Polymorphism and Initial Structure Modelling of a New Mesogen 9OSBch

M. Kosyla, b, W. Zającc, M.D. Ossowska-Chruściela and J. Chruściela aSiedlce University of Natural Sciences and Humanities, Institute of Chemistry, 3-go Maja 54, 08-110 Siedlce, Poland bJoint Institute for Nuclear Research, Laboratory of Neutron Physics, F. Joliot-Curie 6, 141 Dubna, Russian Federation cThe Henryk Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, E. Radzikowskiego 152, 31-342 Kraków, Poland

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We report the properties of a novel mesogen with high temperature cholesteric mesophase, which belongs to an unexplored as yet series of cholesteric esters. This compound is cholesteryl 4-(4-nonyloxy-benzo-ylthio) benzoate (C9H19OC6H4COSC6H4COOch, where ch = cholesteryl), hereafter named 9OSBch. The chemical structure and purity of 9OSBch was established by 1H NMR, 13C NMR and FT-IR spectroscopy, and its mesomorphism was characterised by differential scanning calorimetry, polarizing optical microscopy, and transmitted light intensity. Differential scanning calorimetry measurements showed that substance is stable up to 270°C and partially decomposes above this temperature. Observation under polarizing optical microscope revealed oily streak texture of cholesteric phase (Ch). The chemical structure of an isolated molecule was optimized by the density functional theory method. Energetically most favourable configuration is that of hockey stick geometry. At the same time this is the conformation best suited for the formation of highly ordered condensed phases.

DOI: 10.12693/APhysPolA.124.959 PACS numbers: 61.30.Eb, 64.70.M-