Nanoscale Stereochemistry in Liquid Crystals

Tschierske, Carsten

doi:10.1002/9783527625345.ch9

Cited by 21 publications

(12 citation statements)

References 99 publications

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“…There is a large number of reports about fluid mirror symmetry broken smectic LC phases of bent-core molecules that are optically isotropic and form macroscopic chiral domains, therefore designated as dark-conglomerate (DC) phases (Figures 4(b,c) and 5(b,c)) [35,36,39,54,55]. Though also the HNF/HNC phases can form optically isotropic (dark) conglomerates we reserve the designation 'DC' here for the fluid DC phases.…”

Section: Dark Conglomerate (Dc) Type Isotropic Lamellar Phases Of Benmentioning

confidence: 99%

“…The helix can become long range at lower temperature when core packing becomes crystalline [211][212][213][214]. In the fluid LC state the coherence length of the helix is short and can be extended by introduction of permanent chirality into the molecules [216][217][218] or by chiral dopands which remove helix inversions and lead to uniform chirality (sergeant and soldier principle [25]) [54].…”

Section: Helical Order In Columnsmentioning

confidence: 99%

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Mirror symmetry breaking in liquids and liquid crystals

Tschierske

2018

Liquid Crystals

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101

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In the recent two decades liquid crystal science has contributed significantly to the understanding of mirror symmetry breaking and spontaneous emergence of chirality in fluids. This account tries to summarise the current state of understanding of mirror symmetry breaking in the liquid and liquid crystalline mesophases, ranging from isotropic liquids, via cubic, columnar and tetragonal SmQ phases of polycatenar compounds, the twist bend nematic phases of bent dimesogens to the heliconical and conglomerate type smectic phases of bent-core mesogens. Especially, the importance of dynamic chirality synchronisation of molecular conformers, cooperativity, helical superstructures, layer chirality, network formation, as well as chiral and achiral surface effects is discussed. At the end the transition from local to absolute symmetry breaking, chirality amplification and the relevance for the emergence of uniform chirality in prebiotic fluids and biosystems are considered. Dynamic Mirror Symmetry Breaking Transiently chiral molecules Cooperativity Super structural chirality Chirality synchronisation in fluids Network connectivity

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Section: Dark Conglomerate (Dc) Type Isotropic Lamellar Phases Of Benmentioning

confidence: 99%

Section: Helical Order In Columnsmentioning

confidence: 99%

Mirror symmetry breaking in liquids and liquid crystals

Tschierske

2018

Liquid Crystals

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101

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“…[20a, b] The physicochemical properties of disc-like molecules of medium size thus warrants further investigation, and herein we report a synthetic study of 1,3,5-triaroylbenzene in pressurized hot water. [21] Results and Discussion Formation of 1,3,5-tribenzyolbenzenes: All reactions gave colorless powders in various amounts depending on the reaction conditions. The solid products were shown to be 1,3,5-tribenzyolbenzene on the following grounds: 1) Its melting point (118-119 8C) was in good agreement with the reported melting point (119 8C).…”

Section: Introductionmentioning

confidence: 99%

One‐Pot Synthesis of 1,3,5‐Tribenzoylbenzenes by Three Consecutive Michael Addition Reactions of 1‐Phenyl‐2‐propyn‐1‐ones in Pressurized Hot Water in the Absence of Added Catalysts

Tanaka

Nakamura

Iwado

et al. 2010

Chemistry A European J

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Cyclotrimerization of 1-phenyl-2-propyn-1-one in pressurized hot water gave 1,3,5-tribenzoylbenzene in one pot in 65 % yield after 7 min at 200 °C, or in 74 % yield after 60 min at 150 °C. The reaction did not take place in the absence of water, and added base promoted the reaction at 250 °C, suggesting a mechanism of three-consecutive Michael addition reactions. The reaction rates increased with temperature, but the yield of 1,3,5-tribenzoylbenzene decreased at the expense of formation of acetophenone as a side product at higher temperatures. p-Methyl and p-chloro-substituents on the phenyl ring retarded and enhanced the reaction, respectively. A mechanism involving the enol of benzoylacetaldehyde at a branching point of the pathway leading to 1,3,5-tribenzoylbenzene and acetophenone was suggested.

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“…Mirror symmetry breaking is a basic feature of living matter which was in the recent two decades also observed in some cases of LC phases. [2][3][4][5][6][7][8][9][10][11][12][13][14][15] Dark conglomerate phases (DC [*] phases) represent one class of such spontaneously mirror symmetry broken mesophases exhibited by BCLCs. 3,[16][17][18][19] They are optically isotropic and therefore characterized by completely dark appearance between crossed polarizers, whereas under slightly uncrossed polarizers chiral domains of opposite handedness can be observed.…”

Section: Introductionmentioning

confidence: 99%

“…[2][3][4][5][6][7][8][9][10][11][12][13][14][15] Dark conglomerate phases (DC [*] phases) represent one class of such spontaneously mirror symmetry broken mesophases exhibited by BCLCs. 3,[16][17][18][19] They are optically isotropic and therefore characterized by completely dark appearance between crossed polarizers, whereas under slightly uncrossed polarizers chiral domains of opposite handedness can be observed. Related chiral domains were recently also observed in some nematic phases of dimesogens with odd-numbered spacers (twist bend nematic phases (N TB )), [9][10][11]20 in SmC phases formed by some azobenzene-based BCLCs, 21 in bicontinuous cubic phases 22 and even in isotropic liquids formed by some polycatenar molecules.…”

Section: Introductionmentioning

confidence: 99%