Biphenylyl-1, 2, 4-oxadiazole based liquid crystals – synthesis, mesomorphism, effect of lateral monofluorination. Issue 15 (8th December 2019)

• Record Type: Journal Article
• Authors: Fouad, Farid S.; Ness, Todd; Wang, Kunlun; Ruth, Christopher E.; Britton, Sonia; Twieg, Robert J.
• Is Part Of: Liquid crystals. Volume 46:Issue 15(2019)
• Page Start: 2281
• Page End: 2290
• Publication Date: 2019-12-08
• Subjects: Heteroaromaic liquid crystals -- wide nematic -- low temperature nematic -- 1, 2, 4-oxadiaxoles -- biphenyl -- fluorinated liquid crystals; Liquid crystals -- Periodicals; 548.905
• DOI: 10.1080/02678292.2019.1623335
• Languages: English
• ISSNs: 0267-8292

Abstract

ABSTRACT: Aiming at developing a new type of materials for functional applications, three series of new compounds were prepared, 3-(biphenylyl)-1, 2, 4-oxadiazoles, Series I; laterally mono-fluorinated 3-(biphenylyl)-1, 2, 4-oxadiazoles, Series II; and 5-(biphenylyl)-1, 2, 4-oxadiazoles, Series III. Liquid crystalline properties of these compounds were studied using differential scanning calorimetry and polarizing optical microscopy. Ten of the thirteen compounds in Series I are mesogenic forming either N or SmA phases depending on the length-to-width molecular ratio. Mesogens of the positional isomers, Series III are both N and SmA. Monofluorination of the biphenylyl group at either the central or the terminal phenylene rings, Series III, resulted in the formation of nematic mesogens with low phase transition temperatures and broad nematic phase range. Graphical Abstract: