Switchable phase behavior of [HBet][Tf2N]-H2O upon neodymium loading: implications for lanthanide separations

Task-specific ionic liquids (TSILs) present an opportunity to replace traditional organic solvents for metal dissolution or separation. To date, a thorough investigation of the physical properties of biphasic TSIL-H(2)O systems and the effects of metal loading is lacking. In this work, the change in the liquid-liquid equilibrium of [HBet][Tf(2)N]-H(2)O upon the addition of Nd(III) is investigated by cloud-point measurements. The addition of Nd(III), drops the upper critical solution temperature by over 20 °C. Further investigation of the [HBet][Tf(2)N]-Nd(III) system led to the formation of single crystals of [Nd(2)(H(2)O)(8)(μ(2)-Bet)(2)(μ(3)-Bet)(2)][(Cl)(2)(Tf(2)N)(4)] from the TSIL phase.