Ambient temperature imidazolium-based ionic liquids with tetrachloronickelate(II) anions

Deep blue tetrachloronickelate(II) salts of 1-alkyl-3-methylimidazolium cations [Cnmim]+ with intermediate chain lengths (n = 5, 7, 8 and an n = 4/6 mixture) have been prepared from imidazolium chlorides and NiCl2. They are liquid at ambient temperatures (ca. 20 °C) and above, and display viscosities and thermal stability comparable to related [BF4]− compounds. The similarities may reflect the compensating effects of the dinegative charge of the [NiCl4]2− ion and its larger size.

Graphical abstractTetrachloronickelate(II) salts of 1-alkyl-3-methylimidazolium cations with intermediate chain lengths (C5, C7, C8 or a C4/C6 mixture) are liquid at room temperature (20 °C) and above. Despite the dinegative charge on the anion, their viscosities and thermal stabilities are similar to those of related [BF4]− compounds.Figure optionsDownload full-size imageDownload as PowerPoint slide