A convenient method for preparing rigid-core ionic liquid crystals

Abstract

SummaryAn efficient, solvent free method for the N-arylation of imidazole by 1-(dodecyloxy)-4-iodobenzene using Cu(II)-NaY as catalyst and K2CO3 as base is reported. By this synthetic approach, mesomorphic 3-[4-(dodecyloxy)phenyl]-1-methyl-1H-imidazol-3-ium iodide was synthesized in a two-step procedure, and its mesomorphism has been fully investigated by polarised optical microscopy, differential scanning calorimetry and X-ray diffraction. In addition its lamellar crystal structure, electrochemical behaviour and UV (absorption and emission) properties are reported.

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

“…[1,42,48,50] The calculated values of A M,limit are larger than those reported for 1-[3,4-bis(hexyloxy)benzyl]-3methylimidazolium halides (ca. [1,42,48,50] The calculated values of A M,limit are larger than those reported for 1-[3,4-bis(hexyloxy)benzyl]-3methylimidazolium halides (ca.…”

“…Thus,t he breakdown of the ionic sublayersi nt he SmA phases of 1 and 2 (which feature the same alkyl chain volumep er molecule) resultsi nc learing to the isotropic liquid state and is governed by the temperature-dependent molecular cross-sectional area. [1,42,48,50] The calculated values of A M,limit are larger than those reported for 1-[3,4-bis(hexyloxy)benzyl]-3methylimidazolium halides (ca. 52.5 2 ) [48] and 1-(4-dodecyloxy-benzyl)-3-methylimidazolium salts (ca.…”

“…Larger ionic headgroupst ypically result in smaller smecticl ayer spacings due to increased chain foldinga nd interdigitation to achieve ab alance between the area of the cationic headgroup/anion assembly that is projected onto the smecticl ayer planesa nd the cross-sectional area(s)o ft he respective alkyl chain(s) attachedt ot he cation. The increasei nA M as af unction of temperature (Figure 7a)w as attributed to the known [49,50] "spreading" of the ionic sublayersw ith increasing temperature, ap rocess that is accompanied by increased folding of the alkyl chains, as reflected in the temperature evolutions of the aliphatic and ionic sublayer thicknesses (see FigureS16). This result suggested to us that the bulkier ÀN + (C 2 H 5 ) 3 headgroups may cause the ionic sublayerst oe xpand in lateral as well as longitudinal directions due to "rippling" or "undulation" (Figure 6a).…”

1-(4-Alkyloxybenzyl)-3-methyl-1H-imidazol-3-ium organic backbone: A versatile smectogenic moiety

“…(On the basis of previous results [32], the calculated molecular area S 0 and ionic sublayer thickness d c 0 for flat layers are estimated to be 54 Å 2 and 10 Å, respectively. S and d c values close to the low limit are of about 33 Å 2 and 17 Å.…”

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

“…[19][20][21][22][23][24][25] Kouwer and Swager recognised that the imidazolium fragment is a polarisable rigid group that is suitable as part of a mesogenic core rather than being placed at one end of a flexible alkyl chain. [26] However, the mesomorphism of ionic mesogens, wherein the imidazolium group is an integral part of the rigid core, remained virtually unexplored until very recently when reports appeared in the literature about 1-aryl-3-alkylimidazolium salts [26][27][28][29] and 1,3-diarylimidazolium salts. [30,31] However, no examples exist of 2-arylsubstituted imidazolium ionic liquid crystals (i.e., with a substituted aryl group directly connected to the carbon atom in the 2-position of the imidazolium ring).…”