SELF INCLUSION IN A CALIX[5]ARENE STRUCTURE - STRUCTURE OF THE CONE CONFORMER OF A PENTAHYDROXY-P-TERT-BUTYLCALIX[5]ARENE

The pentahydroxy-p-tert-butylcalix[5]arene, 7,29-pentadecaene-31,32,33 ,34,-35-pentaol-n-hexane (1/0.3), C55H70O5.0.3C6H14 (I), adopts an ope n distorted chalice-shaped conformation in the solid state, primarily through O-H ... O intramolecular hydrogen bonding involving all of the aromatic hydroxyl groups. The five phenolic O ... O separations are i n the range 2.735 (7)-2.880 (8) angstrom [mean 2.793 (8) angstrom], wi th all hydroxyl H atoms disordered equally over two sites. The aromati c rings are tilted back from the calixarene cavity producing a pentago nal-shaped cavity in which the tert-butyl group of a neighboring calix [5]arene related by a c-glide is enclathrated. This self-inclusion pro cess extends through the lattice as a one-dimensional molecular 'zippe r'.