Inclusion complexes of the natural product gossypol. Crystal structure of the 2:1 complex of gossypol with m-Xylene

Abstract

The crystal structure of a 2: 1 inclusion complex of gossypol with m-xylene has been determined by X-ray structure analysis. The crystals of C30H30O8·0.5C8 H10 are triclinic, space group Pl-, a = 8.478(1), b = 14.087(2), c = 14.411(2) Å, α = 115,39(1), β = 75.11(1), γ = 86.80(1)°, V = 1475.2(4) Å3, Z = 2, Dx = 1.29 g cm-3, T = 295 K, μ(Cu Kα) = 7.01 cm-1. The structure has been solved by direct methods and refined to the final R value of 0.079 for 3910 observed reflections. The gossypol molecules are linked by intermolecular hydrogen bonds and form bimolecular layers parallel to the 'ab' plane. Disordered m-xylene molecules occupy cavities between these layers. All polar groups of the gossypol molecule are packed in the interior of the bilayer while non-polar groups are directed outwards. An analysis of the crystal packing of other inclusion complexes of gossypol shows that such bilayers are formed in four complexes and three of those structures are generically related to each other. © 1990 Kluwer Academic Publishers.