INTRAMOLECULAR AND INTERMOLECULAR HYDROGEN-BONDING IN A TETRAHYDROXYCALIX[4]ARENE

The title calix[4]arene, 28),21,23-dodecaene-25,26,27,28-tetraol-chlor oform (1/0.5), C45H49NO6.0.5CHCl(3), substituted at two opposite methy lene bridges by methyl and p-nitrophenyl groups, forms centrosymmetric hydrogen-bonded dimers in the solid state. This results in an eight-m embered (O-H ...)(8) ring, with O ... O distances in the range 2.637 ( 4)-2.828 (4) Angstrom. Pairs of calix[4]arene molecules (related by an other inversion centre) each have a p-methyl group of one molecule fit ting snugly into the cavity of the other, with shortest intermolecular C ... C contacts corresponding to normal C ...pi-arene interactions. The half-occupancy chloroform molecule lies disordered about another i ndependent inversion centre filling what would otherwise have been a v oid in the crystal lattice.