1-Carboxymethyl-3-methyl-1H-imidazol-3-ium chloride 2-(3-methyl-1H-imidazol-3-ium-1-yl)acetate monohydrate: a crystal stabilized by imidazolium zwitterions

Abstract

The title compound, C6H9N2O2(+)·Cl(-)·C6H8N2O2·H2O, contains one 2-(3-methyl-1H-imidazol-3-ium-1-yl)acetate inner salt molecule, one 1-carboxymethyl-3-methyl-1H-imidazol-3-ium cation, one chloride ion and one water molecule. In the extended structure, chloride anions and water molecules are linked via O-H···Cl hydrogen bonds, forming an infinite one-dimensional chain. The chloride anions are also linked by two weak C-H···Cl interactions to neighbouring methylene groups and imidazole rings. Two imidazolium moieties form a homoconjugated cation through a strong and asymmetric O-H···O hydrogen bond of 2.472 (2) Å. The IR spectrum shows a continuous D-type absorption in the region below 1300 cm(-1) and is different to that of 1-carboxymethyl-3-methylimidazolium chloride [Xuan, Wang & Xue (2012). Spectrochim. Acta Part A, 96, 436-443].

Hydrogen bonds in the crystal structure of hydrophobic and hydrophilic COOH-functionalized imidazolium ionic liquids

“…32 We also devoted ourselves to determining the crystal structure of 1-carboxymethyl-3methylimidazolium chloride and its properties by a combination of experiments and DFT calculations. 33,34 As for the hydrophobic COOH-functionalized ILs, there is little research except for the 1-carboxymethyl-3-methylimidazolium TFSI. 21 Obviously, systematic studies are necessary to design them and control their physical properties because the dependence of the properties on the structure is still unclear.…”