Crystal structures of cyclomaltohexaose (α-cyclodextrin) complexes with p-bromophenol and m-bromophenol

Crystal structures of cyclomaltohexose (α-cyclodextrin) complexes with p-bromophenol and m-bromophenol have been determined by single-crystal X-ray diffraction. The space group of the α-cyclodextrin–p-bromophenol complex is P212121 with unit cell dimensions of a=15.318(3), b=24.733(3), c=13.457(2) Å, and that of the α-cyclodextrin–m-bromophenol complex is P21212 with unit cell dimensions of a=25.858(7), b=27.263(8), c=8.145(3) Å. In crystals, the α-cyclodextrin–p-bromophenol complex and the α-cyclodextrin–m-bromophenol complex form a layer-type and a channel-type molecular packing structure, respectively. The intermolecular hydrogen-bond interactions of the hydroxyl groups of bromophenols are closely related to the molecular packing structure.