Lanthanide dithiophosphinates

XAFS data for complexes of Cm with the HC301 extractant indicate only sulfur donation to the metal in the inner sphere of coordination. HC301 forms 3 1 complexes with the trivalent actinides and are coordinated in a bidentate mode as seen in Figure 91. Data indicates a hexacoordinate structure that resembles Z>3 symmetry in lanthanide dithiophosphinic acid complexes. 

Boehme, C., Wipff, G. 2001. The energetic and structural effects of steric crowding in phosphate and dithiophosphinate complexes of M3+ lanthanide cations. A computational study. Chem. Eur. J. 1 1398-1407. 

Jarvinen, G., Barrans, R., Schroeder, N. et al. 1994. Selective extraction of trivalent actinides from lanthanides with dithiophosphinic acids and tributylphosphate. American Chemical Society, San Diego, CA, March. LA-lJR-94-4350. 

Chen, J., Jiao, R., Zhu, Y. 1997. A cross-flow hot test for separating Am from fission product lanthanide by bis(2,4,4-trimethylpentyl)dithiophosphinic acid. Radiochim. Acta 76 (3/4) 129-130. 

Jensen, M.P., Bond, A.H., Rickert, P.G., Nash, K.L. 2002. Solution phase coordination chemistry of trivalent lanthanide and actinide cations with bis(2,4,4-trimeth-ylpentyl)dithiophosphinic acid. Journal of Nuclear Science and Technology (S3) 255-258. 

Modolo, G., Odoj, R. 1998. The separation of trivalent actinides from lanthanides by dithiophosphinic acids from HN03 acid medium. Journal of Alloys and Compounds 271-273 248-251. 

B. Coupez, C. Boehme, and G. Wipff. Importance of interfacial phenomena and synergistic effects in lanthanide cation extraction by dithiophosphinic ligands A molecular dynamics study. J. Phys. Chem. B, 107(35) 9484-9490, 2003. 

G. Modolo and S. Nabet. Thermodynamic study on the synergistic mixture of bis(chlorophenyl) dithiophosphinic acid and tris(2-ethylhexyl) phosphate for separation of actinides(iii) from lanthanides(iii). Solvent Extr. IonExch., 23(3) 359-373, 2005. 

Cyanex 301 One of the solvent extraction processes, used together with UREX, for separating the components of used nuclear fuel. This process uses a complex phosphinic acid, [bis(2,4,4-trimethylpentyl)dithiophosphinic acid], made by Cytec Industries, Canada. Its purpose is to separate americium, curium, and lanthanide fission products from the other components. 

Lanthanide-actinide separation was also attempted by HFSLM (operated in the nondispersive extraction mode) method using diphenyldithiophosphinic acid derivatives. Geist et al. have employed a synergistic mixture of bis(chlorophenyl)-dithiophosphinic acid and TOPO in a hollow fiber module for the lanthanide-actinide separation [168]. About 99.99% Am... 

Geist, A., Weigh M., and Gompper, K., Minor actinide partitioning hy hquid-hquid extraction using a synergistic mixture of his (chlorophenyl)dithiophosphinic acid and TOPO in a hollow fibre module for americium(III) and lanthanide(ni) separation. Sep. Sci. Tech., 2002, 37 3369-3390. 

Despite this stoichiometry ambiguity, both studies suggest a high selectivity for trivalent actinides over lanthanides by dithiophosphinic acids. " ... 

Cyanex-301 (bis(2,4,4-trimethyl pentyl) dithiophosphinic acid) has been extensively studied for lanthanide-actinide separation, either alone or in the presence of synergists [62,63], Solvent extraction studies using Cyanex-301 had indicated the following two-phase extraction equilibria for the extraction of trivalent lanthanides and actinides from aqueous nitrate medium [63] ... 

Cyanex-301 system. The sulfur type soft-donor extractant, thiophosphoric acid has potential for selective separation of trivalent actinides from lanthanides (Musikas 1985). Zhu et al. (Zhu 1995 Zhu et al. 1996) developed dithiophosphinic acid type extractant, Cyanex-301... 

Yttrium, Lanthanum and the Lanthanides. P NMR spectroscopy has been used to study complexation of La " by (4-02NC6H40)2P02H and (MeO)(4-02NC6H40)P02H. C and N NMR spectroscopy has been used to study complex formation between [SCN] andPr + and Nd. P chemical shifts of di(chlorophenyl)dithiophosphinic acid correlate quantitatively with the extrac-tability of Am and Eu ". ... 

G. Jarvinen et al "Selective Extraction of Trivalent Actinides from Lanthanides with Dithiophosphinic Acids and Tributylphosphate." in Separations off Elements, 1994, K. L. Nash G. R. Choppin Ed. Plenum Press, New York pp 43-62. 

Pinkerton and coworkers reported another method for separating the contact shifts and evaluating the hyperfine coupling constant A for P in NMR studies of a series of tetrakis lanthanide complexes derived from dithiophosphinates, [R S2P(CH3)2 4] (Spiliadis and Pinkerton 1982) and esters of dithiophosphoric acid, [R (XO)2PS2 4] ... 

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