New water-soluble host molecules derived from calix[6]arene

4-Sulfonate derivatives of calix[6]arene and O-n-hexylcalix[6]arene (1a and 1b, respectively) were synthesized. Measurements using fluorescence and absorption spectral probes indicated that the cavity of calix-[6]arene can accept a naphthalene molecule but not a pyrene molecule and that (1b) has a hydrophobic cavity constructed from the aggregate of the hexyl groups while (1a) provides a reaction field apparently more polar than water. This is the first example for water-soluble host molecules derived from calix[6]arene.