X-ray crystallographic structure of the two-to-one α-cyclodextrin-acetone. 9H2O compound

Binding-Induced Unfolding of 1-Bromopropane in α-Cyclodextrin

Raman multivariate curve resolution vibrational spectroscopy and X-ray crystallography are used to quantify changes in the gauche-trans conformational equilibrium of 1-bromopropane (1-BP) upon binding to α-cyclodextrin (α-CD). Both conformers of 1-BP are found to bind to α-CD, although binding favors the unfolded trans conformation. Temperature-dependent measurements of the binding-induced change in the 1-BP conformation equilibrium constant indicate that the trans conformer is both enthalpically and entropically stabilized in the host cavity.

Crystal structure of alpha-cyclodextrin-acetonitrile-hexahydrate

Crystals of the ternary alpha-cyclodextrin-acetonitrile hexahydrate inclusion complex belong to the orthorhombic space group P212121 with unit cell dimensions a = 9.479(2), b = 14.323(4), c = 37.397(9) A. 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 neighboring glucose units. Within the cavity, one acetonitrile and one water molecule are located with occupancy factors of 0.8 and 0.7. respectively. They are hydrogen bonded to disordered O65B, and acetonitrile is stabilized in position by C-5-H...N interactions. The remaining five water molecules link symmetry related cyclodextrin molecules.