H. Hartung, A. Stettler, W. Weissflog
Aug 10, 2000
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0
Influential Citations
7
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Journal
Journal of Molecular Structure
Abstract
Abstract The crystal and molecular structures of hexyloxy (3a) and heptyloxy homologues (3b) of mesogenic 4,6-dichloro-1,3-phenylene bis[4-(4-n-alkyloxy-phenyliminomethyl)benzoates] have been determined by X-ray analyses. Both compounds crystallize in the triclinic space group P 1 with two molecules in unit cells of following dimensions. 3a: a=8.340(2), b=13.143(4) and c=19.364(6) A ; α=96.36(4), β=93.33(4) and γ=103.07(1)°; 3b: a=8.738(2), b=15.850(4) and c=17.618(5) A ; α=115.73(2), β=90.82(2) and γ=95.49(2)°. The structures were solved by direct methods and refined on F2 to R values of R1=0.046 (3a) and 0.094 (3b). The molecular structures of 3a and 3b are discussed in detail, especially in view of the correlation between molecular conformation (banana- or rod-shaped molecules) and liquid crystalline behaviour (observed mesophases). It can be shown for 3a and 3b that the molecules are not strongly bent and not so far from the rod-like shape. Crystal packing of the mesogens is characterized by a parallel arrangement of the strongly interlocked molecules.