Alkoxylation in achiral calamitic liquid crystals

Halogenation in Achiral Calamitic Liquid Crystals. II Terminal and Linking Substitutions

“…Similar trends have been found for other sulphur-containing groups [44]. The introduction of the oxygen atom into the halogenated groups usually enhances their thermal efficiency (compounds 3-3, 3-27; 3-4, 3-25) which is supported by the findings for other oxygen-containing groups [45]. The additional alkoxy or alkyl groups, introduced between the terminal halogenated group and molecular core, can increase (compounds 3-1, 3-8; 3-2, 3-11; 3-6, 3-25, 3-31; 3-7, 3-27; 3-13, 3-17) and lower (compounds 3-12, 3-16) the clearing points.…”

Pyrimidine as a Structural Fragment in Calamitic Liquid Crystals

“…However, it is not so easy because the order of increasing the polarizability of the molecular fragments under consideration (see Section 2) is not supported by the order of increasing the optical anisotropy in some cases (see for example, compounds 2-1, 2-2; 3-1-3-4). This situation needs more careful consideration including the direct measurements of the optical anisotropy and the study of the molecular packing of the discussed compounds [265,266]. Similar trends have been observed for other pyrimidine derivatives [98,100,109,120,128,129,137,139,178,221,223].…”

The Influence of Oxygen on Mesomorphic Behavior of Benzylidene Anilines—The Effect of End Chain

“…While moving along each column, except the middle homologous (n ¼ 4 and 5) members, all other lower and higher homologous series show a non-liquid-crystalline nature irrespective of the position of oxygen. It may be claimed that the repulsion between neighboring molecules with increasing intermolecular separation may responsible for these suppressed mesomorphic properties [12].…”