Two structural types of 1,3-alternate tetrapropoxycalix[4]arene derivatives in the solid state

The solid state structures of seven tetrapropoxycalix[4]arene derivatives immobilised in a 1,3-alternate conformation were determined using single-crystal X-ray crystallography. The cavity shapes of investigated derivatives (upper rim unsubstituted, distally di-substituted and tetra-substituted) and the nature of intermolecular interactions in molecular packing were compared. The results indicate that there are only two structural types adopted by basic tetrapropoxycalix[4]arene derivatives in the 1,3-alternate conformation.