Alkyl substituted monocyclic 1,2,3-triazines and their 1-and %oxides have been synthesized ; catalytic reduction (on Pd-C) of the triazines afforded their 2,5-dihydro compounds.ALTHOUGH the chemical and physical properties of 1,2,3triazines have been of interest and condensed 1,2,3-triazines have been widely investigated, little is. known concerning the monocyclic 1,2,3-triazines (1) .l The preparation of compounds (1) has been limited to cases in which R1 = R2 = R3 = alkyl, aryl, or halogen, or a group (alkylamino, alkoxy, etc.) introduced by nucleophilic substitution of halogen. 9 2t
Several new classes of low polar, low viscous and optically weak anisotropic two-and three-ring fluorinated liquid crystals (LCs) with ether terminal groups are presented. Their material properties are investigated and compared with those of fluorinated LCs with alkenyl terminal groups. The 4-fluorophenylbicyclohexane ethers were found to exhibit dielectric anisotropies AE which are similar to those of the corresponding alkenyls with 1-propenyl and 3-pentenyl group, whereas the alkenyls with 4-pentenyl group exhibit considerably lower AE-ValUeS. The optical and dielectric anisotropies of difluoroethers with odd numbers n of the methylene groups separating the ether oxygen from the rigid cores of the molecules are comparable, whereas compounds with odd n's were found to exhibit lower viscoelastic ratios Y,/K and therefore shorter response times in twisted nematic liquid crystal displays (TNLCDs) than their even counterparts.In mixtures designed for thin film transistor (TFT)-addressed TN-LCDs the new compounds are shown to exhibit very large voltage holding ratios HR > 98% which are maintained after extended exposure to high temperatures (80°C) andlor high light intensities.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.