Effect of Fluoroalkyl-Substituent in Bistolane-Based Photoluminescent Liquid Crystals on Their Physical Behavior
Shigeyuki Yamada,
Yizhou Wang,
Masato Morita,
Qingzhi Zhang,
David O’Hagan,
Masakazu Nagata,
Tomohiro Agou,
Hiroki Fukumoto,
Toshio Kubota,
Mitsuo Hara,
Tsutomu Konno
Affiliations
Shigeyuki Yamada
Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
Yizhou Wang
Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
Masato Morita
Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
Qingzhi Zhang
School of Chemistry, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, UK
David O’Hagan
School of Chemistry, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, UK
Masakazu Nagata
Department of Quantum Beam Science, Graduate School of Science and Engineering, Ibaraki University, 4-12-1 Naka-narusawa, Hitachi, Ibaraki 316-8511, Japan
Tomohiro Agou
Department of Quantum Beam Science, Graduate School of Science and Engineering, Ibaraki University, 4-12-1 Naka-narusawa, Hitachi, Ibaraki 316-8511, Japan
Hiroki Fukumoto
Department of Quantum Beam Science, Graduate School of Science and Engineering, Ibaraki University, 4-12-1 Naka-narusawa, Hitachi, Ibaraki 316-8511, Japan
Toshio Kubota
Department of Quantum Beam Science, Graduate School of Science and Engineering, Ibaraki University, 4-12-1 Naka-narusawa, Hitachi, Ibaraki 316-8511, Japan
Mitsuo Hara
Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
Tsutomu Konno
Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
Photoluminescent liquid crystals (PLLCs) have attracted significant attention owing to their broad applicability in thermosensing and PL switching. Extensive efforts have been made to develop bistolane-based PLLCs containing flexible units at both molecular terminals, and it has been revealed that their PL behavior can switch with the phase transition between the crystalline and LC phases. Although slight modulation of the flexible unit structure dramatically alters the LC and PL behaviors, few studies into the modification of the flexible units have been conducted. With the aim of achieving dynamic changes in their physical behaviors, we developed a family of bistolane derivatives containing a simple alkyl or a fluoroalkyl flexible chain and carried out a detailed systematic evaluation of their physical behaviors. Bistolanes containing a simple alkyl chain showed a nematic LC phase, whereas switching the flexible chain in the bistolane to a fluoroalkyl moiety significantly altered the LC phase to generate a smectic phase. The fluoroalkyl-containing bistolanes displayed a stronger deep blue PL than their corresponding non-fluorinated counterparts, even in the crystalline phase, which was attributed to the construction of rigid molecular aggregates through intermolecular F···H and F···F interactions to suppress non-radiative deactivation.
