title: 2,11-Dibromo-5,8-dibut-yl[4]helicene.
abstract: A racemic mixture of the title compound, C(26)H(26)Br(2), a brominated [4]helicene, crystallizes, forming columns of stacked mol-ecules. There are two crystallographically unique mol-ecules in the asymmetric unit, both with the same helical handedness. As is typical with helicene congeners, the unique mol-ecules show short inter-atomic contacts between H atoms at the fjord region, with H⋯H distances of 1.87 and 1.94 Å. Mol-ecules with the same helical handedness segregate in the crystal packing, forming homochiral columns. The stacked mol-ecules are piled in a column with alternate orientations. The shortest C⋯C distance in the stacked mol-ecules is 3.306 (4) Å.
authors.affiliation: Department of Chemistry, Tohoku University, Aoba-ku, Sendai 980-8578,  Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Isobe
authors.forename: Taisuke
authors.initials: T
authors.lastname: Matsuno
authors.forename: Shunpei
authors.initials: S
authors.lastname: Hitosugi
authors.forename: Waka
authors.initials: W
authors.lastname: Nakanishi