Chiral Octahedral Metallomesogens with Δ/Λ Core Chirality: Extending Wallach's Rule from Crystals to Liquid Crystals
5 affiliations
- 1Department of Chemistry, College of Humanities & Sciences
- 2Nihon University
- 3Faculty of Engineering and Design
- 4Kagawa University
- 5School of Frontier Engineering, Kitasato University, 1-15-1 Kitazato, Sagamihara, Kanagawa, Japan, 252-0373
Abstract
Chirality often induces marked structural changes in liquid crystals (LCs) and can even induce new phases. Where chirality resides in a mesogen is thus a fundamental question, but because mesogens favor planar structures, the effect of chirality at the molecular center (core chirality) on their assemblies has remained poorly understood. This Account explores this question with the octahedral tris(β-diketonato) family M-Cn (M = Ru, Ir), whose Δ/Λ configuration proves to be a decisive design element. Enantiopure Ru-C8 builds helical hexagonal columns, whereas its racemate assembles ΔΛ-alternating paired columns, and longer alkyl chains switch the system to a micellar cubic phase. Strikingly, the racemate is the more stable form: Wallach’s rule, known for crystals, also governs the LC state. This Δ–Λ recognition can be harnessed: pairing Δ-Ru-Cn with Λ-Ir-Cn gives quasi-racemic LCs with emergent chiroptical properties, such as stereoselectively enhanced vibrational circular dichroism.
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BibTeX
@misc{yoshida2026chiral,
title = {{Chiral Octahedral Metallomesogens with Δ/Λ Core Chirality: Extending Wallach's Rule from Crystals to Liquid Crystals}},
author = {Jun Yoshida and Mitsuo Hara and Go Watanabe},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15010803/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010803/v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Chiral Octahedral Metallomesogens with Δ/Λ Core Chirality: Extending Wallach's Rule from Crystals to Liquid Crystals
AU - Jun Yoshida
AU - Mitsuo Hara
AU - Go Watanabe
PY - 2026
DA - 2026/10/21
PB - ChemRxiv
DO - 10.26434/chemrxiv.15010803/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010803/v1
AB - Chirality often induces marked structural changes in liquid crystals (LCs) and can even induce new phases. Where chirality resides in a mesogen is thus a fundamental question, but because mesogens favor planar structures, the effect of chirality at the molecular center (core chirality) on their assemblies has remained poorly understood. This Account explores this question with the octahedral tris(β-diketonato) family M-Cn (M = Ru, Ir), whose Δ/Λ configuration proves to be a decisive design element. Enantiopure Ru-C8 builds helical hexagonal columns, whereas its racemate assembles ΔΛ-alternating paired columns, and longer alkyl chains switch the system to a micellar cubic phase. Strikingly, the racemate is the more stable form: Wallach’s rule, known for crystals, also governs the LC state. This Δ–Λ recognition can be harnessed: pairing Δ-Ru-Cn with Λ-Ir-Cn gives quasi-racemic LCs with emergent chiroptical properties, such as stereoselectively enhanced vibrational circular dichroism.
ER -