Abstract
Complexation of trivalent lanthanides and actinides was studied in a room temperature ionic liquid (RTIL) using five N-pivot tripodal diglycolamide ligands (LI–LV) having different structural features, viz. spacer lengths and substituents. The nature of the metal/Ligand complex changed with the substitution of N atom near the tripodal platform from ML with LIII and LIV to ML2 with LI, LII and LV (where M = Eu3+/Nd3+/Am3+). With 0.2 mmol/L ligands, the distribution ratio of Am3+ at 1 m HNO3 followed the order: LI (210) > LII (42) > LIII (2.1) > LV (0.7) > LIV (0.2). The formation constants between Nd3+ and the ligands (log βML,ML2) followed an identical order, viz. LI > LII > LIII > LV > LIV. The extraction of Am3+ or Eu3+ with all the ligands followed a cation-exchange extraction mechanism, which is in sharp contrast to the results obtained in a molecular solvent (n-dodecane), where a solvation extraction mechanism prevalied. Luminescence studies on the Eu3+ extract in RTIL confimed the absence of water molecules in the inner coordination sphere of the complex. EXAFS studies indicated that all three DGA arms were binding to the Eu3+ cation.
Original language | English |
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Pages (from-to) | 191-199 |
Number of pages | 9 |
Journal | European journal of inorganic chemistry |
Volume | 2020 |
Issue number | 2 |
DOIs | |
Publication status | Published - 16 Jan 2020 |
Keywords
- UT-Hybrid-D
- Complexation
- Luminescence
- Separation
- Stability constants
- Actinides