| Abstrakt: |
Hydrated lanthanide(iii) chlorides, LnCl3·xH2O (Ln = La, Pr, Nd, Sm, Eu, Gd; x = 6–7) readily dissolve in the low melting ionic liquid 1-ethyl-3-methylimidazolium chloride ([C2mim]Cl) in an open vessel at 110 °C, and upon cooling crystallize as the anhydrous [C2mim]3[LnCl6]. The crystal structures exhibit a face-centered packing arrangement of the [LnCl6]3− anions, with the cations located as slip aligned pairs in the void spaces which participate in hydrogen-bonding to chlorides. A second crystalline form of the Gd3+ complex, GdCl3(OH2)4·2([C2mim]Cl), was isolated when the above reaction was conducted in a sealed system. For comparison, a third Gd3+ compound was grown from the ionic liquid 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) using the same unsealed conditions as above, and was found to be [C4mim]3[GdCl6]. This compound exhibits a different packing arrangement to that observed for the [C2mim]+ analogs. Based on these findings, ILs would appear to offer new crystallization process options based on their often high thermal stabilities and low to negligible vapor pressures. [ABSTRACT FROM AUTHOR] |
