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Abstract
The crystal and molecular structure of the title compound were determined: a = 14.375(3), b = 11.534(3), c = 7.972(2) Å, α = 71.694(5), β = 79.125(5), γ - 74.861(5)°; space group PI. Refinement including all of the observed reflections (3145) leads to R = 0.086 (Rw= 0.074).
The molecular form in the crystalline state is fully extended in agreement with the suggestion by Birner et al. (Mol. Cryst. Liq. Cryst., 80, 11 (1982)), based on a NDDO-semiempirical calculation.
Whereas for the molecular form in the nematic liquid crystalline state a slightly parallel arrangement (∼ 60°) of the dipole moment components perpendicular to the long axis is proposed, in the crystalline state these components are at an angle ∼ 120° to each other, and somewhat antiparallel.
Preceding the melting point by approximately 10 degrees, DSC and thermal microscopy signals were observed; these depend eventually on solid-state polymorphism.