measuring-magnetically-tuned-ferroelectric-polarization-liquid

Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals

Materials showing coupling phenomena between magnetism and (ferro)electricity, i.e., magnetoelectric effects, have attracted a great deal of attention due ...

Osaka University

The supramolecular chirality of aggregates consisting of achiral trans-bis(salicylaldiminato)Ni complex 1 bearing long alkyl chains can be generated and controlled precisely in a chiral nematic liquid-crystalline (LC) solvent, whereas the complex naturally forms achiral gel fibers in achiral nematic LC solvents and crystals in nonmesogenic solvents. The direction and intensity of the helicity of the gel fibers of 1 in the LC gel state can be adjusted by means of the nature of the helical twisting and the concentration of the chiral dopants. Helicity control was precisely detected in the circular dichroism (CD) spectra of LC gels and by direct SEM observation of the dried gel fibers. XRD analysis revealed that the flexibility of the herringbone-based lamellar alignment of this complex is the key to the LC-specific gelation and helicity control of the gel fibers.

Helicity Control of Supramolecular Gel Fibers Consisting of an Achiral Ni Complex in a Chiral Nematic Solvent.

We synthesized new chiral all-organic liquid crystalline (LC) compounds with nitroxide (NO) and hydroxy (OH) groups, which form intermolecular hydrogen bonds between the NO and OH groups. The LC compounds show hexagonal columnar phases at room temperature, which solidify as LC glasses at low temperature. The experimental magnetic susceptibility of each of the compounds in the LC and isotropic phases is larger than that theoretically estimated on the simple assumption about the amount of the spins, whereas it accords with the theoretical one in the LC glass state. It is called magneto-LC effects. The difference between experimental and theoretical magnetic susceptibilities gradually increases as temperature increases through the LC glass state-to-LC phase transition. It suggests that molecular mobility is one of the origins of the magneto-LC effects.

Article	Year
Helicity Control of Supramolecular Gel Fibers Consisting of an Achiral Ni Complex in a Chiral Nematic Solvent. Chemistry (Weinheim an der Bergstrasse, Germany)\| PubMed ID: 29863759	2018
Molecular Mobility Effect on Magnetic Interactions in All-Organic Paramagnetic Liquid Crystal with Nitroxide Radical as a Hydrogen-Bonding Acceptor. The journal of physical chemistry. B\| PubMed ID: 30001130	2018

Takuya Akita

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