G. Ferguson et al., STRUCTURE OF THE PARTIAL CONE CONFORMER OF 27,28-TETRAKIS[(2-PYRIDYLMETHYL)-OXY]CALIX[4]ARENE, Acta crystallographica. Section C, Crystal structure communications, 49, 1993, pp. 1537-1540
The partial cone conformer of ,5,7(28),9,11,13(27),15,17,19(26),21,23-
dodecaene, (I), adopts a conformation in which the pendant OCH2py grou
p of the rotated aryl ring is oriented away from the calixarene cavity
produced by the other three aryl rings, with its N atom exo to the ca
lixarene cup. The orientation of the four aromatic rings is such that
two rings are almost parallel to each other and the other two are at a
n angle of 42-degrees. This conformation precludes any solvent molecul
e being enclathrated within the small molecular cavity.