Solubility, dissociation and complexation with Nd(III) and Th(IV) of oxine, thenoyltrifluoroacetone and 1,10-phenanthroline in 5.0 m NaCl.
Equilibria in the system of Nd(III) and Th(IV) with 8-hydroxyquinoline (oxine), thenoyltrifluoroacetone (HTTA) and 1,10-phenanthroline (phen) in 5.0 m NaCl solution have been investigated by spectroscopy and potentiometry. The solubility and deprotonation constants of the three organics were measured to be: pK(s) = 3.09 +/- 0.01, pK(a1) = 5.82 +/-0.02, pK(a2)= 10.00 +/-0.01 for oxine; pK(s) = 2.49 +/- 0.01, pK(a1) = 6.47 +/-0.03 for HTTA; pK(s) = 2.86 +/- 0.02, pK(a2) = 5.82 +/- 0.05 for phen. The stabilities of the corresponding metal complexes are in the order M(oxine) > M(TTA) > M(phen), where M = Nd(III), Th(IV). For all three organic ligands, the Th(IV) complexation is stronger than that of Nd(III).
Xia
Y X
YX
Chen
J F
JF
Choppin
G R
GR