1-Bromo-2,4,6-tricyclohexylbenzene

The title compound, C24H25Br, packs efficiently in the crystal structure with no solvent-accessible voids and several intermolecular H⋯H contacts approximating the sum of the van der Waals radii. The molecule is quite crowded, with intramolecular Br⋯H and C⋯H contacts ca 0.38 and 0.30 Å, respectively, less than the sum of the corresponding van der Waals radii. All cyclohexyl rings adopt chair conformations with the ‘seat’ of the chair inclined at approximately 57–81° to the mean plane of the benzene ring, while those ortho to bromine have their centroids displaced in opposite directions from this plane.

The title compound, C 24 H 25 Br, packs efficiently in the crystal structure with no solvent-accessible voids and several intermolecular HÁ Á ÁH contacts approximating the sum of the van der Waals radii. The molecule is quite crowded, with intramolecular BrÁ Á ÁH and CÁ Á ÁH contacts ca 0.38 and 0.30 Å , respectively, less than the sum of the corresponding van der Waals radii. All cyclohexyl rings adopt chair conformations with the 'seat' of the chair inclined at approximately 57-81 to the mean plane of the benzene ring, while those ortho to bromine have their centroids displaced in opposite directions from this plane.

Experimental
We thank the Chemistry Department of Tulane University for support of the X-ray laboratory, and the Louisiana Board of Regents through the Louisiana Educational Quality Support Fund (Grant LEQSF (2003-2003-ENH-TR-67) for the purchase of the APEX diffractometer.
angle of 122.4 (3)° with C19 0.07 (1) Å below the plane of the aromatic ring while the plane defined by C14, C15, C17, C18 makes an angle of 81.5 (3)° with the latter plane. The tilt is towards C5 and C13 lies in the plane of the aromatic ring.
Additionally, the center of gravity of the C7-C12 ring lies 0.23 (1) Å above the mean plane of the aromatic ring while that of the C19-C24 ring lies 0.51 (1) Å below it. This contrasts with 2,6-dicyclohexyl-3,5-di-tert-butylphenol (Vilardo et al., 2000) and 2,3,6-tricyclohexylbiphenyl (Columbus et al., 1994) where the centers of gravity of the corresponding cyclohexyl groups are essentially in the plane of the aromatic ring (in the former this is required by symmetry). The methine H atoms H7 and H19 point towards the bromine which is the orientation seen in 2,3,6-tricyclohexylbiphenyl but opposite from that in 2,6-dicyclohexyl-3,5-di-tert-butylphenol. All three cyclohexyl groups adopt chair conformations with the pertinent puckering parameters (Cremer & Pople, 1975) listed in Table 1. There are 20 intermolecular H···H contacts that are 0.09 (2)-0.13 (2) Å less than the sum of the van der Waals radii and 14 equal to this sum indicative of the compact molecular packing. In addition there are 12 intramolecular H···C contacts 0.07 (2)-0.30 (2) Å less and 9 intramolecular H···H contacts 0.05 (3)-0.30 (3) Å less than the sums of the respective van der Waals radii. This contrasts with 2,6-dicyclohexyl-3,5-di-tert -butylphenol where no such short contacts are seen and 2,3,6-tricyclohexylbiphenyl where there is one C-H···Cg (Cg is the center of gravity of the central aromatic ring) interaction with H···Cg = 2.71 Å and a C-H···Cg angle of 161°.

Experimental
The title compound was prepared by the literature method (Kouldelka et al., 1985).

Refinement
H atoms were included in calculated postions with C-H = 0.95 − 1.00Å and were included in the riding-model approximation with U iso (H) = 1.2U eq (C).