Mechanism of the Transformation of a Stiff Polymer Lyotropic Nematic Liquid Crystal to the Cholesteric State by Dopant-Mediated Chiral Information Transfer

Green, Mark M.; Zanella, Stefania; Gu, Hongwei; Sato, Takahiro; Gottarelli, Giovanni; Jha, Salil K.; Spada, Gian Piero; Schoevaars, Anne Marie; Feringa, Ben L.; Teŕamoto, Akio

doi:10.1021/ja981393t

Cited by 95 publications

(69 citation statements)

References 40 publications

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“…The periodic oblique stripes observed in each rightor left-handed helical block (blue and red colors in Figure 5 (right), respectively), which originated from a one-handed helical array of the side groups, were tilted clockwise or anticlockwise at +42 and -411, respectively, with respect to the main-chain axis. 15 Chain-to-chain spacing (B1.9 nm) and helical pitch (B2.2 nm) are similar for the copolymers and homopolymer (Table 2).…”

Section: Amplification Of Macromolecular Helicity In Poly(phenylacetymentioning

confidence: 83%

“…If the solution contains enantiomeric or diastereomeric right-and left-handed helices, q c also depends on the excess of the one helical sense. 15,16,18 Under the constant copolymer concentration of 15 wt% in benzene at B25 1C, the q c value of poly(1L m -co-1D n ) was found to increase with the increasing percentage ee of the copolymer components, where a larger q c value means an increased preference of the one-handedness, and the copolymers with 30-50% ee of the components showed as large a q c value as that of the homopolymer poly-1L (100% ee; Figure 2C). This remarkable increase in the q c value against the percentage ee of the copolymers (positive nonlinear effect) indicated a significant amplification of the helical-sense excess in the LC state, whereas in the dilute benzene solution, chiral information of the pendants that covalently bonded to the copolymer backbone was hardly transformed into a polymer backbone ( Figure 2C, inset).…”

Section: Amplification Of Macromolecular Helicity In Poly(phenylacetymentioning

confidence: 99%

“…Green et al 15 further extended the principle to the liquid crystalline (LC) systems, and found that the helical-sense bias of optically active polyisocyanates was further amplified in the polymer backbones as a greater excess of a single-handed helix through self-assembly into a lyotropic cholesteric liquid crystal; this effect was considered to be due to the reduction in population of the energetically unfavorable, kinked helical reversals in the LC state. A similar, but non-covalent, hierarchical amplification of helical chirality was observed for a dynamic helical, charged poly(phenylacetylene) in water.…”

Section: Introductionmentioning

confidence: 99%

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Amplification of macromolecular helicity of dynamic helical poly(phenylacetylene)s bearing non-racemic alanine pendants in dilute solution, liquid crystal and two-dimensional crystal

Ohsawa

Sakurai

Nagai

et al. 2011

Polym J

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Optically active poly(phenylacetylene) copolymers composed of non-racemic phenylacetylenes bearing L-and D-alanine decyl esters as the side groups (poly(1L m -co-1D n ), m4n) were prepared by the copolymerization of the corresponding L-and D-phenylacetylenes with different enantiomeric excesses using a rhodium catalyst; their chiral amplification of the helical conformation as an excess of one-handedness in a dilute solution, in a lyotropic liquid-crystalline (LC) state and in a twodimensional (2D) crystal on substrate was investigated by measuring the circular dichroism spectra of the copolymers at different temperatures, mesoscopic cholesteric twist in the LC state (cholesteric helical pitch) and high-resolution atomic force microscopy images of the self-assembled 2D helix-bundle structures of the copolymer chains, respectively.

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Section: Amplification Of Macromolecular Helicity In Poly(phenylacetymentioning

confidence: 83%

Section: Amplification Of Macromolecular Helicity In Poly(phenylacetymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Amplification of macromolecular helicity of dynamic helical poly(phenylacetylene)s bearing non-racemic alanine pendants in dilute solution, liquid crystal and two-dimensional crystal

Ohsawa

Sakurai

Nagai

et al. 2011

Polym J

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“…The obvious application of low molecular weight compounds that form nematic phases is to use them in small amounts as dopants to induce chirality in nematic host materials. 18 There is great interest in 'sergeant-soldier' effects whereby a chiral dopant, not even necessarily optically pure, propagates chirality to achiral bulk surroundings, for example, an achiral commercial nematic phase.…”

Section: Scheme 15mentioning

confidence: 99%

Mesogenic sugars. From aldoses to liquid crystals and surfactants

et al. 2000

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Amphiphilic sugar derivatives, formed by condensation of functionalized aliphatic chains with aldoses, form liquid crystals, in most cases smectic. A puzzling observation was the failure of the S,S-acetals of 6-deoxy sugars, L-rhamnose and D-fucose, to form such phases. A satisfactory model to explain this behavior involves-in most cases-the formation of columns, which are destabilized with the deoxy sugars in which the apolar end methyl groups are pushed together.Despite the abundance of chiral centers in the mono-and disaccharides used the smectic phases themselves in general display no chirality. By appropriate molecular design in which the amphiphilic character was deliberately suppressed it was possible to prepare glucose derivatives that exhibit chiral nematic phases as well as impressive helical twisting powers. Simple condensation chemistry is used to produce such derivatives.The amphiphilic character can be deliberately enhanced, and this is readily achieved in double headed 'gemini' derivatives formed by condensation of glucose or lactose with a long chain diamine followed by reduction followed by acylation of the nitrogen atoms with long chain acyl anhydrides. The thermodynamics of micellization of precursors to these derivatives have been studied. The gemini derivatives themselves display remarkable properties including the formation of giant vesicles and an appreciable capacity for the solubilization of hydrocarbons.

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“…The prominent functions of these biological components have motivated chemists to design artificial helical architectures (1)(2)(3)(4)(5)(6)(7)(8), which can be used for a variety of applications such as chiral separation (9,10) and sensing (11)(12)(13)(14)(15), asymmetric synthesis (16), liquid crystals (17)(18)(19), nonlinear optics (20,21), and so forth. Recently, a hot issue of chirality has emerged in relation to the helicity of the hexagonal carbon lattice in carbon nanotubes, because it determines the conductive properties of carbon nanotubes (22)(23)(24).…”

mentioning

confidence: 99%

Self-assembled graphitic nanotubes with one-handed helical arrays of a chiral amphiphilic molecular graphene

Jin

Fukushima²,

Niki³

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

262

177

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Self-assembly of a Gemini-shaped, chiral amphiphilic hexa-perihexabenzocoronene having two chiral oxyalkylene side chains, along with two lipophilic side chains, yields graphitic nanotubes with one-handed helical chirality. The nanotubes are characterized by an extremely high aspect ratio of >1,000 and have a uniform diameter of 20 nm and a wall thickness of 3 nm. The nanotubes with right-and left-handed helical senses were obtained from the (S)-and (R)-enantiomers of the amphiphile, respectively, due to an efficient translation of point chirality into supramolecular helical chirality. The (S)-and (R)-enantiomers coassemble at varying mole ratios to give nanotubes, whose circular dichroism profiles are almost unchanged over a wide range of the enantiomeric excess of the amphiphile (100 -20%). The high level of chirality amplification thus observed indicates a long-range cooperativity in the selfassembling process. In sharp contrast, a hexabenzocoronene amphiphile with chiral lipophilic side chains did not form nanotubular assemblies. The present work demonstrates the majority rule in noncovalent systems and also may provide a synthetic strategy toward realization of molecular solenoids. chirality ͉ self-assembly H elicity is one of the most essential structural elements for certain biomolecules such as peptides and DNA. The prominent functions of these biological components have motivated chemists to design artificial helical architectures (1-8), which can be used for a variety of applications such as chiral separation (9, 10) and sensing (11-15), asymmetric synthesis (16), liquid crystals (17-19), nonlinear optics (20, 21), and so forth. Recently, a hot issue of chirality has emerged in relation to the helicity of the hexagonal carbon lattice in carbon nanotubes, because it determines the conductive properties of carbon nanotubes (22-24). Conductive polymers with helical architectures (25) also have attracted attention in view of the concept of molecular solenoids (26,27), although this concept has yet been a dream of scientists, because there are no molecular objects that fulfill certain requisites for conductivity and helicity. Here, we report an example of conductive tubular objects consisting of one-handed helical arrays of a -stacked chiral molecular graphene. Self-assembly of hexa-peri-hexabenzocoronene (HBC) derivatives to form discotic liquid crystals and nanofibers has been studied extensively by Müllen and coworkers (28,29). We recently found that an amphiphilic HBC derivative (1) (Fig. 1) self-assembles in polar organic solvents such as tetrahydrofuran (THF) to give graphitic nanotubes, whose wall consists of a bilayer tape formed from bilaterally coupled columns of -stacked HBC units (30). In the course of this work, we have noticed that the self-assembly of 1, although achiral, gives a mixture of coiled and tubular assemblies under certain conditions, suggesting that the tubular objects also bear a helical structural element. This observation prompted us to design chiral HBC amphiphiles 2 and 3 (Fi...

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Mechanism of the Transformation of a Stiff Polymer Lyotropic Nematic Liquid Crystal to the Cholesteric State by Dopant-Mediated Chiral Information Transfer

Abstract: Mechanism of the transformation of a stiff polymer lyotropic nematic liquid crystal to the cholesteric state by dopant-mediated chiral information transfer Green, M.M.

Cited by 95 publications

References 40 publications

Amplification of macromolecular helicity of dynamic helical poly(phenylacetylene)s bearing non-racemic alanine pendants in dilute solution, liquid crystal and two-dimensional crystal

Amplification of macromolecular helicity of dynamic helical poly(phenylacetylene)s bearing non-racemic alanine pendants in dilute solution, liquid crystal and two-dimensional crystal

Mesogenic sugars. From aldoses to liquid crystals and surfactants

Self-assembled graphitic nanotubes with one-handed helical arrays of a chiral amphiphilic molecular graphene

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