Several tetraphenylethenes 2a, 4a–i with lipophilic side chains were synthesized and their mesomorphic properties were investigated. The most promising candidates turned out to be tetrakis[4-(trisalkyloxybenzoyloxy)phenyl]ethenes 4e–i with chain lengths between C7 and C12. Compounds 4 were prepared by a convergent strategy employing a McMurry coupling of 4,4′-dimethoxybenzophenone 1c, followed by demethylation and subsequent esterification of 2c with either 4-decyloxybenzoic acid 3a, 3,4-didecyloxybenzoic acid 3b, or O-alkylated gallic acids 3c–i. Despite the twisting of the central tetraphenylethene moiety compounds 4c–i display hexagonal columnar mesophases according to differential scanning calorimetry (DSC), polarizing microscopy, and X-ray diffraction studies.
No takes yet. Share an insight, caveat, or question.
Schultz et al. (2001) studied this question.