Solvation of UCl62- anionic complex by MeBu3N+, BuMe2IM+, and BuMeIm(+) cations
Abstract
The complexes [MeBu3N](2)[UCl6] and [BuMe2IM](2)[UCl6] were characterized in the solid state and in solution of [MeBu3N][Tf2N], [BuMe(2)Im][Tf2N], and [BuMeIm][Tf2N] room-temperature ionic liquids using single-crystal XRD, EXAFS, electrochemistry, UV-visible absorption spectroscopy, and NMR. In the solid state and in solution, the existence of hydrogen bonding between the UCl62- complex and the ionic liquid cations was revealed by these techniques. The MeBu3N+ cation interacts with UCl62- via the protons on the alpha-carbon atoms of nitrogen. The protons of the imidazolium ring account for the interaction between the BuMe2IM+ cation and the UCl62- anion. For the BuMeIm(+) cation the major interaction was confirmed between the most acidic proton on C(2) and the chlorides of UCl62-. The experimental results also show that the intensity of the interaction between the UCl62- anion and the cation varies with the ionic liquid cation in the following order: MeBu3N+ approximate to BuMe(2)Im(+) << BuMeIm(+).