Room temperature ionic liquids (RTILs) can potentially be used to replace conventional organic solvents in separations of actinides and lanthanides. Understanding lanthanide/actinide solvation and coordination chemistry in RTILs will aid in designing more effective separation procedures. In this study we have used Raman, ATR-FTIR, and NMR spectroscopies to examine La(III) speciation and coordination chemistry in solutions of 1-ethyl-3-methlyimidazolium bis(triflouromethylsulfonyl)imide (EMIM-Tf2N) containing perchlorate, water, and tributylphosphine oxide (TBPO) or tributylphosphate (TBP). Our results show that perchlorate and water form complexes with La(III) in EMIM-Tf2N, and that these are displaced by the more strongly complexing organophosphorus ligands. We have also investigated the interactions between EMIM-Tf2N, the organophosphorus ligands, and water. Our results suggest that TBP and TBPO interact both with water and with protons on the EMIM+ imidazolium ring through hydrogen bonding. We intend to investigate the effects of La(III) on these interactions, as well a examine the effect of water on La(III)-TBP and -TBPO complexes using variable temperature 1H, 2H, and 31P NMR spectroscopies.

Lanthanum(III) complexes with tributylphosphate and tributylphosphine oxide in an imidazolium-based room temperature ionic liquid

248th National Meeting (2014)

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