Forked mesogens

Nitro and Cyano Derivatives Most of the studied compounds are polar forked mesogens with a three-benzene-ring core (41). Table 17 gives the data for the cyano series. The observed mesophases are classical nematic, Sa, and Sc phases. The lamellar thicknesses are higher than the molecular length, so the smectic phases are classified as partially bilayer phases [10, 31, 44, 45]. 

We have recently reported that compound 7a shows a smectic-smectic phase transition associated with the change of the photoluminescent color (Fig. 7) [33]. Compound 7a has a 2,6-diethynylanthracene group as a photoluminescent core. This molecule has fork-like mesogens which consist of tetra(ethylene oxide) and p-(4-/ra .v-pentylcyclohexyl)phenyl moieties. A similar molecular design was previously applied to induce smectic liquid crystallinity for rotaxanes and catenanes [39—41 ]. 

Subclass fiO, combs with one row of side chains. Hardouin and his colleagues call these side-end-fixed polymers . Usually there is a flexible tail beyond the mesogen. Sometimes there are two tails growing out of the mesogen first forked MLCs were synthesized " and later combs with forked tails. Many thermotropic eO PLCs are discussed in Chapter 7 by Simmonds, while lyotropic ones are covered in Chapter 5 by Hall and Tiddy. 

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