CRYSTAL-STRUCTURE OF ALPHA-CYCLODEXTRIN-ACETONITRILE-HEXAHYDRATE

Crystals of the ternary alpha-cyclodextrin-acetonitrile hexahydrate in clusion complex belong to the orthorhombic space group P2(1)2(1)2(1) W ith unit cell dimensions a=9.479(2), b=14.323(4), c = 37.397(9) Angstr om. Refinement against 4202 X-ray diffraction data converged at R = 0. 059. The alpha-cyclodextrin macrocycle forms a regular torus which is stabilized by intramolecular O-3-O-2 hydrogen bonds between neighborin g glucose units. Within the cavity, one acetonitrile and one water mol ecule are located with occupancy factors of 0.8 and 0.7, respectively. They are hydrogen bonded to disordered O65B, and acetonitrile is stab ilized in position by C-5-H ... N interactions. The remaining five wat er molecules link symmetry related cyclodextrin molecules. (C) 1998 El sevier Science Ltd. All rights reserved.