Molecular inclusion in functionalized macrocycles. Part 8. The crystal and molecular structure of calix[4]arene from phenol and its (1 : 1) and (3 : 1) acetone clathrates

Abstract

The cyclic tetramer (2c), formally derived from the condensation of phenol and formaldehyde but actually obtained by dealkylating p-t-butyl- and p-octylcalix[4]arenes, crystallizes from acetone in two crystal forms. The first one, obtained in the presence of 1,2,4,5-tetramethylbenzene, is the (2c)–acetone (1 : 1) clathrate, orthorhombic, space group Pnma, a= 17.010(8), b= 14.127(6), c= 10.667(3)Å, Z= 4, final R value 0.090. The second, obtained from pure acetone or in the presence of thymol, is the (2c)–acetone (3 : 1) clathrate, space group P6₃/m, a=b= 14.543(5), c= 18.228(7)Å, γ= 120°, final R value 0.070. The geometry of macrocycle (2c) in the two forms, in the ‘cone’ conformation in both cases, is slightly different. The orthorhombic crystals show a molecular arrangement of an intercalatoclathrate type and the hexagonal one a tubulato-clathrate type.