Structural study of C-undecylcalix[4]resorcinarene solvate with dioxane

The crystal structure of the molecular complex of C-undecylcalix[4]resorcin arene with dioxane has been determined by X-ray analysis. The asymmetric un it contains one host and four guest molecules. The calix[4]resorcinarene mo iety adopts a bowl conformation with C-4v symmetry. Four undecyl chains are axially oriented. Calix molecules are packed in a bowl-to-bowl fashion wit h alternating hydrophilic and hydrophobic layers. One of the 'hydrophilic' dioxane molecules is located at the rim of the calix moiety and is hydrogen bonded to the other one. There is no interaction to attract, or direct the dioxane molecule into the interior of the cavity. There is an exo complex formed. The dioxane molecules - located in the hydrophobic part - are highl y disordered.