Crystal structure of hydrates of imidazolium salts

Kohmoto, Shigeo; Okuyama, Shinpei; Nakai, T.; Takahashi, Masahiro; Kishikawa, Keiki; Masu, Hyuma; Azumaya, Isao

doi:10.1016/j.molstruc.2011.05.032

Cited by 9 publications

(7 citation statements)

References 40 publications

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“…There was no interdigitation between the alkyl chains in [ 1-C12 ][PF 6 ] and [ 1-C18 ][PF 6 ], and therefore, an extended bilayer structure was formed . Several imidazolium salts and other compounds bearing trisubstituted benzene moieties with long alkyl chains ( n = 12–14) exhibit similar lamellar structures in the solid state, which lead to either an extended bilayer or interdigitated structure. , Similar to the present case, compounds bearing trisubstituted benzene moieties with an intermediate chain length ( n ∼ 6) are reported to have bent alkyl chains …”

Section: Resultssupporting

confidence: 73%

Thermal Properties and Crystal Structures of Ionic Liquids from Ruthenium Sandwich Complexes with Trialkoxybenzene Ligands: Effects of Substituent Positions and Alkyl Chain Lengths

Ueda

Mochida

2015

Organometallics

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A series of ionic liquids containing [Ru(C 5 H 5 )-(arene)] + , where the arene ligands are 1,2,3-C 6 H 3 (OC n H 2n+1 ) 3 and 1,3,5-C 6 H 3 (OC n H 2n+1 ) 3 (n = 6, 12, and 18), were synthesized. The counteranions were PF 6 and FSA (bis-(fluorosulfonyl)amide). The melting points of the PF 6 and FSA salts were 33−93 °C and −18−62 °C, respectively. In the PF 6 salts, the melting points of the 1,3,5-derivatives were lower than those of the 1,2,3-derivatives by 28−55 °C, whereas no such tendency was observed in the FSA salts. X-ray crystallography showed the formation of lamellar structures in the PF 6 salts of the 1,2,3-derivatives in the solid state. In these crystals, cation−anion pairs via C Cp H•••F H-bond-like interactions were commonly observed. Several 1,3,5-derivatives showed metastable phases with lower melting points than the stable phases. The salts of the 1,2,3-derivative (n = 2) were also synthesized and characterized.

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Section: Resultssupporting

confidence: 73%

Thermal Properties and Crystal Structures of Ionic Liquids from Ruthenium Sandwich Complexes with Trialkoxybenzene Ligands: Effects of Substituent Positions and Alkyl Chain Lengths

Ueda

Mochida

2015

Organometallics

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“…Hydrogen bonding between the halide anions and the water molecules stabilizes the smectic layers. This is supported by the single-crystal structures of several long-chain imidazolium, benzimidazolium, and ammonium salts, ,,,− from which it is clear that cohesion in the solid state, and possibly, by extension, in the LC state, is not necessarily ensured by the electrostatic interactions alone . In this context, it is noteworthy that the Weiss group found that addition of at least 1 molar equivalent of water or MeOH to P , P , P -tris( n -alkyl)- P -methylphosphonium halides induces LC properties in some cases, and enhances the mesophase temperature range and lowers the melting point in some other cases. − , These general findings on the importance of hydrogen-bonding interactions for the induction and stabilization of ILC smectic phases will be further discussed in section .…”

Section: Imidazolium-based Ionic Liquid Crystalsmentioning

confidence: 93%

“…No discrete π−π stacking distance has been observed by PXRD in any of the columnar phases formed by simple taper-shaped amphiphiles. It should also be mentioned that the single-crystal structure of the chloride salt 53-Cl-12•H 2 O consists of stacked bilayers, not of supramolecular cylinders; 571 apparently, the thermal motion of the molten alkyl chains in the mesophase causes the transition from a lamellar to a phase-segregated cylinder structure. Macroscopic alignment of the supramolecular columns parallel to a supporting glass slide could be achieved by shearing of a polydomain sample between two microscopy glass slides (i.e., rubbing treatment of the glass slides was not necessary), and results in 1D ion-conductive channels formed by the ionic cores of the columns (Figure 22).…”

Section: Taper-shaped Imidazolium-based Mesogensmentioning

confidence: 99%

Ionic Liquid Crystals: Versatile Materials

et al. 2016

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This Review covers the recent developments (2005-2015) in the design, synthesis, characterization, and application of thermotropic ionic liquid crystals. It was designed to give a comprehensive overview of the "state-of-the-art" in the field. The discussion is focused on low molar mass and dendrimeric thermotropic ionic mesogens, as well as selected metal-containing compounds (metallomesogens), but some references to polymeric and/or lyotropic ionic liquid crystals and particularly to ionic liquids will also be provided. Although zwitterionic and mesoionic mesogens are also treated to some extent, emphasis will be directed toward liquid-crystalline materials consisting of organic cations and organic/inorganic anions that are not covalently bound but interact via electrostatic and other noncovalent interactions.

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“…For amphiphilic molecules of this kind, it can be assumed that, due to nanosegregation and strong electrostatic interactions, the cationic moieties and the [N(CN) 2 ] − anions segregate into ionic sublayers with a head‐to‐head arrangement of the ionic headgroups (see Figure a) . The alkyl chains are homogeneously distributed on either side of the ion‐rich layers, which results in the alternation of ionic and aliphatic sublayers.…”

Section: Resultsmentioning

confidence: 93%

Dicyanamide Salts that Adopt Smectic, Columnar, or Bicontinuous Cubic Liquid‐Crystalline Mesophases

Park

Goossens

Shin

et al. 2018

Chemistry A European J

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Although dicyanamide (i.e., [N(CN) ] ) has been commonly used to obtain low-viscosity, halogen-free, room-temperature ionic liquids, liquid-crystalline salts containing such anions have remained virtually unexplored. Here we report a series of amphiphilic dicyanamide salts that, depending on their structures and compositions, adopt smectic, columnar, or bicontinuous cubic thermotropic liquid-crystalline mesophases, even at room temperature in some cases. Their thermal properties were explored by polarized light optical microscopy, differential scanning calorimetry, thermogravimetric analysis (including evolved gas analysis), and variable-temperature synchrotron X-ray diffraction. Comparison of the thermal phase characteristics of these new liquid-crystalline salts featuring "V-shaped" [N(CN) ] anions with those of structural analogues containing [SCN] , [BF ] , [PF ] , or [CF SO ] anions indicated that not only the size of the counterion but also its shape should be considered in the development of mesomorphic salts. Collectively, these discoveries may be expected to facilitate the design of thermotropic ionic liquid crystals that form inverted-type bicontinuous cubic and other sophisticated liquid-crystalline phases.

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Crystal structure of hydrates of imidazolium salts

Cited by 9 publications

References 40 publications

Thermal Properties and Crystal Structures of Ionic Liquids from Ruthenium Sandwich Complexes with Trialkoxybenzene Ligands: Effects of Substituent Positions and Alkyl Chain Lengths

Thermal Properties and Crystal Structures of Ionic Liquids from Ruthenium Sandwich Complexes with Trialkoxybenzene Ligands: Effects of Substituent Positions and Alkyl Chain Lengths

Ionic Liquid Crystals: Versatile Materials

Dicyanamide Salts that Adopt Smectic, Columnar, or Bicontinuous Cubic Liquid‐Crystalline Mesophases

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