Cavity shaped host–guest interaction of distally dialkylated calix[4]arenes with 1-chloro-4-(trifluoromethyl)benzene Original Research Article

The conformation of the conic molecular cavity in the ‘host’ properties of 1,3 dialkylated calixarenes were examined by spectrofluorometric and quantum-chemical methods. The size of the ‘host’ molecular cavity was influenced by the nature of substituents in distal position. As model guest molecule, 1-chloro-4-(trifluoromethyl)benzene (BTF) from the pesticide related organic series was chosen. The dependence of the interaction between the neutral molecule and the calixarene on the extent of distorsion in the conformation of ‘host’ cavity was obtained. The ‘pinched cone’ conformer of 1,3-substituted calix[4]arenes seems to form a complex with electron-deficient neutral aromatics by predominant π–π type in-teraction.