67399-89-7Relevant academic research and scientific papers
4-Methylresorcinol based bent-core liquid crystals with azobenzene wings-a new class of compounds with dark conglomerate phases
Alaasar, Mohamed,Prehm, Marko,Brautzsch, Marcel,Tschierske, Carsten
, p. 5487 - 5501 (2014)
Stochastic achiral symmetry breaking in soft matter systems, leading to conglomerates of macroscopically chiral domains (so-called dark conglomerate = DC phases) is of contemporary interest from a fundamental scientific point of view as well as for numero
Synthesis and liquid crystal property of new fluoro coumarin carboxylates
Mahadevan, Kittappa M.,Harishkumar, Hosanagara N.,Masagalli, Jagadeesh N.,Srinivasa, Hosapalya T.
, p. 20 - 35 (2013/08/24)
New liquid crystalline 4-alkoxyphenyl-coumarin-3-carboxylates 6a-e, 7a-g, 8a-e, and 9a-e were prepared by reacting various coumarin-3-carboxylic acids 5a-d with 4-(alkoxy) phenols 4a-g in the presence of 1(3-dimethylaminopropyl-3- ethylcarbodiimide/dimethyl amino pyridine (EDCI/DMAP) as a coupling agent. The structures of the new coumarin derivatives were confirmed by spectral analysis and the liquid crystalline property was established by polarizing optical microscope and by differential scanning calorimetric techniques. The diethyl amine and morpholine were taken as electron-donating and -CF3 as electron-withdrawing groups at the seventh position of the coumarin-3-carboxylic acids to check the mesomorphic property in all new 4-alkoxyphenyl-coumarin-3- carboxylates. Among them, only 4-alkoxyphenyl-7-triflouromethyl-coumarin-3- carboxylates 7a-g exhibited liquid crystalline SmA phase.
Reentrant SmCPA phases: Unusual polymorphism variant SmA-SmCSPA-Colob-SmCSPA observed in new bent-core mesogens
Shreenivasa Murthy,Bodyagin,Diele,Baumeister,Pelzl,Weissflog
, p. 1634 - 1643 (2007/10/03)
A new homologous series of achiral five-ring bent-core mesogens is presented. The mesophase behaviour has been studied by polarizing microscopy, differential scanning calorimetry, X-ray diffraction and electro-optical measurements. The homologues with shorter terminal chains (C8, C 12) form an SmCPA phase, homologues with longer chains (C14, C16, C18) show liquid-crystalline tetramorphism with a sequence SmA-SmCSPA-Col ob-SmCSPA. The SmCPA phases are structurally identical and differ only in the mechanism of polar switching. The switching of the high-temperature SmCSPA phase takes place through the collective rotation of the molecules around their long axes whereas in the reentrant SmCSPA phase the switching is based on the director rotation around the tilt cone. By the application of an electric field the Colob phase can be irreversibly transformed to an SmCP A phase. In a limited temperature range the SmA phase shows a reversible field-induced transition into the SmCSPF phase. The electro-optical response of the mesophases is discussed on the basis of the structural features of these phases. The Royal Society of Chemistry 2006.
