Drushlyak T. New chiral esters and 1-aryl-spiro[2,5]octane-4-ones in liquid crystalline systems

Investigation objects: chiral unsaturated ketones, 2-аrylidene derivatives of 3(R)-methyl-6(R)-isopropylcyclohexanone, intermediate ketols and 1-aryl-spiro[2,5]octane-4-ones. Purpose: development of the synthetic approaches for the new 2- аrylidene derivatives of 3(R)-methyl-6(R)-isopropylcyclohexanones (2-arylidene-p-menthane-3-ones) and products of their cyclopropanation, connection ascertainment between their molecular structure and properties of liquid crystalline systems with these substances, and also molecular model development for twisting in induced cholesterics. Methods: organic synthesis, thin-layer- and high perfomance liquid chromatography, NMR 1H and 13C, IR, mass-spectrometry, X-ray analysis, polarizing microscopy, electro-optics of liquid crystals, semiempirical quantum chemistry methods AM1 and PM3. Structural factors responsible for ?,?-unsaturated ketones and row of spiroproducts twisting properties in the nematic liquid crystal medium have been estimated. Trans-trans-1(S)-(4Х-phenyl)-5(R)-іsо-propyl-8(R)-methyl-3(R)-spiro[2,5]-octanones are the most perspective for the highly effective chiral dopants for nematic liquid crystals design. Prospects of these compounds for their use at the highly photo-stable cholesteric liquid crystal compositions with selective visible light reflection for composites with low voltage control have been shown. Some of synthesized esters in SmC system show short switching time (in microseconds). Developed molecular model for supramolecular helix formation in nematics doped with chiral dopants may be used in off-experiment screening for perspective structures. further investigations on chiral organic compounds spatial structure influence on mesomorphic properties and behaviour in the liquid crystalline systems as well as design of the liquid crystal compositions for the optoelectronics purposes. The field is Organic Chemistry, material researches