Abstract
A solution of imidazole in dichloromethane developed blue color immediately by an addition of a solution of tetracyanoethylene in the same solvent at the temperature of lower than 0°. The color turned to yellowish brown when the temperature of the mixture was allowed to rise to higher than 0°. A mixing of both solutions at room temperature produced yellowish brown solution, directly. The mixture separated reddish brown crystals when it was stand at room temperature for about 30 min. The absorption maxima at 400 and 418 mμ of the crystals were proved to be attributable to 1, 1, 2, 3, 3-pentacyanopropenide anion, and this absorption spectrum was shown to be almost identical with that of the reaction mixture mixed at room temperature. 4(5)-Methyl-, 4(5)-phenyl- and 4, 5-diphenylimidazole gave similar results. The chemical structures of these crystals were clarified as imidazolium and substituted imidazolium 1, 1, 2, 3, 3-pentacyanopropenide from the results of elemental analyses, infrared spectra, nuclear magnetic spectra, titrations with sodium hydroxide solution, and from the detections of imidazole and imidazole derivatives on thin-layer chromatogram developed by a basic solvent.
