1020538-75-3Relevant academic research and scientific papers
Effect of heteroatom exchange (S/Se) in the mesomorphism and physical properties of benzochalcogenodiazole-based liquid crystals
Regis, Elias,Aguiar, Leonardo de O.,Tuzimoto, Patricia,Girotto, Edivandro,Frizon, Tiago E.,Dal Bó, Alexandre G.,Zapp, Eduardo,Marra, Raphael,Gallardo, Hugo,Vieira, André A.
, p. 109 - 116 (2018/05/07)
In order to investigate the effect on the structure-property relationship by the exchange of sulfur atom by selenium, a new series of fluorescent calamitic liquid crystals based on 4,7-disubstituted-2,1,3-benzoselenadiazole was successfully synthesized and characterized. The mesomorphic properties were studied by differential scanning calorimetry, polarized optical microscopy and X-ray diffraction. Thermal properties have evidenced the influence of changing sulfur by selenium atom in the formation of liquid crystalline phases and mesomorphism range. Photophysical studies were performed in chloroform solution, where these compounds displayed strong orange luminescent under UV light, with relevant quantum yields (ΦF = 0.14–0.16) and greater solvatochromic dependence. Electrochemical studies showed oxidation and reduction patterns similar to 2,1,3-benzothiadiazoles analogues, however presenting lower band gap.
Rigid-flexible block molecules based on a laterally extended aromatic segment: Hierarchical assembly into single fibers, flat ribbons, and twisted ribbons
Lee, Eunji,Huang, Zhegang,Ryu, Ja-Hyoung,Lee, Myongsoo
experimental part, p. 6957 - 6966 (2009/07/18)
Self-assembling rigid-flexible block molecules consisting of a laterally extended aromatic segment and different lengths of hydrophilic coils were synthesized and characterized. The block molecule based on a long polyethylene oxide) coil (1), in the melt state, shows an unidentified columnar structure, whereas the molecule with a shorter poly(ethylene oxide) coil (2) self-organizes into an oblique columnar structure. Further decrease in the poly(ethylene oxide) coil length as in the case of 3, on heating, induces a rectangular columnar structure in addition to an oblique columnar mesophase. In diethyl ether, 1 and 2 were observed to self-assemble into uniform nanofibers with bilayer packing. Remarkably, these elementary fibers were observed to further aggregate in a lateral way to form well-defined flat ribbons (1) and twisted ribbons (2) with solvent exchange of diethyl ether into methanol. Furthermore, the ribbons formed in methanol dissociated into elementary fibers in response to the addition of aromatic guest molecules. This transformation between ribbons and single fibers in response to the addition of guest molecules is attributed to the intercalation of aromatic substrates within the rigid segments and subsequent loosening of the aromatic stacking interactions. These results demonstrate that the introduction of a laterally extended aromatic segment into an amphiphilic molecular architecture can lead to the hierarchical formation from elementary fibers of nanoribbons with a tunable twist through controlled lateral interactions between aromatic segments.
Luminescent 2,1,3-benzothiadiazole-based liquid crystalline compounds
Vieira, André A.,Cristiano, Rodrigo,Bortoluzzi, Adailton J.,Gallardo, Hugo
, p. 364 - 371 (2008/09/18)
A series of fluorescent 2,1,3-benzothiadiazole-based liquid crystals bearing a π-extended aromatic portion through C{triple bond, long}C triple bond was synthesized and characterized. The X-ray structure of the rigid core was performed. The mesomorphism a
