الملخص الإنجليزي
This study covers the synthesis and mesomorphic analysis of four novel calamitic
fluorinated chiral organosiloxane liquid crystals utilizing confirmed procedures and
protocols. All four mesogenic liquid crystals (6a, 6b, 6c & 6d) consist of a chiral side
chain with seven carbons with an (R) absolute configuration, while the other side chain is
made up of an organosiloxane group that differs in the length of the hydrocarbon chain
(C-7, C-8, C-10 & C-11) respectively. The general name of the series is (R)-heptan-2-yl
4'-((3-fluoro-4-((n-(1,1,1,3,5,5,5-heptamethyltrisiloxan-3-yl)alkenyl)oxy)benzoyl)oxy)-
3'-nitro-[1,1'-biphenyl]-4-carboxylate, where n = 7, 8, 10, 11 for compounds 6a, 6b, 6c &
6d, respectively. The percent yield for the four synthesized liquid crystal compounds was:
30.6, 25.3, 34 & 27.2% for 6a, 6b, 6c & 6d, respectively.
The structures of intermediates and final products were confirmed by 1
H-NMR and 13C NMR spectroscopy. The phase transition behavior of the liquid crystals was performed by
using polarized optical microscopy (POM). All liquid crystal products were found to be
ferroelectric liquid crystals as they respond to an applied external electric field. They
exhibit a SmC* phase at room temperature with a relatively narrow transition window,
and the phase transitions to SmA* as the temperature is increased.
