Dissolution of Metal Salts in Bis(trifluoromethylsulfonyl)imide-Based Ionic Liquids: Studying the Affinity of Metal Cations Toward a “Weakly Coordinating” Anion

摘要

Despite the weakly coordinating ability of the bis(trifluoromethylsulfonyl)imide anion ([Tf2N]−) the corresponding ionic liquids (ILs) are able to dissolve relevantudamounts of metal salts having the same anion, M[Tf2N]x. To better understand the metal dissolution process we evaluated the interaction ability of a set of metal cations (Y(III), Al(III), Co(II), Ni(II), Cu(II), Zn(II), Ag(I), Li(I), and Na(I)) toward the [Tf2N]− anion measuring the relative aptitude to give the corresponding anionic monocharged complex, [M(Tf2N)x+1]− using the ESI-MS technique. UV−vis and NMR measurements were carried out to verify the consistence between the liquid and the gas phase. Density functional theory calculations have been used to identify the metal-containing species and determine their relative stability. An interesting correlation between interaction ability and chemical properties (Lewis acidity) was found