Mesomorphic and electrooptical properties of viologens based on non-symmetric alkyl/polyfluoroalkyl functionalization and on an oxadiazolyl-extended bent core

Abstract

Non-symmetric alkyl/polyfluoroalkyl viologens with electrochromism in the smectic phase and mesomorphism of bent core oxadiazolyl viologens with hampered electrochromism.

Strategies against Nonsense: Oxadiazoles as Translational Readthrough-Inducing Drugs (TRIDs)

“…For instance, 1,2,4-oxadiazoles have lower water solubility than 1,3,4-oxadiazoles because of the reduced hydrogen bond acceptor character of the nitrogen in 1,2,4-oxadiazole ring [43]. Moreover, they have been extensively studied because of their peculiar reactivity [43,48] and possible applications in material chemistry [49,50,51,52,53,54,55] or as bioactive compounds [44,56,57,58].…”

Recent synthetic advances in pyridine-based thermotropic mesogens

“…In addition to this, uid smectic A mesophase was observed when the spacer chain contained less than six carbon atoms and the lateral chains contained more than twelve carbon atoms. Then, Pibiri et al 84 prepared two different types of ionic mesogens comprising nonsymmetrically substituted polyuorinated viologen salts (linear molecules) and bent-shaped symmetrically substituted dialkyloxadiazolyl-bipyridinium salts of bistriimide ion. Most of the linear molecules displayed smectic X mesophase; in some of the molecules, smectic A mesophase was observed in addition to smectic X mesophase.…”

Asymmetric molecular modification of viologens for highly stable electrochromic devices

“…Previously, a few asymmetric viologens have been reported but the correlation between molecular symmetry and EC characterization of viologens has not been systematically investigated. [35][36][37] To prepare asymmetric viologens, two different Nsubstituents of benzyl and heptyl groups were introduced into 4,4 0 -bipyridine, giving 1-benzyl-1 0 -heptyl-4,4 0 -bipyridinium salt (benzyl heptyl viologen, BHV 2+ ). For a comparison, symmetric 1,1 0 -diheptyl-4,4 0 -bipyridinium salt (diheptyl viologens, DHV 2+ ) were used in ECDs.…”