Nematic phases in achiral unsymmetrical four-ring bent-core azo compounds possessing strongly polar cyano and nitro moieties as end substituents: Synthesis and characterization

Debnath, Somen; Mohiuddin, Golam; Turlapati, Srikanth; Begum, Nazma; Sarkar, Dipika Debnath; Rao, V. Pandu Ranga

doi:10.1016/j.dyepig.2013.05.029

Cited by 27 publications

(9 citation statements)

References 52 publications

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“…24 Salamon et al reported another thiadiazole based BCN with K 33 > K 11 and the non-BCN behavior was assigned to the four alkyl chains connected to intermediate core rings which act like so spacers between molecules and prevents close polar packing. 41 However in our case the bend angle is identical ($146 ) for all the compounds 29,30 and hence it cannot be the dominant parameter in governing the elastic constants. Also the molecules do not have any lateral alkyl chains which may prohibit formation of polar clusters.…”

Section: Dielectric Anisotropy and Elastic Constantsmentioning

confidence: 62%

“…The bent-core compounds 11-2M-F, 11-2M-Cl and 11-2M-NO 2 are synthesized following a very simple and straightforward methodology of the standard procedures described elsewhere. 29,30 The unsymmetrical four-ring molecules possess an alkoxy chain attached at only one end of the bent-core molecule, while the other arm ends with a highly polar uoro/chloro/nitro substituent. The end polar substituent in one of the arms contributes a large dipole moment.…”

Section: Methodsmentioning

confidence: 99%

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Impact of terminal polar substitution on elastic, electro-optic and dielectric properties of four-ring bent-core nematic liquid crystals

et al. 2018

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Section: Dielectric Anisotropy and Elastic Constantsmentioning

confidence: 62%

Section: Methodsmentioning

confidence: 99%

Impact of terminal polar substitution on elastic, electro-optic and dielectric properties of four-ring bent-core nematic liquid crystals

et al. 2018

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“…The existence of mesophases near room temperature is very important for potential applications; consequently, lateral moieties are incorporated into the molecular architecture to lower the melting temperature [ 26 ]. On the other hand, polar terminal substituents and linking moieties were both important factors for the designed compounds, in terms of the formation, kind, thermal stability, and range of the observed mesophase [ 5 , 12 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ].…”

Section: Introductionmentioning

confidence: 99%

Synthetic, Mesomorphic, and DFT Investigations of New Nematogenic Polar Naphthyl Benzoate Ester Derivatives

et al. 2021

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Four new non-symmetrical derivatives based on central naphthalene moiety, 4-((4–(alkoxy)phenyl) diazenyl)naphthalen–1–yl 4–substitutedbenzoate (In/x), were prepared, and their properties were investigated experimentally and theoretically. The synthesized materials bear two wing groups: an alkoxy chain of differing proportionate length (n = 6 and 16 carbons) and one terminal attached to a polar group, X. Their molecular structures were elucidated via elemental analyses and FT-IR and NMR spectroscopy. Differential scanning calorimetry (DSC) and polarized optical microscopy (POM) were carried out to evaluate their mesomorphic properties. The results of the experimental investigations revealed that all the synthesized analogues possess only an enantiotropic nematic (N) mesophase with a high thermal stability and broad range. Density functional theory (DFT) calculations were in accordance with the experimental investigations and revealed that all prepared materials are to be linear and planar. Moreover, the rigidity of the molecule increased when an extra fused ring was inserted into the center of the structural shape, so its thermal and geometrical parameters were affected. Energy gap predictions confirmed that the I16/c derivative is more reactive than other compounds.

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“…During the cooling scan, all homologues of both compounds are enantiotropic in nature and exhibit a schlieren and marbled texture typically for a nematic mesophase. As observed, the nematic phase range decreases with an increasing chain length in both compounds [ 33 ]. Comp 19a 19b 19c 19d 19e 19f 19g 19h 19i n 4 5 6 7 8 9 10 11 12 X CN CN CN CN CN CN CN CN CN Comp 20a 20b 20c 20d 20e 20f 20g 20h 20i n 4 5 6 7 8 ...

…”

Section: Structure–property Relationshipmentioning

confidence: 72%

Liquid Crystals Investigation Behavior on Azo-Based Compounds: A Review

Razali

Jamain

2021

Polymers

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Liquid crystal is an intermediate phase between the crystalline solid and an isotropic liquid, a very common substance in our daily lives. Two major classes of liquid crystal are lyotropic, where a liquid crystal is dissolved in a specific solvent under a particular concentration and thermotropic, which can be observed under temperature difference. This review aims to understand how a structure of a certain azo compound might influence the liquid crystal properties. A few factors influence the formation of different liquid crystals: the length of the alkyl terminal chain, inter/intra-molecular interaction, presence of spacer, spacer length, polarization effects, odd-even effects, and the presence of an electron-withdrawing group or an electron-donating group. As final observations, we show the compound’s different factors, the other liquid crystal is exhibited, and the structure–property relationship is explained. Liquid crystal technology is an ideal system to be applied to products to maximize their use, especially in the electronic and medical areas.

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Nematic phases in achiral unsymmetrical four-ring bent-core azo compounds possessing strongly polar cyano and nitro moieties as end substituents: Synthesis and characterization

Cited by 27 publications

References 52 publications

Impact of terminal polar substitution on elastic, electro-optic and dielectric properties of four-ring bent-core nematic liquid crystals

Impact of terminal polar substitution on elastic, electro-optic and dielectric properties of four-ring bent-core nematic liquid crystals

Synthetic, Mesomorphic, and DFT Investigations of New Nematogenic Polar Naphthyl Benzoate Ester Derivatives

Liquid Crystals Investigation Behavior on Azo-Based Compounds: A Review

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