Long-alkyl-chain-derivatized imidazolium salts and ionic liquid crystals with tailor-made properties

Wang, Xinjiao; Sternberg, Michelle; Köhler, Florian; Melcher, Berthold U.; Wasserscheid, Peter; Meyer, Karsten

doi:10.1039/c3ra47250g

Cited by 47 publications

(56 citation statements)

References 48 publications

(35 reference statements)

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“…The observation of SmA mesophases for imidazolium salts 1-n (n = 11, 15) and 2 was not unexpected, since structurally related 1,3-bis(n-alkyl)imidazolium salts with long alkyl chains are known to adopt thermotropic SmA phases [54][55][56][57][58][59]. However, inspection of the literature data, some of which are collected in Table 3, shows that the clearing points of the 4,5-disubstituted ILCs are lower than those of 1,3-analogues.…”

Section: Discussionmentioning

confidence: 99%

“…Even the homologue with n-dodecyl groups in the 1-and 3-positions, 5-12, exhibits a similar clearing point as 1-15 and 2 despite its lower amphiphilic character. Since 5-12 also has a lower melting point, its mesophase temperature range is about 49 ] − is about 1.5 times as large [65]) [54,57]. Compound 1-11 also has a higher melting point and lower clearing point than 5-12 [56].…”

Section: Discussionmentioning

confidence: 99%

“…From the library of compounds, we selected six 4,5-bis(n-alkyl)azolium salts (1-n (n = 7, 11, 15) and 2-4, Scheme 1) and investigated their thermal characteristics. The data were compared with those reported for analogous 1,3-bis(n-alkyl)imidazolium and 2-[3,4-bis(n-alkyloxy)phenyl]-1,3-dimethylimidazolium ILCs (for example, 5-n and 6-n in Scheme 1) [38,[54][55][56][57][58][59]. Collectively, the results that will be described below show how the disposition of long alkyl chains around five-membered, heteroaromatic, cationic cores affects the thermal characteristics of the resulting salts.…”

Section: Introductionmentioning

confidence: 99%

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Substituted Azolium Disposition: Examining the Effects of Alkyl Placement on Thermal Properties

et al. 2019

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We describe the thermal phase characteristics of a series of 4,5-bis(n-alkyl)azolium salts that were studied using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), polarized-light optical microscopy (POM), and synchrotron-based small- to wide-angle X-ray scattering (SWAXS) measurements. Key results were obtained for 1,3-dimethyl-4,5-bis(n-undecyl)imidazolium iodide (1-11), 1,3-dimethyl-4,5-bis(n-pentadecyl)- imidazolium iodide (1-15), and 1,2,3-trimethyl-4,5-bis(n-pentadecyl)imidazolium iodide (2), which were found to adopt enantiotropic smectic A mesophases. Liquid-crystalline mesophases were not observed for 1,3-dimethyl-4,5-bis(n-heptyl)imidazolium iodide (1-7), 3-methyl-4,5-bis(n-penta-decyl)thiazolium iodide (3), and 2-amino-4,5-bis(n-pentadecyl)imidazolium chloride (4). Installing substituents in the 4- and 5-positions of the imidazolium salts appears to increase melting points while lowering clearing points when compared to data reported for 1,3-disubstituted analogues.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Substituted Azolium Disposition: Examining the Effects of Alkyl Placement on Thermal Properties

et al. 2019

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“…At least 500,000 time steps have been used for equilibration, followed by 500,000 time steps of production runs; longer equilibration were run close to the transition points. [36,37]) and 1:2 stoichiometry (right, Reference [5,[38][39][40]). (Bottom) schematic representation of the ion pairs of Gay-Berne (GB) and Lennard-Jones (LJ) particles used in the simulations.…”

Section: Methodsmentioning

confidence: 99%

Comparison of the Mesomorphic Behaviour of 1:1 and 1:2 Mixtures of Charged Gay-Berne GB(4.4,20.0,1,1) and Lennard-Jones Particles

2018

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We present a Molecular Dynamics study of mixtures of charged Gay-Berne (GB) ellipsoids and spherical Lennard-Jones (LJ) particles as models of ionic liquids and ionic liquid crystals. The GB system is highly anisotropic (GB(4.4,20.0,1,1)) and we observe a rich mesomorphism, with ionic nematic and smectic phases in addition to the isotropic mixed phase and crystalline phases with honeycomb structure. The systems have been investigated by analyzing the orientational and translational order parameters, as well as radial distribution functions. We have directly compared 1:1 mixtures, where the GB and LJ particles have a charge equal in magnitude and opposite in sign, and 1:2 mixtures where the number of LJ particles is twice as large compared to the GB and their charge half in magnitude. The results highlight the role of the long-range isotropic electrostatic interaction compared to the short-range van der Waals anisotropic contribution, and the effect of the stoichiometry on the stability of ionic mesophases.

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“…Mesogens with two C10 or longer alkyl chains 41 (and their mixtures) show SmA phases with temperature windows strongly dependent on their counter ion. Recent work showed that room temperature mesophases are in reach for these straightforward mesogens equipped with BF 4 − or ClO 4 − anions [ 112 ]. Recent work also demonstrates the advantages of using such compounds ( 41 , n = 12, X − = I 3 − ) as anisotropic electrolytes in dye-sensitized solar cells [ 113 ].…”

Section: Materials Development In Ionic Liquid Crystalsmentioning

confidence: 99%

Key Developments in Ionic Liquid Crystals

Fernandez

Kouwer²

2016

IJMS

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Ionic liquid crystals are materials that combine the classes of liquid crystals and ionic liquids. The first one is based on the multi-billion-dollar flat panel display industry, whilst the latter quickly developed in the past decades into a family of highly-tunable non-volatile solvents. The combination yields materials with a unique set of properties, but also with many challenges ahead. In this review, we provide an overview of the key concepts in ionic liquid crystals, particularly from a molecular perspective. What are the important molecular parameters that determine the phase behavior? How should they be introduced into the molecules? Finally, which other tools does one have to realize specific properties in the material?

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Long-alkyl-chain-derivatized imidazolium salts and ionic liquid crystals with tailor-made properties

Abstract: New ionic liquids and ionic liquid crystalline materials with custom-tailored properties were synthesized based on long-alkyl-chain-derivatized 1,3-dialkylimidazolium salts.

Cited by 47 publications

References 48 publications

Substituted Azolium Disposition: Examining the Effects of Alkyl Placement on Thermal Properties

Substituted Azolium Disposition: Examining the Effects of Alkyl Placement on Thermal Properties

Comparison of the Mesomorphic Behaviour of 1:1 and 1:2 Mixtures of Charged Gay-Berne GB(4.4,20.0,1,1) and Lennard-Jones Particles

Key Developments in Ionic Liquid Crystals

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