New isothiocyanatotolane liquid crystals with terminal but-3-enyl substitute |
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| Authors: | Juanli Li Jian Li Minggang Hu Zenghui Peng Lu Zhang |
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| Institution: | 1. State Key Laboratory of Fluorine &2. Nitrogen Chemicals, Xi’an, P. R. China;3. Optical and Electrical Material Center, Xi’an Modern Chemistry Research Institute, Xi’an, P. R. China;4. State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, P. R. China |
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| Abstract: | Four kinds of new but-3-enyl-based isothiocyanate liquid crystals composed of tolane core and but-3-enyl terminal group (A1–A4) were synthesised via seven step reactions based on 2-(4-bromophenethyl)-1,3-dioxolane, and four n-butyl analogues B1–B4 as comparison structures were also prepared. The mesomorphic properties and physical properties of the compounds were investigated. Single fluorinated compounds A2 and A3 exhibit monotropic nematic phase, and they have lower melting enthalpy and higher clearing points than those of the comparison compounds B2 and B3. The non-fluoro-substituted compound A1 and difluorinated compound A4 exhibit no nematic phase. Replacement of n-butyl chain by but-3-enyl as terminal group is enabled to increase birefringence (Δn ~ 0.394–0.430) and reduce rotational viscosity. These isothiocyanatotolanes with terminal but-3-enyl substitution have potential application for high birefringence mixtures. |
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| Keywords: | Isothiocyanate monotropic nematic phase birefringence rotational viscosity |
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