Molecular inclusion in functionalized macrocycles. Part 5. The crystal and molecular structure of 25,26,27,28,29-pentahydroxycalix[5]arene–acetone (1 : 2) clathrate

Abstract

A phenol–formaldehyde cyclic pentamer, 25,26,27,28,29-pentahydroxycalix[5]arene (1), has been isolated after dealkylation of a fraction of cyclic products from the base-catalysed reaction of p-(1,1,3,3-tetramethylbutyl) phenol and formaldehyde. This compound, which is the first cyclic product with an odd number of phenolic units isolated in such reactions, is able to form an inclusion complex (1 : 2) with acetone. The symmetry of the macrocyclic molecule is C_s and the acetone molecules interact with the OH crown and with the cavity with O ⋯ O and CH₃–phenyl contacts respectively.