The synthesis, mesomorphic and dielectric investigation of new unsymmetrical bent-core mesogens derived from 3-hydroxybenzoic acid


Ocak H., Ahlatcıoğlu Özerol E., Çelikel F. Ç. , Okutan M., Bilgin Eran B.

Chemical Papers, vol.74, no.11, pp.3899-3911, 2020 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 74 Issue: 11
  • Publication Date: 2020
  • Doi Number: 10.1007/s11696-020-01203-4
  • Journal Name: Chemical Papers
  • Journal Indexes: Science Citation Index Expanded, Scopus, Chemical Abstracts Core
  • Page Numbers: pp.3899-3911
  • Keywords: Liquid crystals, Bent-core compounds, 3-Hydroxybenzoic acid derivatives, Columnar mesophase, Dielectric measurement, SHAPED LIQUID-CRYSTALS, CARBOXYL CONNECTING GROUPS, SMECTIC-A PHASE, HOMOLOGOUS SERIES, LATERAL SUBSTITUENTS, MESOPHASE BEHAVIOR, LINKAGE GROUPS, POLAR ORDER, TRANSITION, MOLECULES

Abstract

© 2020, Institute of Chemistry, Slovak Academy of Sciences.Abstract: The synthesis, mesomorphic and dielectric investigation of new unsymmetrical bent-core mesogens derived from 3-hydroxybenzoic acid central core with linked two rodlike units carrying (S)-3,7-dimethyloctyloxy group and an n-alkyloxy chain at both terminals are presented. The liquid crystalline properties of the new unsymmetrical bent-core materials have been investigated by polarizing optical microscopy and differential scanning calorimetry. New compounds with the reversed ester linking unit exhibit a monotropic or enantiotropic columnar mesophase at lower temperatures as compared to analogs with a straight chain depending on the presence of the branched (S)-3,7-dimethyloctyloxy terminal chain. Dielectric measurements for one of the bent-core mesogens, 3-[[4-[[4-(octyloxy)benzoyl]oxy]benzoyl]oxy]benzoic acid 4-[[4-((S)-3,7-dimethyloctyloxy)phenoxy]carbonyl]phenyl ester (OBDPE), have been carried out on the angular frequency range from 25.12 to 50265k rad/s at different temperatures. Thanks to dielectric measurements, real and imaginary dielectric constant, conductivity mechanism and dielectric relaxation mechanism of OBDPE were obtained. Graphic abstract: [Figure not available: see fulltext.].