The Crystal and Molecular Structure and Thermal Properties of the Mesogenic 4″-Nitrophenyl-4-(4′-n-hexyloxybenzoyloxy)-cinnamate; Phase Behavior of Related Compounds

Abstract

The crystal and molecular structure of the mesogenic 4″-nitrophenyl-4-(4′-n-hexyloxybenzoyloxy)-cinnamate, RNO₂, has been determined by X-ray diffraction method. Crystal data: triclinic, space group P1, a = 13.570(8) Å, b = 10.885(7) Å, c = 9.805(7) Å, α = 105.34(3)°, β = 101.17(3)°, γ = 106.84(3)°, Z = 2. The molecule occurs in its fully extended form, the three phenyl rings are twisted against each other. All molecules lie parallel, the terminal NO₂-groups related to the center of symmetry have a comparatively short NO₂-NO′₂ distance, namely, N-N′ = 3.04(1) °. The thermal behavior of the title compound and related compounds was investigated. The influence of different substituents, Br, CN and a lateral OCH₃ group, on the temperature range of the liquid crystalline phase is discussed.

Key Words:

• crystalline state
• molecular conformation
• thermal properties
• disubstituted cinnamates