Document

Synthesis and mesomorphism of a novel series of calamitic fluorinated organosiloxane liquid crystals.

Other titles
تحضير ودراسة الحالة البينية لسلسلة جديدة من البلورات السائلة الكالاميتية المفلورة المحتوية على مجموعة من السيلوكسان العضوي
Publisher
Sultan Qaboos University.
Gregorian
2022
Language
English
English abstract
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.
Arabic abstract
تغطي هذه الدراسة تحضير ودراسة الحالة البينية الميسومورفيكية لأربعة مركبات بلورية سائلة كالاميتية مفلورة ومحتوية على مجموعة من السيلوكسان العضوي باستخدام تفاعلات وبروتوكولات مثبتة . تحتوي هذه البلورات السائلة الأربعة على سلسلة جانبية غير متناظرة بها سبع كربونات ذت التكوين المطلق (R).
Category
Theses and Dissertations

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