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Optically Active Micellar-Cubic Liquid Crystals from Quasi-Racemic Octahedral Metallomesogens.
Shiho Akiba1, Kozue Nishimoto2, Hidetaka Yuge2
1Department of Chemistry, College of Humanities & Sciences, Nihon University, Setagaya-ku, Tokyo, Japan.
Macromolecular Rapid Communications
|August 17, 2025
Summary
Octahedral metallomesogens with chiral centers form a unique micellar cubic liquid-crystal phase. Mixing enantiomers creates novel chiroptical materials, suggesting new design strategies.
Area of Science:
- Supramolecular chemistry
- Materials science
- Liquid crystals
Background:
- Octahedral metal complexes are explored for liquid crystal properties.
- Chirality in metallomesogens influences self-assembly and phase behavior.
Purpose of the Study:
- To investigate the liquid crystal phases of racemic and enantiopure octahedral metal complexes.
- To explore the role of chiral interactions in driving supramolecular assembly.
- To develop novel chiroptical materials through enantiomer mixing.
Main Methods:
- Synthesis of octahedral metal complexes with varying alkyl chain lengths.
- X-ray diffraction to characterize liquid crystal phases (micellar cubic and hexagonal-columnar).
- Preparation and characterization of quasi-racemic mixtures.
- Vibrational circular dichroism spectroscopy to analyze chiral interactions.
Main Results:
- Racemic M-Cn complexes exhibit a micellar cubic (CubM) phase (space group Im3m) with J-type aggregates.
- Enantiopure Δ- and Λ-M-Cn complexes form hexagonal-columnar phases with helical stacking.
- Quasi-racemic mixtures display CubM phases similar to pure racemates.
- Novel vibrational circular dichroism signals observed in quasi-racemates due to close Δ and Λ packing.
Conclusions:
- Chiral interactions are crucial for the supramolecular assembly of these metallomesogens.
- Mixing enantiomers in a quasi-mirror image relationship is a viable strategy for creating new chiroptical materials.
- The study introduces a novel approach to designing advanced functional materials.
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