CRYSTAL AND MOLECULAR STRUCTURE OF BETA-CHLOROETHYL TRIPTYCENE

β chloroethyl triptycene, C22H17CI, crystallizes with two molecules per asymmetric unit in space group P2i/c with a = 15.99 A, 6 = 15.46 A, c = 16.48 Å, and β = 126° 42'. The triptycene nucleus has an approximate threefold axis of symmetry. The chloroethyl chain lies nearly in the plane of one of the phenyl groups and is oriented in the trans conformation with respect to that phenyl group. The three phenyl groups in each molecule have normal C-C bond lengths near 1.39 Å, while the apical bonds in the eight-membered cage have an average length of 1.53 A. The apical angles in the cage are near 105° while the angles in the cage adjacent to the phenyl groups are near 113°. Phases for the structure determination were obtained directly from the magnitudes of the intensities by the use of the symbolic-addition procedure. © 1969, Walter de Gruyter. All rights reserved.