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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.


Synthesis of 4,5-di­bromo­phenanthrene (2).
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fig1: Synthesis of 4,5-di­bromo­phenanthrene (2).

Mentions: In the course of our research into non-planar polycyclic hydro­carbons, we became inter­ested in the preparation of helical phenanthrene systems bearing bulky substituents in the 4- and 5-positions. Towards that end, we undertook the synthesis of 4,5-di­bromo­phenanthrene (2) from the known di­aldehyde 1 (Suzuki et al., 2009 ▸) using a recently published procedure (Xia et al., 2012 ▸), as shown in Fig. 1 ▸. Although there is one reference to the title compound 2 in the literature (Cosmo et al., 1987a ▸), neither the procedure for its synthesis nor its X-ray crystal structure has previously been reported.


Crystal structure of 4,5-di ­ bromo ­ phenanthrene
Synthesis of 4,5-di­bromo­phenanthrene (2).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5382617&req=5

fig1: Synthesis of 4,5-di­bromo­phenanthrene (2).
Mentions: In the course of our research into non-planar polycyclic hydro­carbons, we became inter­ested in the preparation of helical phenanthrene systems bearing bulky substituents in the 4- and 5-positions. Towards that end, we undertook the synthesis of 4,5-di­bromo­phenanthrene (2) from the known di­aldehyde 1 (Suzuki et al., 2009 ▸) using a recently published procedure (Xia et al., 2012 ▸), as shown in Fig. 1 ▸. Although there is one reference to the title compound 2 in the literature (Cosmo et al., 1987a ▸), neither the procedure for its synthesis nor its X-ray crystal structure has previously been reported.

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.