A new class of double alkyl-substituted, liquid crystalline imidazolium ionic liquids—a unique combination of structural features, viscosity effects, and thermal properties

Wang, Xinjiao; Heinemann, Frank W.; Yang, Mei; Melcher, Berthold U.; Fekete, Melinda; Mudring, Anja‐Verena; Wasserscheid, Peter; Meyer, Karsten

doi:10.1039/b914939b

Cited by 77 publications

(105 citation statements)

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“…[93][94][95][96][97][98] and references therein). ILCs typically consist of highly anisotropically shaped ions such as imidazolium ions with long N-alkyl substituents (i.e., C n H 2 n + 1 alkyl substituents with n ≥ 12).…”

Section: Structure Formation In Il Crystalsmentioning

confidence: 96%

“…[ 52 ] The corresponding experiment is summarized in Figure 7 . As a test system we have chosen 1,3-didodecylimidazolium tetrafl uoroborate [C 12 4 ] has been shown to undergo a transition to a smectic phase at approximately 430 K. [ 94 ] The degree of molecular ordering is followed by temperature-dependent IRAS (see Figure 7 a). An assignment of most peaks is straightforward, based on a comparison with previous work on similar ILs [ 99 ] and we refer to the original publication for further discussion.…”

Section: Adv Mater 2011 23 2571-2587mentioning

confidence: 99%

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Surface Science and Model Catalysis with Ionic Liquid‐Modified Materials

et al. 2011

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Materials making use of thin ionic liquid (IL) films as support-modifying functional layer open up a variety of new possibilities in heterogeneous catalysis, which range from the tailoring of gas-surface interactions to the immobilization of molecularly defined reactive sites. The present report reviews recent progress towards an understanding of "supported ionic liquid phase (SILP)" and "solid catalysts with ionic liquid layer (SCILL)" materials at the microscopic level, using a surface science and model catalysis type of approach. Thin film IL systems can be prepared not only ex-situ, but also in-situ under ultrahigh vacuum (UHV) conditions using atomically well-defined surfaces as substrates, for example by physical vapor deposition (PVD). Due to their low vapor pressure, these systems can be studied in UHV using the full spectrum of surface science techniques. We discuss general strategies and considerations of this approach and exemplify the information available from complementary methods, specifically photoelectron spectroscopy and surface vibrational spectroscopy.

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Section: Structure Formation In Il Crystalsmentioning

confidence: 96%

Section: Adv Mater 2011 23 2571-2587mentioning

confidence: 99%

Surface Science and Model Catalysis with Ionic Liquid‐Modified Materials

et al. 2011

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“…As a test system we have chosen the novel IL 1,3-didodecylimidazolium tetrafluoroborate [C 12 C 12 IM][BF 4 ], which was shown to undergo a phase transition to a smectic phase at approximately 430 K. [17] The IL was spin-coated onto a clean Pt(111) single crystal, which serves as a reflective support for the IRAS experiment (details are given in the Experimental Section). For this test system, the wetting behavior and the phase transitions were also followed by optical microscopy, as shown in Figure 1 The molecular ordering and phase transitions are followed by time-resolved IRAS during cooling of similar samples.…”

Section: Marek Sobotamentioning

confidence: 99%

Ordering and Phase Transitions in Ionic Liquid‐Crystalline Films

et al. 2010

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Watching phase transitions: Ordering processes and phase transitions in thin films of the liquid‐crystalline ionic liquid 1,3‐didodecylimidazolium tetrafluoroborate [C12C12IM][BF4] on Pt(111) (see picture) are studied by means of temperature‐dependent IR reflection absorption spectroscopy. The method allows in situ monitoring of the structural properties of liquid‐crystalline supported ionic liquid phase (SILP) catalysts under reaction conditions.

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“…By attaching one or two relatively long alkyl chains to the heterocyclic cation, mesomorphism is induced. [2][3][4][5][6][7][8][9] These mesogens can be considered as flexible amphiphiles. The alkyl chains might additionally be decorated with mesogenic groups to influence the phase behaviour.…”

Section: Introductionmentioning

confidence: 99%

T‐Shaped Ionic Liquid Crystals Based on the Imidazolium Motif: Exploring Substitution of the C‐2 Imidazolium Carbon Atom

Goossens

Wellens

Hecke

et al. 2011

Chemistry A European J

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In this contribution the first examples of so-called rigid-core, T-shaped imidazolium ionic liquid crystals, in which the C-2 atom of the imidazolium ring is substituted with an aryl moiety decorated with one or two alkoxy chains, are described. The length of the alkoxy chain(s) was varied from six to eighteen carbon atoms (n=6, 10, 14-18). Whereas the compounds with one long alkoxy chain display only smectic A phases, the salts containing two alkoxy chains exhibit smectic A, multicontinuous cubic, as well as hexagonal columnar phases, as evidenced by polarising optical microscopy, differential scanning calorimetry, and powder X-ray diffraction. Structural models are proposed for the self-assembly of the molecules within the mesophases. The imidazolium head groups and the iodide counterions were found to adopt a peculiar orientation in the central part of the columns of the hexagonal columnar phases. The enantiotropic cubic phase shown by the 1,3-dimethyl-2-[3,4-bis(pentadecyloxy)phenyl]imidazolium iodide salt has a multicontinuous Pm ̄3m structure. To the best of our knowledge, this is the first example of a thermotropic cubic mesophase of this symmetry.

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A new class of double alkyl-substituted, liquid crystalline imidazolium ionic liquids—a unique combination of structural features, viscosity effects, and thermal properties

Cited by 77 publications

References 20 publications

Surface Science and Model Catalysis with Ionic Liquid‐Modified Materials

Surface Science and Model Catalysis with Ionic Liquid‐Modified Materials

Ordering and Phase Transitions in Ionic Liquid‐Crystalline Films

T‐Shaped Ionic Liquid Crystals Based on the Imidazolium Motif: Exploring Substitution of the C‐2 Imidazolium Carbon Atom

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