Sulfur K-edge X-ray Absorption Spectroscopy and Time-Dependent Density Functional Theory of Dithiophosphinate Extractants: Minor Actinide Selectivity and Electronic Structure Correlations.
The dithiophosphinic acid HSP(o-CFCH) is known to exhibit exceptionally high extraction selectivities for trivalent minor actinides (Am and Cm) in the presence of trivalent lanthanides. To generate insight that may account for this observation, a series of [PPh][SPR] complexes, where R = Me (1), Ph...
| Publicado en: | Journal of the American Chemical Society Vol. 134; no. 35; pp. 14408 - 14423 |
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| Autores principales: | , , , , , , |
| Formato: | Artículo |
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American Chemical Society
9/5/2012
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| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=79924200&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 79924200 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 9/5/2012 vid: 134 iid: 35 pid: 997 pub: American Chemical Society artinfo: ui: 79924200 10.1021/ja303999q ppf: 14408 ppct: 15 formats: tig: atl: Sulfur K-edge X-ray Absorption Spectroscopy and Time-Dependent Density Functional Theory of Dithiophosphinate Extractants: Minor Actinide Selectivity and Electronic Structure Correlations. aug: au: Daly, Scott R. Keith, Jason M. Batista, Enrique R. Boland, Kevin S. Clark, David L. Kozimor, Stosh A. Martin, Richard L. affil: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States su: Density functionals Actinide elements Electronic structure Statistical correlation Rare earth metals Sulfur X-ray absorption spectra Aryl group sug: subj: Density functionals Actinide elements Electronic structure Statistical correlation Rare earth metals Sulfur X-ray absorption spectra Aryl group ab: The dithiophosphinic acid HSP(o-CFCH) is known to exhibit exceptionally high extraction selectivities for trivalent minor actinides (Am and Cm) in the presence of trivalent lanthanides. To generate insight that may account for this observation, a series of [PPh][SPR] complexes, where R = Me (1), Ph (2), p-CFCH (3), m-CFCH (4), o-CFCH (5), o-MeCH (6), and o-MeOCH (7), have been investigated using sulfur K-edge X-ray absorption spectroscopy (XAS) and time-dependent density functional theory (TDDFT). The experimental analyses show distinct features in the spectrum of S2P(o-CFCH)- (5) that are not present in the spectrum of 4, whose conjugate acid exhibits reduced selectivity, or in the spectra of 2 and 3, which are anticipated to have even lower separation factors based on previous studies. In contrast, the spectrum of 5 is similar to those of 6 and 7, despite the significantly different electron-donating properties associated with the o-CF, o-Me, and o-OMe substituents. The TDDFT calculations suggest that the distinct spectral features of 5-7 result from steric interactions due to the presence of the ortho substituents, which force the aryl groups to rotate around the P-C bonds and reduce the molecular symmetry from approximately C2v in 2-4 to C in 5-7. As a consequence, the change in aryl group orientation appears to make the ortho-substituted SPR- anions "softer" extractants compared with analogous Ph-, p-CFCH-, and m-CFCH-containing ligands (2-4) by raising the energies of the sulfur valence orbitals and enhancing orbital mixing between the SP molecular orbitals and the aryl groups bound to phosphorus. Overall, we report that sulfur K-edge XAS experiments and TDDFT calculations reveal unique electronic properties of the S2P(o-CFCH)- anion in 5. These results correlate with the special extraction properties associated with HS2P(o-CFCH), and suggest that ligand K-edge XAS and TDDFT can be used to guide separation efforts relevant to advanced fuel cycle development. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2012 holdings: @attributes: islocal: N |
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