SYNTHESIS AND CHARACTERIZATION OF PLUTONIUM(IV), URANIUM(VI), THORIUM(IV) AND NEODYMIUM(III) NITRATE COMPLEXES WITH BIDENTATE ORGANOPHOSPHORUS LIGANDS

Solid adducts of actinide and lanthanide nitrates of the type [M(NO3)( n)(X)(y)], where M = Pu4+, UO22+, Th4+ and Nd3+; n = 2 for UO22+, 3 fo r Nd3+ and 4 for Th4+ and Pu4+; y = 1 for UO22+, 1.5 for Th4+ and 2 fo r Pu4+ and Nd3+; and X = dihexyl N,N-diethylcarbamoylmethylphosphonate (DHDECMP) or yl(phenyl)(N,N-diisobutylcarbamoylmethyl)phosphine oxide (CMPO), were isolated and purified by a solvent extraction route from benzene. These compounds have been characterized by elemental analyse s, and their melting points. The IR and visible absorption spectra of these complexes indicate that they are O-bonded. The extractant in all the complexes acts as a bidentate ligand whereas the nitrate ion acts as a bidentate group in the Th4+ UO22+ and Nd3+ complexes but in the case of the Pu4+ complexes one of the nitrate ions probably is acting as monodentate ligand. A slight upfield shift of phenyl, methyl and me thylene protons around phosphoryl and carbamoyl oxygens in the H-1 NMR spectra of the uranium, thorium and neodymium complexes, as compared to the pure ligand, further reaffirms the bidentate nature of CMPO. Th ermal studies of the uranyl and thorium complexes are reported.