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Crystal structure of Pigment Red 254 from X-ray powder diffraction data

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ABSTRACT

The crystal structure of Pigment Red 254 [P.R. 254, C18H10Cl2N2O2; systematic name: 3,6-bis­(4-chloro­phen­yl)-2,5-di­hydro­pyrrolo­[3,4-c]pyrrole-1,4-dione] was solved from laboratory X-ray powder diffraction data using the simulated annealing method followed by Rietveld refinement because the very low solubility of the pigment in all solvents impedes the growth of single crystals suitable for X-ray analysis. The mol­ecule lies across an inversion center. The dihedral angle between the benzene ring and the pyrrole ring in the unique part of the mol­ecule is 11.1 (2)°. In the crystal, mol­ecules are linked via N—H⋯O hydrogen bonds, forming chains along [110] incorporating R22(8) rings.

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Rietveld plot of P.R. 254. The experimental data points are shown as crosses, the calculated pattern as a solid line and the difference curve as line under the profiles. Tick marks are shown as vertical dashes (laboratory data).
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fig5: Rietveld plot of P.R. 254. The experimental data points are shown as crosses, the calculated pattern as a solid line and the difference curve as line under the profiles. Tick marks are shown as vertical dashes (laboratory data).

Mentions: Suitable chemical restraints were applied for all bond lengths, valence angles and the planarity of the aromatic ring systems (including the five-membered condensed system). Anisotropic peak broadening was included to allow the peak profiles to be described accurately. The discrepancies between the observed and the calculated profile appeared to systematically depend on the hkl indices of the reflections, indicating preferred orientation in the [001] direction. The March–Dollase formula (Dollase, 1986 ▸) was used. The diffraction profiles and the differences between the measured and calculated profiles are shown in Fig. 5 ▸.


Crystal structure of Pigment Red 254 from X-ray powder diffraction data
Rietveld plot of P.R. 254. The experimental data points are shown as crosses, the calculated pattern as a solid line and the difference curve as line under the profiles. Tick marks are shown as vertical dashes (laboratory data).
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5382609&req=5

fig5: Rietveld plot of P.R. 254. The experimental data points are shown as crosses, the calculated pattern as a solid line and the difference curve as line under the profiles. Tick marks are shown as vertical dashes (laboratory data).
Mentions: Suitable chemical restraints were applied for all bond lengths, valence angles and the planarity of the aromatic ring systems (including the five-membered condensed system). Anisotropic peak broadening was included to allow the peak profiles to be described accurately. The discrepancies between the observed and the calculated profile appeared to systematically depend on the hkl indices of the reflections, indicating preferred orientation in the [001] direction. The March–Dollase formula (Dollase, 1986 ▸) was used. The diffraction profiles and the differences between the measured and calculated profiles are shown in Fig. 5 ▸.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

The crystal structure of Pigment Red 254 [P.R. 254, C18H10Cl2N2O2; systematic name: 3,6-bis­(4-chloro­phen­yl)-2,5-di­hydro­pyrrolo­[3,4-c]pyrrole-1,4-dione] was solved from laboratory X-ray powder diffraction data using the simulated annealing method followed by Rietveld refinement because the very low solubility of the pigment in all solvents impedes the growth of single crystals suitable for X-ray analysis. The mol­ecule lies across an inversion center. The dihedral angle between the benzene ring and the pyrrole ring in the unique part of the mol­ecule is 11.1 (2)°. In the crystal, mol­ecules are linked via N—H⋯O hydrogen bonds, forming chains along [110] incorporating R22(8) rings.

No MeSH data available.


Related in: MedlinePlus