Columnar liquid crystals based on amino-1,3,4-thiadiazole derivatives

Synthesis, Phase Behavior and Computational Simulations of a Pyridyl-Based Liquid Crystal System

“…Due to their beneficial capacity to impart lateral and/or longitudinal dipoles, together with variations in their molecular geometries, which are reflected in their optical and electrical behaviors, heterocyclic-based LC materials have been of great interest to many researchers [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Pyridine exhibits a dipole moment of 2.19 D, which is about fivehundredths of that of a cyano group (~4.0 D) [25]; consequently, it influences the stability of the mesophase when it is utilized as a moiety within the mesogens [25][26][27][28][29][30].…”

Effect of regioisomerism on the self-assembly and photophysical behavior of 1,3,4-thiadiazole-based polycatenars

“…26 Reports on their sulfur analogues, i.e. Calamitic LCs, 28 banana shaped LCs, 29 hydrogen bonded LCs, 30 and polymeric LCs 31 based on 1,3,4-thiadiazole are reported. It is expected that, substitution of oxygen with sulfur increases the dipole moments, packing of molecules, viscocity, melting and clearing temperatures.…”

“…23c,27 In addition to this notion, partly the synthetic difficulty, coupled with low yields, has curtailed attempts in this direction. Calamitic LCs, 28 banana-shaped LCs, 29 hydrogen-bonded LCs 30 and polymeric LCs 31 based on 1,3,4thiadiazole have been reported. Very recently, a few polycatenar LCs 26,32 and star-shaped mesogens 33a stabilizing a columnar phase have been reported.…”

Columnar self-assembly of star-shaped luminescent oxadiazole and thiadiazole derivatives

“…35a These alkoxy esters (5a-d) obtained by Williamson's protocol were converted to their respective hydrazides (4a-d) by treating with hydrazine hydrate and with ethanol or n-butanol as the solvent. 20k Hydrazides 4a-d were then refluxed with trimesic acid chloride in THF in the presence of triethylamine to obtain tri-N-benzoylbenzohydrazides 3a-d. 19a Compounds 3a-d were subjected to POCl 3 mediated dehydrocyclization to obtain trioxadiazoles 1a-d. 19a Similarly, compounds 3a-d on refluxing with Lawesson's reagent 35b in toluene yielded corresponding trithiadiazoles 2a-d. 31 The use of P 2 S 5 did not provide good yields because of the incomplete reactions. The structures of all the intermediates and target molecules were confirmed using 1 H NMR, 13 C NMR, and IR spectroscopy as well as with ESI-HRMS or MALDI-TOF analysis.…”

“…This is partly attributed to the difficult synthesis and low yields. Very few reports on calamitic mesogens, 29 banana mesogens, 30 hydrogenbonded LCs, 31 polymerics, 32 and polycatenars 26,33 based on 1,3,4thiadiazole are found in previous studies. Recently, there are few reports of bent molecules stabilizing smectic and nematic phases 34a and star shaped molecules bearing 1,3,4-thiadiazole unit stabilizing the Col phase.…”