Abstract
The stability of yttrium complexes, HPi+[Y(TTA)4]- and Y(TTA)3·2H2O (HPi+: γ-picolinium cation, TTA: thenoyltrifluoroacetonate anion) in basic acetone solution was studied by PMR spectroscopy. The chemical shift (δ) of α- and β-protons of γ-picolinium considerably shifted towards higher field and approached to the values for free γ-picoline, as either TBP (tributylphosphate) or γ -picoline was added to the acetone solution of HPi+[Y(TTA)4]-. On the other hand, the δ values for all protons of TTA in the complex slightly shifted towards lower field with increasing of TBP and towards higher field as γ-picoline was added. Because of larger δ values for free TTA than for the complexed TTA, the following reactions seemed to occur:
HPi+[Y(TTA)4]-+nTBP_??_Y(TTA)3·nTBP+
HTTA+Pi
HPi+[Y(TTA)4]-_??_Y(TTA)3+HTTA+Pi
These results are well interpreted in terms of the difference between the synergistic effects of the above mentioned organic bases in the solvent extraction. The PMR spectrum of Y(TTA)3·2H2O was not altered by these bases except for the position of water peak, which was shifted by the bases towards higher field as the result of exchange interactions. In the IR spectrum of HPi+[Y(TTA)4]- (in a KBr disk), the stretching vibration of γ-picolinium, N+-H, was observed at 2850 cm-1.
