (1) structure data of an isostructural chemical derivative; (2) structure data of an isostructural hydrate or solvate; (3) structure data from measurements at another temperature (e.g. for fitting a room-temperature powder diagram starting with a structure determined from a single-crystal measurement at 100K). FIDEL is also used for determining crystal structures from non-indexed powder diagrams of nanocrystalline organic compounds. Three steps are performed: (1) Prediction of possible crystal structures in various space groups using global lattice-energy minimizations by force-field methods. (2) FIDEL fit of 100 to 600 low-energy structures to the experimental powder pattern. The structure candidate leading to the correct structure results in a significantly better fit than all other structures. (3) Rietveld refinement. The FIDEL method was used to determine the hitherto unknown crystal structure of the nanocrystalline alpha-phase of 2,9-dichloroquinacridone (C20H10Cl2N2O2). The upper part of the figure shows the experimental powder pattern and the simulated powder diagram of one of the predicted low-energy structures before any fitting. The lower part displays the result of the FIDEL fit, before the Rietveld refinement.

Theoretical Study on Thermal Hazardous Properties of C18H10O11 and C18H18O7 Organic Peroxides

2013 ◽  
Vol 787 ◽  
pp. 301-305
Author(s):  
Yun Bo He ◽  
Wei Wang ◽  
Shi Xiong Wang ◽  
Xiang Jun Yang ◽  
Hong Guo
Keyword(s):  
Molecular Structure ◽  
Thermal Decomposition ◽  
Quantum Chemistry ◽  
Organic Compounds ◽  
Theoretical Study ◽  
Organic Peroxides ◽  
Quantum Chemistry Calculation ◽  
The Past ◽  
Chemistry Calculation ◽  
The Stability

The thermal decomposition of organic peroxides are widely used as coagulant for organic compounds, however, its thermal hazardous characteristics have already caused serious accidents in chemical industries, which limited its application in much more strict conditions. Organic peroxides of C18H10O11 and C18H18O7 are two new candidates fitted for industrial explosive. However, as we best known there is little reports available on the geometry structure in the past decades. In this work, by means of quantum chemistry calculation, the relation of safety with molecular structure of C18H10O11 and C18H18O7 are discussed. The molecules with more activity O and the activity part more dispersedly exhibit higher stable, and the configuration has good safety. All the energy of molecule b is higher than that of molecule a. The stability of different configurations are 6a>7a>8a>9a>5a>1a>4a>3a=2a and 1b>7b>5b>6b>4b>2b>3b>8b, respectively, suggesting the structures of 6a,3a,2a,1b,8b exhibit high safety.

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