X-Ray Structure of an Inclusion Compound of 5,5?-Biscalix[4]arene-hexabenzoate with Toluene

The structure of the 1:3 complex between 5,5'-biscalix[4]arene- hexabenzoate and toluene has been determined by a single crystal X-ray diffraction study. The two calix[4]arene subunits of the 5,5'-biscalix[4] arene system are related by an inversion center and are joined by an eclipsed biphenyl para-para linkage. Each calix[4]arene moiety dispalys a 1,3-alternate conformation and includes a toluene molecule within two opposite benzoate groups, while a third toluene molecule lies close to a crystallographic inversion center.