THE CRYSTAL-STRUCTURE OF THE 2-PYRIDYLMETHYL)OXY]-27,28-DIHYDROXY-CALIX[4]ARENE ETHANOL 1 1 INCLUSION COMPLEX/

The crystal structure of the title compound (1 . C2H5OH) has been dete rmined by single-crystal X-ray analysis and refined to an R-value of 0 .074 for 2732 observed reflections [I > 2.0sigma(I)]. Crystals are tri clinic, space group P1BAR, with a = 13.6150(18), b = 13.7195(11), c = 16.5497(16) angstrom, alpha = 73.132(7), beta = 66.165(9), gamma = 65. 580(8)degrees and Z = 2. Calix[4]arene (1) adopts a relatively open di storted cone conformation in the solid state, with two pendant syn-pro ximal O-CH2-Py groups. The major conformation determining features in (1 . C2H5OH) are the presence of (a) an intramolecular O-H...O hydroge n bond between adjacent proximal phenolic oxygens, O...O 2.719(7) angs trom, and (b) an intramolecular O-H...N hydrogen bond between a phenol ic oxygen and a proximal pyridinyl nitrogen, O...N 2.810(8) angstrom. The intramolecular hydrogen bonding and the interplanar angles of 65.1 (3) and 50.7(3)degrees between opposite aromatic rings facilitate the inclusion of an ethanol molecule within the calixarene cup.