4 ’ - Dp - Ms - 68 - 29 Tri - 2 - Propyl Phospiiate - Lanthanide Nitrate Complexes

Tri-2-propyl phosphate (T2PP) reacts with lanthanide nitrates to form two series of solid complexes, Ln(N03)3”3T2PP and Ln’(N03)3.2T2PP.H20,where Ln includes all lanthanides and Ln’ only Tb through Lu. These complexes were characterized by elemental analyses. X-ray diffraction patterns showed a single structure for each series, and infrared spectra showed that both nitrate and T2PP ligands were coordinated with lanthanide ions, Absorption, proton magnetic resonance (PMR), and infrared spectra demon3T2PP in CH2C1 solution to Yb(N03)3”2T2PP strated the dissociation of Yb(N03)3. and T2PP; co~lexes of other spectra to dissociate in the in CH2C12 solution yielded a small lanthanide ions (Tb-Lu) were shown by infrared same fashion. Dissolution of Ln’(N03)3.2T2PP.H20 mixture of Ln’(N03)3”3T2PP and Ln’(N03)3”2T2PP in solution and a precipitate of Ln’(N03)3”6H20. The relative stabilities of the different species are discussed in terms of a model where ligand-ligand repulsive forces increase with decreasing Ln 3+ size (or increasing Z) more rapidly than ion-ligand attractive forces. The increase in frequency of vibrational bands due to coordinated P-O and Y-O is shown to be consistent with this model.