Preparation of Furan-Based Monomers and Asymmetric Electrochemical Polymerization in Cholesteric Liquid Crystals: Optical Activity and Selective Reflection

Kawabata, Kohsuke; Yoneyama, Hiroyuki; Goto, Hiromasa

doi:10.1080/15421400902987636

Cited by 5 publications

(1 citation statement)

References 21 publications

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“…Poly 1 to Poly 8 and Poly 9 were synthesized by a previous reported method ,− Accordingly, COC (chiral inducer), monomer, and TBAP (supporting salt) were dissolved in 6CB as a nematic liquid crystal (N-LC) matrix to prepare electrolytes for Poly 1 to Poly 8. Cholesteryl acetate (CA, chiral inducer), 2,7-di(2-furyl)fluorene (monomer), and TBAP were dissolved in 6CB to prepare electrolytes for Poly 9-1 to Poly 9-4.…”

Section: Methodsmentioning

confidence: 99%

Molecular Order Imprint Polymerization of Furan–Thiophene-Based Monomers with Electrochemical Polymerization in Chiral Liquid Crystals

Komaba,

Yoneyama,

Goto

2024

ACS Appl. Polym. Mater.

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A polymerization reaction in chiral liquid crystal produced electrooptically active polymers from achiral furan−thiophene-based monomers. The set of polymers prepared in this study had characteristics of liquid crystal molecular order and organic semiconductors. The optically active aromatic copolymers were synthesized via an electrochemical method in cholesteric liquid crystals (Ch-LCs). Electrical properties and chirality can be tuned to choose suitable monomer units. The polymers obtained were evaluated by polarizing optical microscopy (POM), circular dichroism, UV−vis spectroscopy, cyclic voltammetry, reflectance spectroscopy, scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. POM observations of the products showed a vortex-type fingerprint texture. Polymerization of the monomers containing only two active polymerization sites produced the resultant compounds with good transcription of the fingerprint texture and chirality from the Ch-LC electrolyte solution. The membrane-forming behavior can be improved by introducing furans at the edges of monomers. The absorption bands derived from polarons and bipolarons as charge carriers of conducting polymers can be tuned by an electrical redox process and hydrazine vaporization treatment. Electrical control for the optical activity of the furan−thiophene-based polymers was achieved.

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Section: Methodsmentioning

confidence: 99%

Molecular Order Imprint Polymerization of Furan–Thiophene-Based Monomers with Electrochemical Polymerization in Chiral Liquid Crystals

Komaba,

Yoneyama,

Goto

2024

ACS Appl. Polym. Mater.

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“Absolute” Asymmetric Polymerization within Crystalline Architectures: Relevance to the Origin of Homochirality

Weissbuch

Lahav

2012

Materials Science and Technology

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The emergence of the homochiral proteins and nucleic acids, composed from residues of L-amino acids and D-sugars respectively, from the achiral prebiotic world still provides an unsolved conundrum in the field of the origin of life. This mist results from the fundamental symmetry rules as defined, at the end of the nineteenth century, by the Curie principle [1], which states that, '' . . . a physical event cannot have a symmetry lower than that of the event that caused it.''There are two classes of asymmetric transformation, which are in keeping with this symmetry rule. In the first class, chiral reactants are converted, via chemical reactions, into chiral products; in the second class, ''mirror-symmetry'' can be broken spontaneously in either a single or a small number of chemical reactions. In a large number of related independent events, however, the system will preserve its initial nonchiral symmetry. Such class of stochastic asymmetric transformations might have been relevant to chiro-biogenesis, provided the scenario can be accepted that life started in a small number of locations, and that the handedness generated by chance has been amplified and propagated during a competition with heterochiral architectures, such that one of the homochiral architectures has tripped and the other has won the rivalry [2][3][4][5].In this chapter, the second class of stochastic asymmetric synthesis of polymers -referred to as ''absolute'' asymmetric synthesis -and which has been materialized in laboratory experiments, is described. Several successful systems of ''mirror-symmetry breaking'' have been shown to comprise the following steps: spontaneous self-assembly of molecules into crystalline-like supramolecular architectures that create a local homochiral molecular environment exerting asymmetric induction in the ensuing propagation of the polymerization reaction. Farina [6] coined the term ''through-space'' asymmetric transformations in order to distinguish them from the common ''through-bond'' reactions.Here, attention is confined especially to the asymmetric transformations of achiral monomers within crystalline or quasi-crystalline architectures. In particular, the early studies of asymmetric polymerizations performed within enantiomorphous

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Synthesis of chiral inducers having double stereogenic centers for electrochemical polymerization in cholesteric liquid crystal medium

et al. 2014

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An enantiomeric pair of chiral inducers with double chiral carbons was synthesized by a simple three-step reaction strategy. The process affords the chiral inducers with good yield, high enantiomeric excess, and good compatibility with nematic liquid crystal. Addition of a small amount of the chiral inducers thus synthesized in this study produced cholesteric architecture. Electrochemical polymerization in the asymmetric liquid crystal environment affords chiroptically active polymers as atropisomers. The electrochemical polymerization under magnetic field of 4 T affords polymer films with linear dichroism. The polymers exhibit a significant color change from dark-green in the oxidized state to light-green in the reduced state. The redox process of the polymer films in an electrolyte provides a reversible absorption, circular dichroism, and linear dichroism spectral changes.

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Preparation of Furan-Based Monomers and Asymmetric Electrochemical Polymerization in Cholesteric Liquid Crystals: Optical Activity and Selective Reflection

Cited by 5 publications

References 21 publications

Molecular Order Imprint Polymerization of Furan–Thiophene-Based Monomers with Electrochemical Polymerization in Chiral Liquid Crystals

Molecular Order Imprint Polymerization of Furan–Thiophene-Based Monomers with Electrochemical Polymerization in Chiral Liquid Crystals

“Absolute” Asymmetric Polymerization within Crystalline Architectures: Relevance to the Origin of Homochirality

Synthesis of chiral inducers having double stereogenic centers for electrochemical polymerization in cholesteric liquid crystal medium

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