Helical Polyacetylene: Asymmetric Polymerization in a Chiral Liquid-Crystal Field

Akagi, Kazuo

doi:10.1021/cr900198k

Cited by 378 publications

(266 citation statements)

References 213 publications

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“…Since 1998, Akagi et al have developed the chiral nematic liquid crystal field with the induced polymerization of various polymerizable monomers involving acetylene gas with the help of catalytic and electrochemical polymerization reactions (Figures 29-31) [77,[148][149][150][151][152][153]. The helical shapes of polymers during polymerization are retained, because the resulting polymers are insoluble in these chiral liquid crystals.…”

Section: Catalytic and Electrochemical Polymerizationmentioning

confidence: 99%

“…Nevertheless, controlled mirror symmetry breaking (CMSB) might be one of the keys in the areas of organic and inorganic chemistry, supramolecular science, polymer science and materials science [77][78][79]. When most molecules and polymers have specific, handed stereogenic centers and/or handed stereogenic bonds, these substances become optically active or chiral.…”

Section: Introductionmentioning

confidence: 99%

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Supramolecular Chirality: Solvent Chirality Transfer in Molecular Chemistry and Polymer Chemistry

Fujiki

2014

Symmetry

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Controlled mirror symmetry breaking arising from chemical and physical origin is currently one of the hottest issues in the field of supramolecular chirality. The dynamic twisting abilities of solvent molecules are often ignored and unknown, although the targeted molecules and polymers in a fluid solution are surrounded by solvent molecules. We should pay more attention to the facts that mostly all of the chemical and physical properties of these molecules and polymers in the ground and photoexcited states are significantly influenced by the surrounding solvent molecules with much conformational freedom through non-covalent supramolecular interactions between these substances and solvent molecules. This review highlights a series of studies that include: (i) historical background, covering chiral NaClO 3 crystallization in the presence of D-sugars in the late 19th century; (ii) early solvent chirality effects for optically inactive chromophores/fluorophores in the 1960s-1980s; and (iii) the recent development of mirror symmetry breaking from the corresponding achiral or optically inactive molecules and polymers with the help of molecular chirality as the solvent use quantity.

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Section: Catalytic and Electrochemical Polymerizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Supramolecular Chirality: Solvent Chirality Transfer in Molecular Chemistry and Polymer Chemistry

Fujiki

2014

Symmetry

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“…The CNs possess several advantages such as low cost, low density, nontoxicity, renewable nature biodegradability, and in particular they can form stable lyotropic N * -LCs phase above a critical concentration [12][13][14]. It has been reported that the N * -LCs phase was used as a hard template to synthesize other new materials with chiral nematic 2 Journal of Materials structures [15,16]. In this thesis, we attempted to prepare novel nanocomposites of conductive polymer and CNs in the cellulose N * -LCs reaction field for in situ asymmetric polymerization.…”

Section: Introductionmentioning

confidence: 99%

“…The electrical conductivity of the composite films could be enhanced significantly via doping of acid and the carbon black. Akagi [15] reported the polymerization of acetylene in an asymmetric reaction field constructed with chiral nematic LCs and showed that polyacetylene films formed from helical chains and fibrils can be synthesized. However, as far as we know, the systematic research on the preparation of the nanocomposites of PANI and CNs in the lyotropic N * -LCs reaction field is rarely exploited.…”

Section: Introductionmentioning

confidence: 99%

Nanocomposites of Polyaniline and Cellulose Nanocrystals Prepared in Lyotropic Chiral Nematic Liquid Crystals

Zhang

Wang

et al. 2013

Journal of Materials

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Stable lyotropic chiral nematic liquid crystals (N * -LCs) of cellulose nanocrystals (CNs) were prepared via hydrolysis using sulfuric acid. The lyotropic N * -LCs were used as an asymmetric reaction field to synthesize polyaniline (PANI) onto CNs by in situ polymerization. As a primary step, we examined the mesophase transition of the N * -LCs of CNs suspension before and after in situ polymerization of aniline (ANI) by polarizing optical microscopy. The structure of nanocomposites of PANI/CNs was investigated at a microscopic level using Fourier transform infrared spectroscopy and X-ray diffraction. Influence of the CNs-to-ANI ratio on the morphology of the nanocomposites was also investigated at macroscopic level by scanning electron and transmission electron microscopies. It is found that the weight ratio of CNs to aniline in the suspension significantly influenced the size of the PANI particles and interaction between CNs and PANI. Moreover, electrical properties of the obtained PANI/CNs films were studied using standard four-probe technique. It is expected that the lyotropic N * -LCs of CNs might be available for an asymmetric reaction field to produce novel composites of conjugated materials.

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“…INTRODUCTION Dynamic helical polymers, such as polyisocyanates, 1 polysilanes, 2 and polyacetylenes, [3][4][5][6][7] readily invert the helical sense owing to relatively low energy barriers for the helix reversal. 8 Thus, they can transform their higher order structures, for example, from helix to coil and/or from right-to left-handed helices, offering their potential application to chiral sensors, molecular memory, and so on.…”

mentioning

confidence: 99%

Molecular weight dependence of helical conformation of amino acid‐based polyphenylacetylenes

Shiotsuki

Kumazawa

Onishi

et al. 2011

J. Polym. Sci. A Polym. Chem.

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A well‐defined living polymerization catalyst, [(nbd)Rh{C(Ph)=CPh2}(PPh3)]/PPh3, produced a series of amino acid based polyphenylacetylene derivatives having a wide range of molecular weights (Mn: 1500–128,800) with relatively narrow polydispersity. On the basis of the CD and UV–vis spectra of the obtained polymers measured in DMF, plotting the [θ] and Kuhn dissymmetry factor, g, against the molecular weight revealed that their predominantly one‐handed helical conformation strongly depended on their molecular weights.

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Helical Polyacetylene: Asymmetric Polymerization in a Chiral Liquid-Crystal Field

Cited by 378 publications

References 213 publications

Supramolecular Chirality: Solvent Chirality Transfer in Molecular Chemistry and Polymer Chemistry

Supramolecular Chirality: Solvent Chirality Transfer in Molecular Chemistry and Polymer Chemistry

Nanocomposites of Polyaniline and Cellulose Nanocrystals Prepared in Lyotropic Chiral Nematic Liquid Crystals

Molecular weight dependence of helical conformation of amino acid‐based polyphenylacetylenes

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