Progressing From Disparity to Equity: Untangling the Complexities of Timely Care and the Rural Cancer Experience.

Richard L. Martin III, MD, MPH, and Stephen Schleicher, MD, MBA, share a perspective on rural cancer care.

Energy-Degeneracy-Driven Covalency in Actinide Bonding.

Evaluating the nature of chemical bonding for actinide elements represents one of the most important and long-standing problems in actinide science. We directly address this challenge and contribute a Cl K-edge X-ray absorption spectroscopy and relativistic density functional theory study that quantitatively evaluates An-Cl covalency in AnCl62- (AnIV = Th, U, Np, Pu). The results showed significant mixing between Cl 3p- and AnIV 5f- and 6d-orbitals (t1u*/t2u* and t2 g*/eg *), with the 6d-orbitals showing more pronounced covalent bonding than the 5f-orbitals. Moving from Th to U, Np, and Pu markedly changed the amount of M-Cl orbital mixing, such that AnIV 6d - and Cl 3p-mixing decreased and metal 5f - and Cl 3p-orbital mixing increased across this series.

Quantitative Evidence for Lanthanide-Oxygen Orbital Mixing in CeO2, PrO2, and TbO2.

Understanding the nature of covalent (band-like) vs ionic (atomic-like) electrons in metal oxides continues to be at the forefront of research in the physical sciences. In particular, the development of a coherent and quantitative model of bonding and electronic structure for the lanthanide dioxides, LnO2 (Ln = Ce, Pr, and Tb), has remained a considerable challenge for both experiment and theory. Herein, relative changes in mixing between the O 2p orbitals and the Ln 4f and 5d orbitals in LnO2 are evaluated quantitatively using O K-edge X-ray absorption spectroscopy (XAS) obtained with a scanning transmission X-ray microscope and density functional theory (DFT) calculations. For each LnO2, the results reveal significant amounts of Ln 5d and O 2p mixing in the orbitals of t2g (σ-bonding) and eg (π-bonding) symmetry. The remarkable agreement between experiment and theory also shows that significant mixing with the O 2p orbitals occurs in a band derived from the 4f orbitals of a2u symmetry (σ-bonding) for each compound. However, a large increase in orbital mixing is observed for PrO2 that is ascribed to a unique interaction derived from the 4f orbitals of t1u symmetry (σ- and π-bonding). O K-edge XAS and DFT results are compared with complementary L3-edge and M5,4-edge XAS measurements and configuration interaction calculations, which shows that each spectroscopic approach provides evidence for ground state O 2p and Ln 4f orbital mixing despite inducing very different core-hole potentials in the final state.

Exposome-Scale Investigations Guided by Global Metabolomics, Pathway Analysis, and Cognitive Computing.

Concurrent exposure to a wide variety of xenobiotics and their combined toxic effects can play a pivotal role in health and disease, yet are largely unexplored. Investigating the totality of these exposures, i.e., the "exposome", and their specific biological effects constitutes a new paradigm for environmental health but still lacks high-throughput, user-friendly technology. We demonstrate the utility of mass spectrometry-based global exposure metabolomics combined with tailored database queries and cognitive computing for comprehensive exposure assessment and the straightforward elucidation of biological effects. The METLIN Exposome database has been redesigned to help identify environmental toxicants, food contaminants and supplements, drugs, and antibiotics as well as their biotransformation products, through its expansion with over 700 000 chemical structures to now include more than 950 000 unique small molecules. More importantly, we demonstrate how the XCMS/METLIN platform now allows for the readout of the biological effect of a toxicant through metabolomic-derived pathway analysis, and further, artificial intelligence provides a means of assessing the role of a potential toxicant. The presented workflow addresses many of the methodological challenges current exposomics research is facing and will serve to gain a deeper understanding of the impact of environmental exposures and combinatory toxic effects on human health.

Increasing Colorectal Cancer Screening at an Urban FQHC Using iFOBT and Patient Navigation.

INTRODUCTION: Colorectal cancer is the second leading cause of cancer death in the United States. Black Americans suffer even higher incidence and death rates than the general population. Genetics and patient perceptions explain some of this difference, however, modifiable health care system factors such as lack of access to colon cancer screening also contribute. Partnering an academic health center with local community groups, we piloted a colorectal cancer screening program at a Federally Qualified Health Center (FQHC) serving predominately low socioeconomic status Black Americans. The program was designed to identify and remove barriers to screening and improve screening rates. METHOD: At a single center FQHC, we developed an outreach program centered around (1) patient and provider education, (2) immunochemical fecal occult blood test (iFOBT) distribution, and (3) patient navigation. We identified 402 eligible patients, of which 228 (56.7%) completed screening. RESULTS: Our 56.7% screening rate represented a twofold increase above prepilot levels at the clinic. Nine (4%) iFOBT returned positive. Three of these nine patients completed colonoscopy. Screening rates and follow through were higher under a single navigator model. CONCLUSIONS: Our academic-community partnership provided an effective, evidence based, and sustainable model for increasing colorectal cancer screening in a high risk, low resource community.

Covalency in lanthanides. An X-ray absorption spectroscopy and density functional theory study of LnCl6(x-) (x = 3, 2).

Covalency in Ln-Cl bonds of Oh-LnCl6(x-) (x = 3 for Ln = Ce(III), Nd(III), Sm(III), Eu(III), Gd(III); x = 2 for Ln = Ce(IV)) anions has been investigated, primarily using Cl K-edge X-ray absorption spectroscopy (XAS) and time-dependent density functional theory (TDDFT); however, Ce L3,2-edge and M5,4-edge XAS were also used to characterize CeCl6(x-) (x = 2, 3). The M5,4-edge XAS spectra were modeled using configuration interaction calculations. The results were evaluated as a function of (1) the lanthanide (Ln) metal identity, which was varied across the series from Ce to Gd, and (2) the Ln oxidation state (when practical, i.e., formally Ce(III) and Ce(IV)). Pronounced mixing between the Cl 3p- and Ln 5d-orbitals (t2g* and eg*) was observed. Experimental results indicated that Ln 5d-orbital mixing decreased when moving across the lanthanide series. In contrast, oxidizing Ce(III) to Ce(IV) had little effect on Cl 3p and Ce 5d-orbital mixing. For LnCl6(3-) (formally Ln(III)), the 4f-orbitals participated only marginally in covalent bonding, which was consistent with historical descriptions. Surprisingly, there was a marked increase in Cl 3p- and Ce(IV) 4f-orbital mixing (t1u* + t2u*) in CeCl6(2-). This unexpected 4f- and 5d-orbital participation in covalent bonding is presented in the context of recent studies on both tetravalent transition metal and actinide hexahalides, MCl6(2-) (M = Ti, Zr, Hf, U).

Oxidation and hydration of U3O8 materials following controlled exposure to temperature and humidity.

Chemical signatures correlated with uranium oxide processing are of interest to forensic science for inferring sample provenance. Identification of temporal changes in chemical structures of process uranium materials as a function of controlled temperatures and relative humidities may provide additional information regarding sample history. In this study, a high-purity α-U3O8 sample and three other uranium oxide samples synthesized from reaction routes used in nuclear conversion processes were stored under controlled conditions over 2-3.5 years, and powder X-ray diffraction analysis and X-ray absorption spectroscopy were employed to characterize chemical speciation. Signatures measured from the α-U3O8 sample indicated that the material oxidized and hydrated after storage under high humidity conditions over time. Impurities, such as uranyl fluoride or schoepites, were initially detectable in the other uranium oxide samples. After storage under controlled conditions, the analyses of the samples revealed oxidation over time, although the signature of the uranyl fluoride impurity diminished. The presence of schoepite phases in older uranium oxide material is likely indicative of storage under high humidity and should be taken into account for assessing sample history. The absence of a signature from a chemical impurity, such as uranyl fluoride hydrate, in an older material may not preclude its presence at the initial time of production. LA-UR-15-21495.

Synthesis and characterization of nitrogen-rich macrocyclic ligands and an investigation of their coordination chemistry with lanthanum(III).

Derivatives of the ligand 1,4,7,10-tetraazacyclododecane (cyclen) containing pendant N-heterocyclic donors were prepared. The heterocycles pyridine, pyridazine, pyrimidine, and pyrazine were conjugated to cyclen to give 1,4,7,10-tetrakis(pyridin-2-ylmethyl)-1,4,7,10-tetraazacyclododecane (L(py)), 1,4,7,10-tetrakis(3-pyridazylmethyl)-1,4,7,10-tetraazacyclododecane (L(pyd)), 1,4,7,10-tetrakis(4-pyrimidylmethyl)-1,4,7,10-tetraazacyclododecane (L(pyr)), and 1,4,7,10-tetrakis(2-pyrazinylmethyl)-1,4,7,10-tetraazacyclododecane (L(pz)), respectively. The coordination chemistry of these ligands was explored using the La(3+) ion. Accordingly, complexes of the general formula [La(L)(OTf)](OTf)2, where OTf = trifluoromethanesulfonate and L = L(py) (1), L(pyd) (2), L(pyr) (3), and L(pz) (4), were synthesized and characterized by NMR spectroscopy. Crystal structures of 1 and 2 were also determined by X-ray diffraction studies, which revealed 9-coordinate capped, twisted square-antiprismatic coordination geometries for the central La(3+) ion. The conformational dynamics of 1-4 in solution were investigated by variable-temperature NMR spectroscopy. Dynamic line-shape and Eyring analyses enabled the determination of the activation parameters for the interconversion of enantiomeric forms of the complexes. Unexpectedly, the different pendant N-heterocycles of 1-4 give rise to varying values for the enthalpies and entropies of activation for this process. Density functional theory calculations were carried out to investigate the mechanism of this enantiomeric interconversion. Computed activation parameters were consistent with those experimentally determined for 1 but differed somewhat from those of 2-4.

In silico prediction of MOFs with high deliverable capacity or internal surface area.

Metal-organic frameworks (MOFs) offer unprecedented atom-scale design and structural tunability, largely due to the vast number of possible organic linkers which can be utilized in their assembly. Exploration of this space of linkers allows identification of ranges of achievable material properties as well as discovery of optimal materials for a given application. Experimental exploration of the linker space has to date been quite limited due to the cost and complexity of synthesis, while high-throughput computational studies have mainly explored MOF materials based on known or readily available linkers. Here an evolutionary algorithm for de novo design of organic linkers for metal-organic frameworks is used to predict MOFs with either high methane deliverable capacity or methane accessible surface area. Known chemical reactions are applied in silico to a population of linkers to discover these MOFs. Through this design strategy, MOF candidates are found in the ten symmetric networks acs, cds, dia, hxg, lvt, nbo, pcu, rhr, sod, and tbo. The correlation between deliverable capacities and surface area is network dependent.

In silico design of porous polymer networks: high-throughput screening for methane storage materials.

Porous polymer networks (PPNs) are a class of advanced porous materials that combine the advantages of cheap and stable polymers with the high surface areas and tunable chemistry of metal-organic frameworks. They are of particular interest for gas separation or storage applications, for instance, as methane adsorbents for a vehicular natural gas tank or other portable applications. PPNs are self-assembled from distinct building units; here, we utilize commercially available chemical fragments and two experimentally known synthetic routes to design in silico a large database of synthetically realistic PPN materials. All structures from our database of 18,000 materials have been relaxed with semiempirical electronic structure methods and characterized with Grand-canonical Monte Carlo simulations for methane uptake and deliverable (working) capacity. A number of novel structure-property relationships that govern methane storage performance were identified. The relationships are translated into experimental guidelines to realize the ideal PPN structure. We found that cooperative methane-methane attractions were present in all of the best-performing materials, highlighting the importance of guest interaction in the design of optimal materials for methane storage.

On the flexibility of metal-organic frameworks.

Occasional, large amplitude flexibility in metal-organic frameworks (MOFs) is one of the most intriguing recent discoveries in chemistry and material science. Yet, there is at present no theoretical framework that permits the identification of flexible structures in the rapidly expanding universe of MOFs. Here, we propose a simple method to predict whether a MOF is flexible, based on treating it as a system of rigid elements, connected by hinges. This proposition is correct in application to MOFs based on rigid carboxylate linkers. We validate the method by correctly classifying known experimental MOFs into rigid and flexible groups. Applied to hypothetical MOFs, the method reveals an abundance of flexibility phenomena, and this seems to be at odds with the proportion of flexible structures among experimentally known MOFs. We speculate that the flexibility of a MOF may constitute an intrinsic impediment on its experimental realization. This highlights the importance of systematic prediction of large amplitude flexibility regimes in MOFs.

Unravelling the mechanism of the asymmetric hydrogenation of acetophenone by [RuX2(diphosphine)(1,2-diamine)] catalysts.

The mechanism of catalytic hydrogenation of acetophenone by the chiral complex trans-[RuCl2{(S)-binap}{(S,S)-dpen}] and KO-t-C4H9 in propan-2-ol is revised on the basis of DFT computations carried out in dielectric continuum and the most recent experimental observations. The results of these collective studies suggest that neither a six-membered pericyclic transition state nor any multibond concerted transition states are involved. Instead, a hydride moiety is transferred in an outer-sphere manner to afford an ion-pair, and the corresponding transition state is both enantio- and rate-determining. Heterolytic dihydrogen cleavage proceeds neither by a (two-bond) concerted, four-membered transition state, nor by a (three-bond) concerted, six-membered transition state mediated by a solvent molecule. Instead, cleavage of the H-H bond is achieved via deprotonation of the η(2)-H2 ligand within a cationic Ru complex by the chiral conjugate base of (R)-1-phenylethanol. Thus, protonation of the generated (R)-1-phenylethoxide anion originates from the η(2)-H2 ligand of the cationic Ru complex and not from NH protons of a neutral Ru trans-dihydride complex, as initially suggested within the framework of a metal-ligand bifunctional mechanism. Detailed computational analysis reveals that the 16e(-) Ru amido complex [RuH{(S)-binap}{(S,S)-HN(CHPh)2NH2}] and the 18e(-) Ru alkoxo complex trans-[RuH{OCH(CH3)(R)}{(S)-binap}{(S,S)-dpen}] (R = CH3 or C6H5) are not intermediates within the catalytic cycle, but rather are off-loop species. The accelerative effect of KO-t-C4H9 is explained by the reversible formation of the potassium amidato complexes trans-[RuH2{(S)-binap}{(S,S)-N(K)H(CHPh)2NH2}] or trans-[RuH2{(S)-binap}{(S,S)-N(K)H(CHPh)2NH(K)}]. The three-dimensional (3D) cavity observed within these molecules results in a chiral pocket stabilized via several different noncovalent interactions, including neutral and ionic hydrogen bonding, cation-π interactions, and π-π stacking interactions. Cooperatively, these interactions modify the catalyst structure, in turn lowering the relative activation barrier of hydride transfer by ~1-2 kcal mol(-1) and the following H-H bond cleavage by ~10 kcal mol(-1), respectively. A combined computational study and analysis of recent experimental data of the reaction pool results in new mechanistic insight into the catalytic cycle for hydrogenation of acetophenone by Noyori's catalyst, in the presence or absence of KO-t-C4H9.

Investigation of thorium salts as candidate materials for direct observation of the (229m)Th nuclear transition.

Recent efforts to measure the (229m)Th → (229g)Th nuclear transition sparked interest in understanding the electronic structure of wide-gap thorium salts. Such materials could be used to measure this nuclear transition using optical spectroscopy in solid-state devices. Here, we present screened hybrid density functional theory and many-body G0W0 calculations of two candidate materials, namely, Na2ThF6 and ThF4, for such a measurement. Our results show an electronic gap larger than 10 eV for both materials, suggesting that the internal conversion nuclear de-excitation channel would be suppressed in these materials. We also present results for ThX4 (X = Cl, Br, I), materials with smaller gaps significantly easier to access experimentally.

Optimizing nanoporous materials for gas storage.

In this work, we address the question of which thermodynamic factors determine the deliverable capacity of methane in nanoporous materials. The deliverable capacity is one of the key factors that determines the performance of a material for methane storage in automotive fuel tanks. To obtain insights into how the molecular characteristics of a material are related to the deliverable capacity, we developed several statistical thermodynamic models. The predictions of these models are compared with the classical thermodynamics approach of Bhatia and Myers [Bhatia and Myers, Langmuir, 2005, 22, 1688] and with the results of molecular simulations in which we screen the International Zeolite Association (IZA) structure database and a hypothetical zeolite database of over 100,000 structures. Both the simulations and our models do not support the rule of thumb that, for methane storage, one should aim for an optimal heat of adsorption of 18.8 kJ mol(-1). Instead, our models show that one can identify an optimal heat of adsorption, but that this optimal heat of adsorption depends on the structure of the material and can range from 8 to 23 kJ mol(-1). The different models we have developed are aimed to determine how this optimal heat of adsorption is related to the molecular structure of the material.

Carbon K-edge X-ray absorption spectroscopy and time-dependent density functional theory examination of metal-carbon bonding in metallocene dichlorides.

Metal-carbon covalence in (C5H5)2MCl2 (M = Ti, Zr, Hf) has been evaluated using carbon K-edge X-ray absorption spectroscopy (XAS) as well as ground-state and time-dependent hybrid density functional theory (DFT and TDDFT). Differences in orbital mixing were determined experimentally using transmission XAS of thin crystalline material with a scanning transmission X-ray microscope (STXM). Moving down the periodic table (Ti to Hf) has a marked effect on the experimental transition intensities associated with the low-lying antibonding 1a1* and 1b2* orbitals. The peak intensities, which are directly related to the M-(C5H5) orbital mixing coefficients, increase from 0.08(1) and 0.26(3) for (C5H5)2TiCl2 to 0.31(3) and 0.75(8) for (C5H5)2ZrCl2, and finally to 0.54(5) and 0.83(8) for (C5H5)2HfCl2. The experimental trend toward increased peak intensity for transitions associated with 1a1* and 1b2* orbitals agrees with the calculated TDDFT oscillator strengths [0.10 and 0.21, (C5H5)2TiCl2; 0.21 and 0.73, (C5H5)2ZrCl2; 0.35 and 0.69, (C5H5)2HfCl2] and with the amount of C 2p character obtained from the Mulliken populations for the antibonding 1a1* and 1b2* orbitals [8.2 and 23.4%, (C5H5)2TiCl2; 15.3 and 39.7%, (C5H5)2ZrCl2; 20.1 and 50.9%, (C5H5)2HfCl2]. The excellent agreement between experiment, theory, and recent Cl K-edge XAS and DFT measurements shows that C 2p orbital mixing is enhanced for the diffuse Hf (5d) and Zr (4d) atomic orbitals in relation to the more localized Ti (3d) orbitals. These results provide insight into how changes in M-Cl orbital mixing within the metallocene wedge are correlated with periodic trends in covalent bonding between the metal and the cyclopentadienide ancillary ligands.

Tetrahalide complexes of the [U(NR)2]2+ ion: synthesis, theory, and chlorine K-edge X-ray absorption spectroscopy.

Synthetic routes to salts containing uranium bis-imido tetrahalide anions [U(NR)(2)X(4)](2-) (X = Cl(-), Br(-)) and non-coordinating NEt(4)(+) and PPh(4)(+) countercations are reported. In general, these compounds can be prepared from U(NR)(2)I(2)(THF)(x) (x = 2 and R = (t)Bu, Ph; x = 3 and R = Me) upon addition of excess halide. In addition to providing stable coordination complexes with Cl(-), the [U(NMe)(2)](2+) cation also reacts with Br(-) to form stable [NEt(4)](2)[U(NMe)(2)Br(4)] complexes. These materials were used as a platform to compare electronic structure and bonding in [U(NR)(2)](2+) with [UO(2)](2+). Specifically, Cl K-edge X-ray absorption spectroscopy (XAS) and both ground-state and time-dependent hybrid density functional theory (DFT and TDDFT) were used to probe U-Cl bonding interactions in [PPh(4)](2)[U(N(t)Bu)(2)Cl(4)] and [PPh(4)](2)[UO(2)Cl(4)]. The DFT and XAS results show the total amount of Cl 3p character mixed with the U 5f orbitals was roughly 7-10% per U-Cl bond for both compounds, which shows that moving from oxo to imido has little effect on orbital mixing between the U 5f and equatorial Cl 3p orbitals. The results are presented in the context of recent Cl K-edge XAS and DFT studies on other hexavalent uranium chloride systems with fewer oxo or imido ligands.

Covalency in metal-oxygen multiple bonds evaluated using oxygen K-edge spectroscopy and electronic structure theory.

Advancing theories of how metal-oxygen bonding influences metal oxo properties can expose new avenues for innovation in materials science, catalysis, and biochemistry. Historically, spectroscopic analyses of the transition metal MO(4)(x-) anions have formed the basis for new M-O bonding theories. Herein, relative changes in M-O orbital mixing in MO(4)(2-) (M = Cr, Mo, W) and MO(4)(-) (M = Mn, Tc, Re) are evaluated for the first time by nonresonant inelastic X-ray scattering, X-ray absorption spectroscopy using fluorescence and transmission (via a scanning transmission X-ray microscope), and time-dependent density functional theory. The results suggest that moving from Group 6 to Group 7 or down the triads increases M-O e* (π*) mixing; for example, it more than doubles in ReO(4)(-) relative to CrO(4)(2-). Mixing in the t(2)* orbitals (σ* + π*) remains relatively constant within the same Group, but increases on moving from Group 6 to Group 7. These unexpected changes in orbital energy and composition for formally isoelectronic tetraoxometalates are evaluated in terms of periodic trends in d orbital energy and radial extension.

In silico screening of carbon-capture materials.

One of the main bottlenecks to deploying large-scale carbon dioxide capture and storage (CCS) in power plants is the energy required to separate the CO(2) from flue gas. For example, near-term CCS technology applied to coal-fired power plants is projected to reduce the net output of the plant by some 30% and to increase the cost of electricity by 60-80%. Developing capture materials and processes that reduce the parasitic energy imposed by CCS is therefore an important area of research. We have developed a computational approach to rank adsorbents for their performance in CCS. Using this analysis, we have screened hundreds of thousands of zeolite and zeolitic imidazolate framework structures and identified many different structures that have the potential to reduce the parasitic energy of CCS by 30-40% compared with near-term technologies.

Methane storage capabilities of diamond analogues.

Methane can be an alternative fuel for vehicular usage provided that new porous materials are developed for its efficient adsorption-based storage. Herein, we search for materials for this application within the family of diamond analogues. We used density functional theory to investigate structures in which tetrahedral C atoms of diamond are separated by -CC- or -BN- groups, as well as ones involving substitution of tetrahedral C atoms with Si and Ge atoms. The adsorptive and diffusive properties of methane are studied using classical molecular simulations. Our results suggest that the all-carbon structure has the highest volumetric methane uptake of 280 VSTP/V at p = 35 bar and T = 298 K. However, it suffers from limited methane diffusion. Alternatively, the considered Si and Ge-containing analogies have fast diffusive properties but their adsorption is lower, ca. 172-179 VSTP/V, at the same conditions.

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 HS(2)P(o-CF(3)C(6)H(4))(2) 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(4)][S(2)PR(2)] complexes, where R = Me (1), Ph (2), p-CF(3)C(6)H(4) (3), m-CF(3)C(6)H(4) (4), o-CF(3)C(6)H(4) (5), o-MeC(6)H(4) (6), and o-MeOC(6)H(4) (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 S(2)P(o-CF(3)C(6)H(4))(2)(-) (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(3), 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 C(2v) in 2-4 to C(2) in 5-7. As a consequence, the change in aryl group orientation appears to make the ortho-substituted S(2)PR(2)(-) anions "softer" extractants compared with analogous Ph-, p-CF(3)C(6)H(4)-, and m-CF(3)C(6)H(4)-containing ligands (2-4) by raising the energies of the sulfur valence orbitals and enhancing orbital mixing between the S(2)P 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 S(2)P(o-CF(3)C(6)H(4))(2)(-) anion in 5. These results correlate with the special extraction properties associated with HS(2)P(o-CF(3)C(6)H(4))(2), and suggest that ligand K-edge XAS and TDDFT can be used to guide separation efforts relevant to advanced fuel cycle development.