Aqueous Properties of Resorcinol-type Calix[4]arenes Bearing Four Alkyl Side Chains

Abstract

The resorcinol-type calix[4]arenes bearing alkyl side chains ([4]Ar-Rn, n = 4, 6, 8) have been prepared, and their aqueous properties at pH 13 have been studied by measuring the surface tension, NMR, and solubilization behavior of benzene. It is found from the surface tension measurements that the formation of micelles is promoted and the surface tension value at the critical micelle concentration cmc is decreased with increasing alkyl side chain length. The results of 2D-NMR and relaxation measurements suggest that the interaction of alkyl side chains in the micelles becomes weak, but the interaction between the resorcinol ring and the inner alkyl side group is increased with increasing alkyl side chain length. In the solubilization of benzene, benzene molecules are mainly incorporated in the resorcinol ring part of [4]Ar-R4, whereas they are solubilized in the alkyl side chains of [4]Ar-R6.