The crystal and molecular structure of a reentrant nematogen: 4-cyanophenyl-3-methyl-4'-(4"-n-undecyloxy cinnamoyloxy) benzoate(11 CPMCB)

Abstract

The crystal and molecular structure of 4-cyanophenyl-3-methyl-4'-(4"-n-undecyloxycin-namoyloxy)benzoate (11 CPMCB), C35H39O5N, has been determined at room temperature by direct methods. The compound, which exhibits a reentrant nematic phase, crystallizes in the triclinic space group PI, a = 10.368, b = 10.846, c = 16.750 Å, agr = 97.90, b.beta = 100.28, b.gamma = 118.68°, with two molecules in the unit cell. The structure has been refined to R = 0.106, using photographically observed data. The 11 CPMCB molecules pack in a well-imbricated antiparallel arrangement with their alkoxy chains fully extended. The molecular packing in the crystal is discussed with reference to the reentrant behavior of the compound.