Zum Konformationsverhalten substituierter Benzoesäurephenylester - Molekül- und Kristallstruktur der nematogenen Verbindung 4-n-Pentoxybenzoesäure-4′-(ß-cyanethyl)-phenylester

On the Conformational Behaviour of Substituted Phenylbenzoates - Molecular and Crystal Structure of the Nematogenic Compound 4′-(ß-Cyanoethyl)-phenyl-4-n-pentoxybenzoate The title compound crystallizes in the monoclinic space group P2₁/n with a = 1567.6(2) pm, b = 915.5(1) pm, c = 1459.1(1) pm, β = 115.30(1)°, and four molecules per unit cell. The structure has been solved by direct methods and refined to R = 0.104. The molecules adopt a markedly stretched form and show a parallel arrangement of their long axes in the crystal lattice. The molecular and crystal structure is discussed in relation to the mesomorphic behaviour of the compound. A theoretical conformational analysis has been performed for the isolated phenylbenzoate molecule using the EPEN/2 method, its results are compared with the experimental torsion angles in a series of substituted phenylbenzoates.