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Crystal structure of 4,5-di ­ bromo ­ phenanthrene

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ABSTRACT

The synthesis and crystal structure of the title compound, C14H8Br2, is described. The mol­ecule is positioned on a twofold rotation axis and the asymmetric unit consists of half a mol­ecule with the other half being generated by symmetry. The presence of two large bromine atoms in the bay region significantly distorts the mol­ecule from planarity and the mean planes of the two terminal rings of the phenanthrene system are twisted away from each other by 28.51 (14)°. The torsion angle between the two C—Br bonds is 74.70 (14)° and the distance between the two Br atoms is 3.2777 (13) Å. The mol­ecules pack in layers in the crystal, with the centroids of the central rings of the phenanthrene units in adjacent layers separated by a distance of 4.0287 (10) Å. These centroids are shifted by 2.266 (6) Å relative to each other, indicating slippage in the stacking arrangement. Furthermore, the distance between the centroids of the terminal and central rings of the phenanthrene units in adjacent layers is slightly shorter at 3.7533 (19) Å. While all of the mol­ecules within each layer are oriented in the same direction, those in adjacent layers are oriented in the opposite direction, leading to anti-parallel stacks.

No MeSH data available.


The 4,5-dihalo derivatives of phenanthrene shown with conventional chemical numbering. This figure is used as a reference for the data in Table 1 ▸.
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fig3: The 4,5-dihalo derivatives of phenanthrene shown with conventional chemical numbering. This figure is used as a reference for the data in Table 1 ▸.

Mentions: The asymmetric unit consists of half a mol­ecule with the other half generated by symmetry as the mol­ecule is positioned on a twofold rotation axis that bis­ects the central ring. The crystal structure shows a deformed phenanthrene framework (Fig. 2 ▸) in which the planes of the two terminal rings are twisted away from each other by 28.51 (14)° and the torsion angle between the two C—Br bonds (Br1—C4—C4′—Br1′) is 74.70 (14)°. The C4—C5—C5′—C4′ torsion angle is 32.8 (6)°, and the distance between the two bromine atoms is 3.277 (13) Å, a value consistent with a previous report (Cosmo et al., 1987a ▸). A comparison of the key structural features of the title compound 2 to those of other known 4,5-dihalo­phenanthrenes (Cosmo et al., 1987b ▸; Bock et al., 1998 ▸) is presented in Table 1 ▸ with reference to the general structure shown in Fig. 3 ▸. The distance between the two halogen atoms, and the torsion angle between the two carbon–halogen bonds (X—C4—C5—X), increase as expected with the increasing size of the halogen atom. Inter­estingly, however, the distortion of the phenanthrene framework, as measured by either the angle between the mean planes of the terminal rings A and C, or the C4—C4′—C5′—C5 torsion angle (see Fig. 3 ▸), is the largest for the di­chloro derivative 4 (Table 1 ▸), larger than for the di­bromo and diodo compounds. A combination of both size and electronegativity may account for compound 4 showing the largest twist of the phenanthrene system in the series of 4,5-dihalophenathrene compounds.


Crystal structure of 4,5-di ­ bromo ­ phenanthrene
The 4,5-dihalo derivatives of phenanthrene shown with conventional chemical numbering. This figure is used as a reference for the data in Table 1 ▸.
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Related In: Results  -  Collection

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fig3: The 4,5-dihalo derivatives of phenanthrene shown with conventional chemical numbering. This figure is used as a reference for the data in Table 1 ▸.
Mentions: The asymmetric unit consists of half a mol­ecule with the other half generated by symmetry as the mol­ecule is positioned on a twofold rotation axis that bis­ects the central ring. The crystal structure shows a deformed phenanthrene framework (Fig. 2 ▸) in which the planes of the two terminal rings are twisted away from each other by 28.51 (14)° and the torsion angle between the two C—Br bonds (Br1—C4—C4′—Br1′) is 74.70 (14)°. The C4—C5—C5′—C4′ torsion angle is 32.8 (6)°, and the distance between the two bromine atoms is 3.277 (13) Å, a value consistent with a previous report (Cosmo et al., 1987a ▸). A comparison of the key structural features of the title compound 2 to those of other known 4,5-dihalo­phenanthrenes (Cosmo et al., 1987b ▸; Bock et al., 1998 ▸) is presented in Table 1 ▸ with reference to the general structure shown in Fig. 3 ▸. The distance between the two halogen atoms, and the torsion angle between the two carbon–halogen bonds (X—C4—C5—X), increase as expected with the increasing size of the halogen atom. Inter­estingly, however, the distortion of the phenanthrene framework, as measured by either the angle between the mean planes of the terminal rings A and C, or the C4—C4′—C5′—C5 torsion angle (see Fig. 3 ▸), is the largest for the di­chloro derivative 4 (Table 1 ▸), larger than for the di­bromo and diodo compounds. A combination of both size and electronegativity may account for compound 4 showing the largest twist of the phenanthrene system in the series of 4,5-dihalophenathrene compounds.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

The synthesis and crystal structure of the title compound, C14H8Br2, is described. The mol­ecule is positioned on a twofold rotation axis and the asymmetric unit consists of half a mol­ecule with the other half being generated by symmetry. The presence of two large bromine atoms in the bay region significantly distorts the mol­ecule from planarity and the mean planes of the two terminal rings of the phenanthrene system are twisted away from each other by 28.51 (14)°. The torsion angle between the two C—Br bonds is 74.70 (14)° and the distance between the two Br atoms is 3.2777 (13) Å. The mol­ecules pack in layers in the crystal, with the centroids of the central rings of the phenanthrene units in adjacent layers separated by a distance of 4.0287 (10) Å. These centroids are shifted by 2.266 (6) Å relative to each other, indicating slippage in the stacking arrangement. Furthermore, the distance between the centroids of the terminal and central rings of the phenanthrene units in adjacent layers is slightly shorter at 3.7533 (19) Å. While all of the mol­ecules within each layer are oriented in the same direction, those in adjacent layers are oriented in the opposite direction, leading to anti-parallel stacks.

No MeSH data available.