AM1 calculations on inclusion complexes of cyclomaltoheptaose (beta-cyclodextrin) with 1,7-dioxaspiro[5.5]undecane and nonanal, and comparison with experimental results.

Semiempirical calculations on cyclomaltoheptaose (beta CD), 1,7-dioxaspiro[5.5]undecane (1), nonanal (2), and the inclusion complexes of beta CD with 1 and 2 were carried out using the AM1 method. The structure of beta CD after complete geometry optimization was in very good agreement with crystallographic structures. Moreover, the calculated dipole moment of beta CD was found to depend strongly upon the orientation of the primary hydroxyl groups. Different possible positions of the guest molecules in the beta CD cavity were examined, a few of them resulting in a gain of energy. These corresponded to partial inclusion of 1 from the secondary side but total inclusion of 2. Conclusions regarding the geometries of the complexes were in satisfactory agreement with the dominant structures in aqueous solutions as derived from NMR experiments. Thermodynamic data (delta H(O), delta S(O)) in aqueous solutions were obtained from van't Hoff plots using 1H NMR, and were compared with the computed heats of formation. The forces responsible for host-guest association are discussed in the light of the above results.

Inclusion complexes of cyclomaltoheptaose (beta-cyclodextrin) and its methylated derivatives with the main components of the pheromone of the olive fruit fly.

The inclusion complexes of cyclomaltoheptaose (beta CD) and heptakis(2,3,6-tri-O-methyl)cyclomaltoheptaose (TM-beta CD) with the four major components of the pheromone of the olive fruit fly (Dacus oleae), namely 1,7-dioxaspiro[5.5]undecane, (-)-alpha-pinene, nonanal, and ethyl dodecanoate, and the complex of heptakis(2,6-di-O-methyl)cyclomaltoheptaose (DM-beta CD) with 1,7-dioxaspiro[5.5]undecane were studied. The complexes were characterised in the solid state by differential scanning calorimetry and X-ray powder diffraction. In aqueous solution, the structure of the complexes was investigated by 1H NMR spectroscopy. In solution, 1,7-dioxaspiro[5.5]undecane, (-)-alpha-pinene, and nonanal enter the cavity of the cyclo-oligosaccharides. Association constants for some of these complexes were also measured. The complexes of ethyl dodecanoate did not provide evidence of their structure in solution. This was attributed to the existence of negligible amounts of these complexes in water due to the combined effects of low solubility and low association constant.

The crystal structure of the inclusion complex of cyclomaltoheptaose (beta-cyclodextrin) with 4-tert-butyltoluene.

The crystal of the 1:1 complex of 4-tert-butyltoluene with cyclomaltoheptaose (beta-cyclodextrin, beta CD) is triclinic P1 with a = 15.562(2), b = 15.564(4), c = 15.835(3) A, alpha = 102.11(2), beta = 102.15(1), gamma = 103.64(2) degrees, V = 3505(1) A3, and Z = 2. The two independent beta CD molecules in the asymmetric unit form a dimer by hydrogen bonding involving HO-3, which accommodates two molecules of the guest. The hydrophobic guests are enclosed completely in the beta CD cavities with the tert-butyl groups in the hydrophobic region beneath the primary hydroxyl groups. The aromatic rings have two orientations and their toluene methyl moieties could not be located but were calculated to be at the interface of the two monomers. The dimers form channels along the c axis. The inter-dimer space is filled with 17 molecules of water distributed over 25 sites. A dense network of hydrogen bonds is formed, involving the beta CD hydroxyl groups and water molecules.

The crystal structure of the inclusion complex of cyclo-maltoheptaose (beta-cyclodextrin) with 3,3-dimethylbutylamine.

The crystal of the 1:1 complex of 3,3-dimethylbutylamine with cyclomaltoheptaose (beta CD, beta-cyclodextrin) is monoclinic C2 with a = 19.187(9), b = 24.56(1), c = 15.893(7) A, beta = 108.77(4) degrees, V = 7091 A3, and Z = 4. Two beta CD molecules, held together by intermolecular hydrogen bonds involving HO-3, form dimers, in the cavities of which two 3,3-dimethylbutylamine and two water molecules are accommodated. The guest molecule is completely enclosed in the cavity. The amino group is located at the secondary-hydroxyl-group side, and is hydrogen-bonded to the entrapped water molecules. The dimers form channels along the c axis. The inter-dimer space is filled with 10.7 water molecules that are distributed over 14 sites, and there is a dense network of hydrogen bonds involving the water molecules and the beta CD hydroxyl groups.