Dyes witth Negative Dichorism for Liquid Crystal Displays Based on the Guest-Host Effect

Rumyantsev, V. G.; Иващенко, А. В.; Muratov, V. M.; Lazareva, V. T.; Prudnikova, Elena K.; Blinov, L. M.

doi:10.1080/00268948308084257

Cited by 25 publications

(9 citation statements)

References 5 publications

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“…It is necessary to note that the azodye (12) is the first representative of a bis-azodye of the T-type. Sufficiently high value of negative dichroism testifies that obtained T-dyes (5, [9][10][11][12] have the structure proposed on the scheme but not alternative structures (15-19). The structures (15-19) have a lower geometric anisotropy (ratio of the length of T-dye molecule to its width) in comparison with the structures (5, [9][10][11][12]; in the case of realization of structures (15-19) lower values of negative dichroism would be expected.…”

Section: -Arylazoimidazo[2 I-b]-1 3 4-thiadiazoles-new Dichroic Tmentioning

confidence: 99%

“…Printed in the United States of America 5-Arylazoimidazo[2, I-b]-I ,3,4-Thiadiazoles-New Dichroic T-Dyes For LCD A. V. IVASHCHENKO, 0. S. PETROVA and V. V. TITOV Institute of the Ministry of Chemical industry, Moscow, USSR (Received July 14, 1986)INTRODUCTIONContinuing research of dichroic T-dye~l-~ we have obtained new 5-arylazo-2,6-diarylimidazo[2,I-b]-l,3,4-thiadiazoles(5,(9)(10)(11)(12). The compounds (2-5) have been synthesized by known methods.5*6…”

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confidence: 99%

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5-Arylazoimidazo[2, I-b]-1, 3, 4-Thiadiazoles—New Dichroic T-Dyes For LCD

Иващенко¹,

Petrova²,

Титов³

1987

Molecular Crystals and Liquid Crystals

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Section: -Arylazoimidazo[2 I-b]-1 3 4-thiadiazoles-new Dichroic Tmentioning

confidence: 99%

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confidence: 99%

5-Arylazoimidazo[2, I-b]-1, 3, 4-Thiadiazoles—New Dichroic T-Dyes For LCD

Иващенко¹,

Petrova²,

Титов³

1987

Molecular Crystals and Liquid Crystals

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“…Amongst the most important energetic azo compounds, there are derivatives of 1,2,3,4-tetrazine ( Figure 1, 1a), tetrazole (1b), 1,2,4-triazole (1c), and pyrazole (1d) [8][9][10][11]. Nitrated imidazoles are of great interest due to their low sensitivity towards various stimuli and high detonation parameters, but Nevertheless, several derivatives with aliphatic or aromatic substituents have been reported and they may serve as photoswitches and dyes [16][17][18][19][20][21]. 2,2′-Azobis(1H-imidazole-4,5-dicarbonitrile) (TCAD), its alkyl derivatives, salts, metal complexes, hydrolysis products, hydrazine, and hydroxylamine adducts were recognized as dyes as well [22].…”

Section: Introductionmentioning

confidence: 99%

Structure and Thermal Properties of 2,2′-Azobis(1H-Imidazole-4,5-Dicarbonitrile)—A Promising Starting Material for a Novel Group of Energetic Compounds

et al. 2020

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A high-nitrogen compound, 2,2′-azobis(1H-imidazole-4,5-dicarbonitrile) (TCAD), was synthesized from commercially available 2-amino-1H-imidazole-4,5-dicarbonitrile. It was characterized with infrared and nuclear magnetic resonance spectroscopy. Its structure was determined by single crystal X-ray diffraction. The crystal of TCAD tetrahydrate is monoclinic, with space group P21/c with crystal parameters of a = 10.2935(2) Å, b = 7.36760(10) Å, c = 20.1447(4) Å, V = 1500.27(5) Å3, Z = 4, and F(000) = 688. Computational methods were used in order to fully optimize the molecular structure, calculate the electrostatic potential of an isolated molecule, and to compute thermodynamic parameters. TCAD has very high thermal stability with temperature of decomposition at 369 °C. Kinetics of thermal decomposition of this compound were studied and apparent energy of activation as well as the maximum safe temperature of technological process were determined.

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“…In these devices, contrast ratios are not necessarily as dependent on the order parameters of the dyes as they are in conventional guest-host devices [18]. Although negative dichroic dyes have been the subject of much less research than positive dichroic dyes, there have been a range of reports of dyes exhibiting negative dichroism, including azo compounds [14,19], anthraquinones [20][21][22][23][24][25] and tetrazines [26]. More recently than much of the initial research into negative dichroic dyes, a device mode has been suggested with wide viewing angles and a high contrast ratio using a black mixture of negative dichroic dyes, operating in both reflective and transmissive modes and without a polariser [27].…”

Section: Introductionmentioning

confidence: 99%

“…These compounds have also been proposed for use in devices based on guest-host mixtures [13], in which the maximum absorbance occurs when the electric vector of incident polarised light is orientated perpendicular to the director. Such dyes readily enable devices that exhibit positive contrast [14], and suitable mixtures of negative dichroic dyes also enable switching between black and transmitting states [15].…”

Section: Introductionmentioning

confidence: 99%

Guest–host systems containing anthraquinone dyes with multiple visible transitions giving positive and negative dichroic order parameters: an assessment of principal molecular axes and computational methods

et al. 2017

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(2017) Guest-host systems containing anthraquinone dyes with multiple visible transitions giving positive and negative dichroic order parameters: an assessment of principal molecular axes and computational methods. Liquid Crystals, Northumbria University has developed Northumbria Research Link (NRL) to enable users to access the University's research output. Copyright © and moral rights for items on NRL are retained by the individual author(s) and/or other copyright owners. Single copies of full items can be reproduced, displayed or performed, and given to third parties in any format or medium for personal research or study, educational, or not-for-profit purposes without prior permission or charge, provided the authors, title and full bibliographic details are given, as well as a hyperlink and/or URL to the original metadata page. The content must not be changed in any way. Full items must not be sold commercially in any format or medium without formal permission of the copyright holder. The full policy is available online: http://nrl.northumbria.ac.uk/policies.html This document may differ from the final, published version of the research and has been made available online in accordance with publisher policies. To read and/or cite from the published version of the research, please visit the publisher's website (a subscription may be required.)Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=tlct20 Three 1,4-disubstituted anthraquinone dyes with bis(4-n-butylphenyl) substituents connected via amine or amide linking groups have been studied as guest molecules dissolved in the nematic host E7. UV-visible absorption spectroscopy has shown each of the dyes to exhibit multiple absorption bands in the visible region, and dichroic order parameters obtained from polarised spectra of aligned guest-host samples were shown to differ significantly between the bands for each dye, and between the dyes. Time-dependent density functional theory calculations indicated that each dye exhibits several transitions, giving transition dipole moment vectors with a range of orientations, and fully atomistic molecular dynamics simulations of the guest-host mixtures showed differences in the calculated molecular alignments of the dyes. Combining the results from these two sets of calculations enabled a comparison of molecular alignment models based on the moments of inertia and the surface tensors of the dyes. The match between calculated and experimental values was improved significantly when using the surface tensor rather than the moment of inertia model, indicating that the shapes of the molecular surfaces of these dyes are crucial to their alignment. A novel method of calculating polarised UV-visible absorption spectra of dyes in liquid crystal hosts is also presented.

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Dyes witth Negative Dichorism for Liquid Crystal Displays Based on the Guest-Host Effect

Cited by 25 publications

References 5 publications

5-Arylazoimidazo[2, I-b]-1, 3, 4-Thiadiazoles—New Dichroic T-Dyes For LCD

5-Arylazoimidazo[2, I-b]-1, 3, 4-Thiadiazoles—New Dichroic T-Dyes For LCD

Structure and Thermal Properties of 2,2′-Azobis(1H-Imidazole-4,5-Dicarbonitrile)—A Promising Starting Material for a Novel Group of Energetic Compounds

Guest–host systems containing anthraquinone dyes with multiple visible transitions giving positive and negative dichroic order parameters: an assessment of principal molecular axes and computational methods

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