Dialkylimidazolium liquid crystal

Among the earliest ionic liquids for which single-crystal characterisation of polymorphs has been reported are 1,3-dialkylimidazolium chlorides and bromides [230, 566]. Monoclinic and orthorhombic forms of [C4inim]Cl are associated with differences in butyl conformation, with a conputational study [567] suggesting that the free energy difference associated with a single... 

N., iVjiV -Dialkylimidazolium chloroplatinate(II), chloroplatinate(IV), and chloroiridate(IV) salts and an iV-heterocyclic carbene complex of platinum(II) Synthesis in ionic liquids and crystal structures, Inorg. Chem. 40 (4), 795-800 (2001). 

Ionic liquids have been known for nearly a century the first to be discovered was ethylammonium nitrate, CH3CH2NH3" N03, with a melting point of 12 °C. More generally, however, the ionic liquids in use today are salts in which the cation is unsymmetrical and in which one or both of the ions are bulky so that the charges are dispersed over a large volume. Both factors minimize the crystal lattice energy and disfavor formation of the solid. Typical cations are quaternary ammonium ions from heterocyclic amines, either 1,3-dialkylimidazolium ions, JV-alkylpyridinium ions, or ring-substituted AT-alkylpyridinium ions. 

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