Monoclinic form of 1,2,4,5-tetracyclohexylbenzene

The molecule of the title compound, C30H46, has a crystallographically imposed inversion center and the cyclohexyl groups are oriented with their methine H atoms pointing towards one another (H⋯H = 1.99 Å). The cyclohexyl groups adopt chair conformations. A significant C—H⋯π interaction assembles molecules into layers parallel to (100).

The molecule of the title compound, C 30 H 46 , has a crystallographically imposed inversion center and the cyclohexyl groups are oriented with their methine H atoms pointing towards one another (HÁ Á ÁH = 1.99 Å ). The cyclohexyl groups adopt chair conformations. A significant C-HÁ Á Á interaction assembles molecules into layers parallel to (100).

Experimental
Cg is the centroid of the aromatic ring.
(C 30 H 46 ) from hot methylcyclohexane forms colorless needle-shaped crystals together with a smaller quantity having a distinctly different block-shaped morphology. The latter is monoclinic with the molecule having crystallographically imposed centrosymmetry. The cyclohexyl rings adopt the chair conformation and are oriented with their methine hydrogen atoms pointed towards one another (H···H distance 1.99 Å). This contrasts with the structure of 1-bromo-2,4,6-tricyclohexylbenzene (Mague et al., 2008b) where the methine hydrogen atoms of the meta-disposed cyclohexyl groups point towards the intervening ring substituent. This is presumably to minimize intramolecular contacts between the ortho-disposed cyclohexyl rings. Indeed, there are very few close contacts involving these substituents, the shortest being H4···H10 (1.99 Å), H3···H5a (2.18 Å) and H3···H11a' (2.07 Å). The plane defined by the atoms C5, C6, C8, C9 ("seat" of the chair) is inclined to the plane of the aromatic ring by 79.0 (2)° while that for the other cyclohexyl ring (C11, C12, C14, C15) is inclined at an angle of only 61.7 (2)°. A significant C-H···π interaction occurs between C6-H6A and the center of gravity (Cg) of the aromatic ring in the molecule at 1 − x, 1/2 + y, 0.5 − z where the H-Cg distance is 2.62 Å and the C-H···Cg angle is 150°. This interaction forms layers of molecules parallel to (100) at approximately x = 0.5.
The mixture was allowed to slowly warm to −15° C and the stirring continued for 2 h. The resulting yellow-orange mixture was quenched by pouring it over 800 g of ice and, after thawing, was filtered. The organic layer of the filtrate was separated off, washed several times with water and reduced to a small volume under reduced pressure. After standing for 1 week, a precipitate formed which was filtered off, washed with 10% aqueous HCl and collected by filtration to provide 16.

Special details
Experimental. The diffraction data were collected in three sets of 606 frames (ω scans, 0.3°/scan) at φ settings of 0, 120 and 240°.