TGBA and TGBC phases in some chiral tolan derivatives

H. Nguyen , A. Bouchta , L. Navailles , P. Barois , N. Isaert , R. Twieg , A. Maaroufi , C. Destrade

Three chiral compounds (n=10, 11, 12) belonging to the optically active series : 3-fluoro-4-[(R) or (S)-1-methylheptyloxy]-4'-(4$''$-alkoxy-2$''$, 3$''$-difluorobenzoyloxy) tolans (nF2BTFO1M7) have been synthesized. The helical SA* phase or TGBA phase is found in the decyloxy derivative. The most interesting compound is obtained with n=11. It displays, for the first time, two TGB phases (TGBA and TGBC phases). The nature of these helical smectic phases is confirmed by different studies : optical observation, DSC, contact method, mixtures, X-ray diffraction and helical pitch measurements. the electrooptical properties of the SC* phase have also been studied.

Domaines: Articles anciens

H. Nguyen, A. Bouchta, L. Navailles, P. Barois, N. Isaert, et al.. TGBA and TGBC phases in some chiral tolan derivatives. Journal de Physique II, 1992, 2 (10), pp.1889-1906. ⟨10.1051/jp2:1992242⟩. ⟨jpa-00247776⟩