Directed Metalation Route to Ferroelectric Liquid Crystals with a Chiral Fluorenol Core: The Effect of Restricted Rotation on Polar Order

J. Adam McCubbin, Xia Tong, Ruiyao Wang, Yue Zhao, Victor Snieckus*, Robert P. Lemieux

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

63 Citations (Scopus)

Abstract

A new series of smectic C* (SmC*) mesogens containing a chiral (R)-2-octyloxy side chain and either a fluorenone (2a-e) or chiral fluorenol (3a-e) core were synthesized using a combined directed ortho metalation-directed remote metalation strategy. The SmC* phase formed by the fluorenol mesogens is more stable and has a wider temperature range than that formed by the fluorenone mesogens, which may be ascribed to intermolecular hydrogen bonding according to variable-temperature FT-IR measurements. The C11 fluorenol mesogens (R,R)-3d and (S,R)-3d were obtained in diastereomerically pure form and gave reduced polarization (Po) values of +106 and +183 nC/cm2, respectively, at 10 K below the SmA*-SmC* phase transition temperature. The difference in P o values suggests that the chiral fluorenol core contributes to the spontaneous polarization of the SmC* phase. This is ascribed to the bent shape of the fluorenol core, which should restrict its rotation with respect to the side chains in the SmC* phase and favor one orientation of its transverse dipole moment along the polar axis, and to steric coupling of the core to the chiral 2-octyloxy side chain.

Original languageEnglish
Pages (from-to)1161-1167
Number of pages7
JournalJournal of the American Chemical Society
Volume126
Issue number4
DOIs
Publication statusPublished - 4 Feb 2004
Externally publishedYes

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