Study of the mesomorphic behaviour through the structure modification of azo and acetylene pyridinium and imidazolium-based ionic liquid crystals

Filippi, Natan Glauber; Mezalira, Daniela Zambelli; Ovalle, Saul; Westphal, Eduard

doi:10.1080/02678292.2016.1199817

Cited by 19 publications

(7 citation statements)

References 51 publications

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“…Westphal and our groups independently disclosed azobenzenes tethered to imidazolium, pyridinium, guanidinium and amidinium head groups (Scheme 24). [63,64,191] Westphal nicely demonstrated that SmC phases appear as soon as the charged moiety is moved away from the rigid core, regardless whether it is an azobenzene or tolane unit (Scheme 24, 53 and 54 ) [191] . We discovered the first ILC de Vries materials by examining the XRD data of azobenzene ILCs with different spacer lengths and head groups (Scheme 24, 55(+) ) [63,64] .…”

Section: Rare Ilc Phasesmentioning

confidence: 98%

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Current Topics in Ionic Liquid Crystals

et al. 2021

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Ionic liquid crystals (ILCs), that is, ionic liquids exhibiting mesomorphism, liquid crystalline phases, and anisotropic properties, have received intense attention in the past years. Among others, this is due to their special properties arising from the combination of properties stemming from ionic liquids and from liquid crystalline arrangements. Besides interesting fundamental aspects, ILCs have been claimed to have tremendous application potential that again arises from the combination of properties and architectures that are not accessible otherwise, or at least not accessible easily by other strategies. The current review highlights recent developments in ILC research, starting with some key fundamental aspects. Further subjects covered include the synthesis and variations of modern ILCs, including the specific tuning of their mesomorphic behavior. The review concludes with reflections on some applications that may be within reach for ILCs and finally highlights a few key challenges that must be overcome prior and during true commercialization of ILCs.

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Section: Rare Ilc Phasesmentioning

confidence: 98%

“… Azobenzene salts 53 and 54 studied by Westphal [191] and azobenzene salts 55(+) studied by Giesselmann and Laschat, [63,64] with the latter exhibiting de Vries‐like behavior.…”

Section: Rare Ilc Phasesmentioning

confidence: 99%

Current Topics in Ionic Liquid Crystals

et al. 2021

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“…Heterocycles are of crucial importance in the design and synthesis of novel organic functional materials, especially in the development of thermotropic liquid crystals, since phase structure, polarity, geometry, luminescence and many other molecular properties can be varied by the introduction of heteroatoms [42][43][44][45][46][47][48]. Generally, the pyridiniumbased ILC have been known since long time, thermotropic mesomorphism of pyridinium salts was noticed as early as 1938 by Knight and Shaw [8].…”

Section: Introductionmentioning

confidence: 99%

Star-shaped supramolecular ionic liquid crystals based on pyridinium salts

et al. 2018

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Series of novel star-shaped liquid crystals containing [1,1ʹ-biphenyl]-4,4ʹ-diyl diisonicotinate mesogens with various counterions (Br − , B-SO 3 − ,C-SO 3 − ,H 2 PO 4 − , BF 4 − ) have been synthesized and characterized, which display a nematic phase. The molecular structures of the liquid crystals, thereof consisting of rod-like mesogens linked together by different long alkyl spacers to a small disc-like core of central benzene-1,3,5-triyl triisonicotinate, have been fully characterized by 1 H NMR. Their thermal and supramolecular organization behaviours have been studied by combining polarized optical microscopy, differential scanning calorimetry and small-angle X-ray scattering. These investigations showed that the mesophase temperature range increased with increasing alkyl chain length and the clearing point decreased with increase of anion size. These star-shaped liquid crystals have a long and ordered molecular structure, the electron delocalization of the π-π stacking conjugation effect and the electrostatic attraction of ionic make them have good ferroelectric properties and ionic conductivity properties. The interest in preparing ionic liquid crystal with a nematic phase lies in the technological applications as it is well known that the nematic phase has the highest fluidity of all liquid crystalline phases and hence the possibility to align it by applying an external electric/magnetic field, commonly used in electro-optical devices.

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“…Their thermal properties are influenced by the alkyl chain length, the nature of linking groups, while the dominant factor for 24 was the size of perfluorinated ring [29].…”

Section: N-alkylated Pyridinium Salts Derived From Picolinementioning

confidence: 99%

“…Several other pyridinium ILCs having a second aromatic ring connected to the 4-position of the pyridinium ring via a linking group (azo, 22, acetylene, 23, or imine, 24) were designed and investigated [28,29]. Their thermal properties are influenced by the alkyl chain length, the nature of linking groups, while the dominant factor for 24 was the size of perfluorinated ring [29].…”

Section: N-alkylated Pyridinium Salts Derived From Picolinementioning

confidence: 99%

Ionic Liquid Crystals Based on Pyridinium Salts

Cı̂rcu¹

2017

Progress and Developments in Ionic Liquids

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Study of the mesomorphic behaviour through the structure modification of azo and acetylene pyridinium and imidazolium-based ionic liquid crystals

Cited by 19 publications

References 51 publications

Current Topics in Ionic Liquid Crystals

Current Topics in Ionic Liquid Crystals

Star-shaped supramolecular ionic liquid crystals based on pyridinium salts

Ionic Liquid Crystals Based on Pyridinium Salts

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