PPSe Se

cis-dppESe7

PPS S

cis-dppES6

PPO O

cis-dppEO5

The Change in Extraction Efficiency of f-block elements with the Variation of Electron Donor Atoms in Bidentate Ligands Jeremy Cunningham, Brian Rawls, Paul T. Morse and Shannon M. Biros*

Grand Valley State University, Department of Chemistry, Allendale, MI 49401

Figure 1: Tributyl Phosphate structure, used in PUREX, and General CMPO structure, used in TRUEX.

Synthesis of the cis-dppE Class Ligands

Table 2: All gathered extraction efficiency data to date. Ongoing research will generate more inter-ligand comparative data.

Figure 6: Arsenazo III-Metal Complex

Future Plans:Our lab’s future work lies in compiling data for extraction efficiencies of all heavy metals with all of our current ligands. Further attempts at X-ray crystallography structures are ongoing. We strive to determine the impacts of atomic radius, f-orbital shape, type of chelating group, distance between chelating groups, and other factors on complex properties and extraction efficiencies.

Figure 8: Shown above are two proposed future ligands for analysis. On the left is a proposed linear metal polymer in which the bridge

between the β-phosphoryl groups is undetermined. The structure on the right shows a benzene ring replacing the bridge carbons, which

may prove able to donate electron density to the complex.

Figure 2: Bidentate Phosphoryl Ligands synthesized for initial study.

Structure Characterization:Attempts at growing cis-dppE crystals in various solvent systems have allowed for the determination of exact spacial orientation and physical structure of the cis-dppE-metal complexes by way of X-Ray crystallography.

Tributyl Phosphate1

P OO

OO

PR

R

O O

NR

R

General CMPO2

Figure 3: Synthesis of cis-dppESe.

Acknowledgements:As part of the Grand Valley State University Chemistry Research Program, we would like to thank all of the staff of the GVSU Chemistry Department, especially Professor Jim Krikke and Professor Randy Winchester, along with our student research partners, Ben Nicholson, Brian Rawls, and Jeremy Cunningham. Additionally, we would like to thank Professor Eric Werner (University of Tampa), Dr. Richard Staples (Michigan State Univeristy), and Dr. Tom Guarr (Michigan State University Bioeconomy Institute). We also thank the GVSU chemistry department, GVSU NSF ADVANCE, GVSU OURS, the Weldon Fund, NSF-REU, and the IUCr crystallographic travel fund from Crystallographic Resources, Inc. for providing financial support. Finally, we would like to thank the kittens for their emotional support.

References:[1]Gorden, A., DeVore, M., Maynard, B., Inorg. Chem., 2013, 52, 3445-3458. [2] Peters, M.W., Scott, M.J., Werner, E.J., Inorg. Chem. 2002, 41, 1707-1716. [3]Werner, E.; Datta, A.; Jocher, C.; Raymond, K. Angew. Chem. Int. Ed. 2008, 47, 8568-8580. [4]Barnes, C.L., Duval, P.B., Kannan, S., Moody, M.A., Inorg. Chem., 2006, 45, 9206-9212. [5]F. Arnaud-Neu, V.Bohmer, J.F. Dozol, C. Gruttner, R.A. Jakobi, D.Kraft, O. Mauprivez, H. Rouquette, M.J. Schwing-Weill, N. Simon and W. Vogt. J. Chem Soc., Perkin Trans. 2, 1996, 1175. [6]Katajisto, J.; Karskela, T.; Heinonen, P.; Lonnberg, H. J. Org. Chem. 2002, 67, 7995-8001. [7]Frank, A. W.; Daigle, D. J. Phosphorus and Sulfur 1981, 10, 225-260. [8]Ermakova, N.V, Ivanov, V.M., J. Anal. Chem., 2001, 56, 519-523. [9]Martin, V., Lex, L., Keana, J. OPPI Briefs, 1995, 27, 117-120. [10]Schuster, E. M.; Nisnevich,g.; Botoshanksy, M; Gandleman, M. Organometallics. 2009. 28, 5025-5031. [11]Henicke, J.; Peulecke, N.; Jones, P. G. Chem. Commun. 2005, 262-264.

Ongoing Work:Extraction efficiency studies are currently being preformed on the ligands

using liquid-liquid extraction and UV-Vis spectroscopy. The ligand, in an organic solvent, and aqueous metal solution are mixed and allowed to equilibrate. Extraction efficiency is measured by mixing the remaining aqueous metal solution with the optically active compound, Arsenazo III. By measuring the absorption of the solution at 655 nm (Ln) or 665 nm (An) before and after extraction, a percent extraction efficiency is recorded.

Abstract:Experts predict that the maximum possible oil production will occur in the next 5-25 years1 using current methods and, consequently, the need for alternative sources of energy is growing. For most of Europe, nuclear power is the dominant source of electricity, whereas the United States gets 83% of its energy by way of fossil fuels while only 8% comes from nuclear power2. In addition to wind and solar, nuclear energy is an attractive alternative, with the ability to generate significant amounts of energy with low atmospheric emissions. However, critical issues surrounding the use of nuclear power include: Long-term nuclear waste storage and waste remediation. Due to environmental and economic concerns, a recent resurgence in the chemistry of actinides has been inspired to develop new separation technologies.

Background:

Figure 4: Crystal structure obtained from cis-dppESe. One Selenium atom (shown in yellow) is projecting out of the plane while the other Se is directed into the plane. The sp3 hybridized phosphorus has a tetrahedral geometry.

Figure 5: Crystal structure obtained from cis-dppEO-thorium complex. Two cis-dppEO ligands surround the Th4+ center. The alkene segment of the third cis-dppEO has been converted to an epoxide. This is likely (a) an impurity from the ligand preparation, or (b) a reaction between the ligand and the Th(IV) center, as it has been shown that Th(IV) can catalyze conversion of alkenes to epoxides. Two nitrate groups reliably participate in the primary coordination sphere while two other nitrate groups exist in a disordered state in the secondary coordination sphere (not shown).

The goal of nuclear waste remediation is to reuse the products produced from the nuclear fission process. Much of the waste generated is composed of unspent, energy-rich, fissile elements called high level waste (HLW) that can be reused for fission reactions in next generation fission reactor. The remediation of HLW has been achieve through the PUREX (Plutonium-URanium EXtraction) process which utilizes an organic ligand called tri-butyl phosphate.

While the PUREX, and similar processes, present major advances in the overall reduction of HLW generated, there are still products generated from fission called intermediate level waste (ILW) and low level waste (LLW). The goal of nuclear waste remediation is to eliminate all levels of waste generated, making nuclear energy an attractive, zero carbon, energy source.

The goal of the Biros research group at GVSU is to analyze a class of organic molecules known to have high binding affinity toward the specific metals in intermediate and low level waste. The molecules under observation are derivatives of a class of compounds used in the TRUEX (TRans Uranium EXtraction) process. These remediation compounds are called CMPO (carbamoylmethylphosphine oxide) ligands, and are known to have a high degree of binding affinity toward a range of metal cations. The Biros lab is observing how the variation of the election donating atoms on the ligand effects the extraction efficiency of f-block metals.

Starting Material Reactant Reaction Conditions

Product

Cis-dppE H2O2 THFReflux, 4hrs

Cis-dppEO

Cis-dppE S8 THF25°C

3 Hours

Cis-dppES

Cis-dppE 2 Se Toluene25°C

4 Hours

Cis-dppESe

+ 2 Se(s)

ElementMetal Extraction

Percentage for cdppeO

Metal Extraction Percentage for

cdppeS

Metal Extraction Percentage for

cdppeSe

Uranium UO2(NO3)2

91% 92% 99%

 ThoriumTh(NO3)4

83% 97%

YtterbiumYb(NO3)3 

10% 13%

 DysprosiumDy(NO3)3 

10% 5.0%

 EuropiumEu(NO3)3 

21% 5.9%

LanthanumLa(NO3)3 

9.5% 18% 7%