Influence of chemical structure on the mesomorphic behaviour of 3,5-disubstituted 1,2,4-oxadiazoles

Study on the thermotropic properties of highly fluorinated 1,2,4-oxadiazolylpyridinium salts and their perspective applications as ionic liquid crystals

“…5a and 8a) is in agreement with previous studies on non ionic liquid crystals, which reported a larger mesophase range for 3-pyridyl compared to 4-pyridyl-1,2,4-oxadiazole systems. 12 The thermochromism phenomenon, observed for all iodide salts, has been characterized confirming the thermally induced yellow-to-red color change. These results open the way to future perspective applications of the studied compounds in optoelectronics.…”

“…8 In the design of non-ionic liquid crystals, the structural features of five-membered heterocycles have been extensively used for the preparation of javelin-, hockey stick-, and bananashaped 9 mesogenic compounds. 10 Moreover, the mesomorphic behaviour of disubstituted 1,2,4-oxadiazoles has recently been studied by Torgova et al 11,12 and the influence of the position of the pyridine substituent on the azole ring has been discussed. 12 In the last decade, besides the synthesis of particularly shaped molecules, another challenge enthralled the interest of liquid crystal designers: the introduction of fluorinated moieties to obtain highly fluorinated molecular organized systems.…”

“…10 Moreover, the mesomorphic behaviour of disubstituted 1,2,4-oxadiazoles has recently been studied by Torgova et al 11,12 and the influence of the position of the pyridine substituent on the azole ring has been discussed. 12 In the last decade, besides the synthesis of particularly shaped molecules, another challenge enthralled the interest of liquid crystal designers: the introduction of fluorinated moieties to obtain highly fluorinated molecular organized systems. 13 In fact, according to the Fluorine Hypothesis, 2 specific electronic or magnetic properties can be tuned by simply introducing a highly fluorinated part or by appropriately choosing the position of the fluorine substituent.…”

Growth of toric domains in mesophases of oxadiazoles

“…In a previous paper [1], hereafter referred as I, we investigated a family of mesomorphic oxadiazoles with asymmetrical molecular structures. The family consisted of oxadiazoles [2][3][4], containing terminal Cl-group and phenyl-cyclohexane fragment together with biphenyl analogues.…”

Fan-shaped, toric and spherulitic textures of mesomorphic oxadiazoles

“…When a family of non symmetrical structures is under investigation, the variety of results is strongly enhanced. Here we discuss the mesomorphic behaviour of some members among a family of non symmetrical compounds, consisting of mesomorphic oxadiazole compounds [4][5][6]. These materials have been developed because their molecular structure with heterocycles as substituents gives smectic and nematic mesophases.…”