Core smectogens

Usually the core system in smectogens contains a linking group positioned either between two ring units or between a ring and an aliphatic chain. The linking group has been shown to have marked effects on... 

Tricatenars Several other mesogens of this type have been synthesized. They have a three-benzene-ring core and display the classical mesomorphic properties of rodlike mesogens. For instance, compounds 27 [5] and 28 [5,31] are smectogenic C and ne-matogenic, but when the alkyloxy chain is moved from meta to ortho position, the compound becomes only nematogenic. 

Smectogenic molecules, which are typically built from semiflexible rodlike cores of phenyl rings linked together by more or less flexible links such as COO, —CH = N —, —CH - CH —, CH2 — CH2 — and one or two paraffinic chains whose length is usually 6 to 20 carbon atoms grafted in para positions. Examples for smectogens are seen in Figure 1.5. 

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