This presentation addresses nuclear waste remediation processes and covers my research conducted under Dr. S. Biros (GVSU)

1. Synthesis and Characterization of
Bidentate Phosphoryl Ligands for
the Chelation of f-block Metals
Jeremy Cunningham

2. Power
Crisis
• Nuclear Power Plant:
$2-6 Billion
• One Fuel Cycle: $40mil
• Coal: $0.3/kWh
• Oil: $0.2/kWh
• Nuclear: $0.08/kWh
• Main Reason: Nuclear
Weapons
Images from: YaleClimateCommunications.org

3. Nuclear
Power
•Provides 20% of energy in
USA
•104 reactors in 31 states
•Cost of energy from
nuclear is cheaper and
more stable than from
petroleum
•Nuclear power plants
reduce the amount of
greenhouse gases
produced
Images from: http://www.world-nuclear.org

4. Nuclear Waste Storage
• Nuclear waste is
projected to increase
30% over the next
twenty years
• Some waste products
will generate
considerable heat as
they decay, others will
remain intensely
radioactive for very long
time periods
• 270,000 metric tons of
high level radioactive
waste has accumulated
in 30 countries

5. Nuclear Waste: What is it?
The Royal Society Science Policy Centre Report 10/11, Oct 2011; ISBN 978-0-85403-891-6.
**it is this 1% of actinides
that accounts for the
long term radioactivity of
the waste (103-106
years)**
lanthanides in this mixture
interfere with transmutation of
highly radioactive actinides

6. Other Uses for Lanthanides and
Actinides
 MRI Contrast Agents:
 Nd:YAG Lasers
 Batteries
 Magnets

7. Metal Chelation: Defining Terms
• A complex is formed when a
metal atom or ion, acting as a
Lewis acid, bonds by
accepting lone-pair electrons
from ligands, acting as Lewis
bases.
• A monodentate ligand
attaches at a single
coordination site of the central
metal, a bidentate ligand at
two sites, and a polydentate
ligand at two or more sites.
• Coordination number
represents the total number of
points of attachment for a
given metal atom or ion.
http://chemwiki.ucdavis.edu/Inorganic_Chemistry/Coordination_Chemistry

8. Metal Chelation: HSAB Theory
 Hard Acids:
 High Charge
 Small Atomic Radius
 Ex.) Ti4+, Cr3+, Cr6+
 Soft Acids:
 large atomic/ionic radius
 Low Oxidation States
 Ex.) Pt2+, Pd2+, Ag+, Au+,
Hg2+
http://www.chem.latech.edu
Pearson, Ralph G. J. Chem. Sci., Vol. 117, No. 5, 2005, pp. 369–377
 Hard Bases:
 High electronegativity
 Low Polarizability
 Ex.) OH–, F–, Cl–,
CH3COO–, CO3
2–
 Soft Bases:
 Lower Electronegativity
 High Polarizability
 Ex.) R3P, SCN–, I–, CN–

9. Chelation with d-block Metals
• The transition elements
are those which have
open d-subshells
• Geometry is metal
dependent
• Easier to Separate
faculty.uml.edu/ndeluca/84.334/topics/topic6.html

10. Metal Chelation: HSAB Theory
 Hard Acids
 Ti4+, Cr3+, Cr6+
 Soft Acids
 Pt2+, Pd2+, Ag+, Au+, Hg2+
 Hard Bases
 OH–, F–, Cl–, NH3, CH3COO–,
CO3
2–
 Soft Bases
 R3P, SCN–, I–, CN–

11. Chelation of the Lanthanides
 Lanthanides:
• bonding is more ionic (buried 4f-
orbitals)
• common oxidation state is 3+ across
the row
• ionic radii varies only 17 picometers
from La3+ (103 pm) to Lu3+ (86 pm)

12. Chelation of the Actinides
 Actinides:
• bonding is more covalent (5f
orbital participation)
• Charges vary, ions and can have
oxides
• U6+ Th4+ Pu4+ Am3+ Np5+
UO2
2+ PuO2
2+
• ionic radii similar as well (Th4+ =
105 pm; Np5+ = 101 pm; Tb3+ =
104 pm)

13. Separation of f-block metals
 Actinides:
• bonding is more covalent (5f orbital
participation)
• Slightly larger than lanthanides with similar
oxidation number
 Lanthanides:
• bonding is more Ionic
(buried 4f orbitals)
 f-element coordination chemistry:
• Both are considered as hard acids,
ligand interaction predominately
determined by steric/electrostatic
interactions.

14. Nuclear waste remediation
Kaminski, M. D.; Mertz, C. J.; et. al, J. Am. Chem. Soc. 2009, 131, 15705

15. The PUREX
Process
• Herbert H. Anderson
and Larned B. Asprey
at the University of
Chicago, as part of the
Manhattan Project
Kaminski, M. D.; Mertz, C. J.; et. al, J. Am. Chem. Soc. 2009, 131, 15705

16. The TRUEX
Process
• Developed in the
1980’s for the
extraction of all minor
actinides and
lanthanides.
Kaminski, M. D.; Mertz, C. J.; et. al, J. Am. Chem. Soc. 2009, 131, 15705

17. The
DIAMEX
Process
• Predecessor to the
TRUEX Process
• More eco-friendly upon
incineration
Kaminski, M. D.; Mertz, C. J.; et. al, J. Am. Chem. Soc. 2009, 131, 15705

18. The
SANEX
Process
• Sulfur-based soft-donor
extractants show
selectivity towards
An(III)
• Varying pH enhances
selectivity and alters
solubility properties
Kaminski, M. D.; Mertz, C. J.; et. al, J. Am. Chem. Soc. 2009, 131, 15705

19. Nuclear waste remediation
D. Häussinger, J. Huang, S. Grzesiek Journal of the American Chemical Society 2009 131 (41), 14761-14767
 Actinides
 Tend to coordinate best with
soft donor atoms (S/N)
 Lanthanides
 Tend to coordinate best with
hard donor atoms.

20. The Biros Research Group
La3+
HN
N
O
P
OEtO
EtO
NH
O
P
O OEt
OEtHN
O
P
O
EtO OEt
3 NO3
-

21. Previous Work
Cis-1,2-bis(diphenylphosphino)
Ethylene Dioxide
(Cis-dppeO2)
 Coordinates to all f-block
metals
 No cis-trans isomerization
observed
Cis-1,2-bis(diphenylphosphino)
Ethylene Disulfide
(Cis-dppeS2)
 Coordinates relatively poorly
to Lanthanides
 Cis-trans isomerization
P.T. Morse et al., Polyhedron (2015), http://dx.doi.org/10.1016/j.poly.2015.05.016
Paul Morse Brian Rawls

22. Our Approach
 Conjugated, rigid bridge ligand
 Large Atomic Radius; greater electron dispersion, softer
ligand
 Longer bond length with a stronger dipole moment
P.T. Morse et al., Polyhedron (2015), http://dx.doi.org/10.1016/j.poly.2015.05.016

23. Goals
 Synthesize the
selenide derivative
of cis-dppe
 Form complexes
with f-block metals
 Study the
extraction
efficiency of cis-
dppeSe2
S
e
S
e
Previous Extraction Data

24. Characterization Methods:
Phosphorus-31 NMR
• 31P has an isotopic abundance of 100%
• The 31P nucleus also has a spin of ½,
making spectra relatively easy to interpret.

25. X-Ray Crystallography
•Bruker Diffractometer
•Olex2
•Atomic Resolution
Characterization Methods:
X-Ray Crystallography

26. X-Ray Crystallography
•Bruker Diffractometer
•Olex2
•Atomic Resolution
Characterization Methods:
X-Ray Crystallography

27. SUMMER 2014
 Trans-dppeSe2 observed
(δP=Se:29.6ppm)
• Reaction occurred at
reflux (65ºC) for 20 hours
• Red powder observed
upon work-up
+KSeCN
THF

28. Preparation of cis-1,2-
bis(diphenylphosphoryl)Ethylene Diselenide
• Concentrated reaction conditions
(0.13M)
• Under nitrogen
• Stirred at room temperature for 4
hours
+2Se(s)
Toluene

29. 31PNMR of reaction mixture
• Three visible
products.
• Oxidized
phosphorus:
δ=(+)ppm

30. Cis-1,2-bis(diphenylphosphoryl)Ethylene
Monoselenide
δP:= -27.5ppm(d)
3JP-P= 22.5Hz
δP=Se=+22.2ppm(d)
1JSe-P= 1258Hz

31. Trans-1,2-bis(diphenylphosphoryl)Ethylene
Diselenide
δP=Se=+29.6ppm(s)
1JSe-P=695Hz, 815Hz
Z. Phasha, S. Makhoba, A. Muller, Acta Crystallographica E 68 (2012)

32. Cis-1,2-bis(diphenylphosphoryl)Ethylene
Diselenide
• After Benzene
Recrystallization
δ: +23.7ppm(s)
1JP=Se= 737.1Hz
ppm

33. X-Ray Crystal Structure
P=O: 1.50Å
P=S: 1.95Å
P=Se: 2.10Å

34. Phosphorus-Chalcogenide Bond
Character
• Strong dipole, weak
bond strength
• Unobservable on IR
• P to Se σ bond
determines bond
energy
Bond
Dipole
Moment (D) IR(cm-1)
31PNMR
(ppm)
P=O 4.51* 1173 21.6
P=S 4.88* 637 32.3
P=Se 5.17* 561* 23.7
P.T.Morse Th(IV) complexes with cis-ethylenebis(diphenylphosphine oxide): X-ray structures and NMR solution studies Polyhedron
*Kenneth B. Capps,Bodo Wixmerten,Andreas Bauer, and, and Carl D. Hoff Inorganic Chemistry 1998 37, 2861-2864

35. Phosphorus-Chalcogenide Bond
Character
• Strong dipole, weak
bond strength
• Unobservable on IR
• P to Se σ bond
determines bond
energy
• Observed dissociation
of Selenium
Bond
Dipole
Moment (D) IR(cm-1)
31PNMR
(ppm)
P=O 4.51* 1173 21.6
P=S 4.88* 637 32.3
P=Se 5.17* 561* 23.7
P.T.Morse Th(IV) complexes with cis-ethylenebis(diphenylphosphine oxide): X-ray structures and NMR solution studies Polyhedron
*Kenneth B. Capps,Bodo Wixmerten,Andreas Bauer, and, and Carl D. Hoff Inorganic Chemistry 1998 37, 2861-2864

36. Cis-Trans Isomerization
• Observed as sole product in KSeCN reaction
• During attempted isolation via column
chromatography
• Under heated reaction conditions
• In very dilute solutions
• After extraction studies

37. Cis-Trans: Aguiar & Daigle (1964)
 Observations:
• Photoisomerization of cis-
dppe failed.
• Benzene minimized
isomerization
• Treatment trans-dppeS2
with acetic acid lead to
trans-dppeO2
• Reflux in THF with PCl3
caused isomerization
A.M. Aguiar and D. Daigle, J. Am. Chem. Soc., 86, 2299 (1964)
,

38. Cis-Trans Thermal Isomerization
A.M. Aguiar and D. Daigle, J. Am. Chem. Soc., 86, 2299 (1964)
Sigl, M., Schier, A. & Schmidbaur, H. Zeitschrift für Naturforschung B, 53(11), pp. 1301-1306 (2014).
 Requires a strong lewis
acid (such as PCl3)
MX3= AlBr3,
GaBr3, InBr3

39. Cis-Trans Thermal Isomerization
Sigl, M., Schier, A. & Schmidbaur, H. Zeitschrift für Naturforschung B, 53(11), pp. 1301-1306 (2014).
 Requires a strong lewis
acid (such as PCl3)
 Unoxidized phosphines.
MX3=GaBr3,
AlBr3, InBr3

40. Cis-Trans Photoisomerization
Janet B. Foley, Alice E. Bruce, and Mitchell R. M. Bruce Journal of the American Chemical Society 1995 117 (37), 9596-9597

41. Cis-Trans Photoisomerization
• π* character increases
with atom softness
• Isomerization occurred
within 3 mins by
exposure to >300nm
light
Janet B. Foley, Alice E. Bruce, and Mitchell R. M. Bruce Journal of the American Chemical Society 1995 117 (37), 9596-9597

42. Cis-Trans Isomerization
Hν
Δ

43. Cis-Trans Isomerization
Hν
Δ
δ- - - δ- - -δ- - δ- -δ- δ-
<< <
P=O: 1.50Å P=S: 1.95Å P=Se: 2.10Å

44. Extraction Procedure
• 1x10-4M An(III)/La(III)
solution in 1M HNO3
• 3x10-4M cis-dppeSe2
solution in DCM.
Martin, K. A.; Horwitz, E. P.; Ferraro, J. R. Solvent Extr. Ion Exch. 1986, 4, 449;
Stockmann, T.; Ding, Z. Analytical Chem. 2011, 83, 7542–7549.
Aqueous
1M HNO3
e-pure water
Organic
CH2Cl2
M3+
M3+
M3+
CMPO
M3+M3+
M3+
CMPO
CMPO
CMPO
shake for 24 hours
M3+
M3+
M3+
CMPO
M3+
M3+ M3+
CMPO
CMPO CMPO

45. Extraction Procedure
• 1x10-4M An(III)/La(III)
solution in 1M HNO3
• 3x10-4M cis-dppeSe2
solution in DCM.
o 6.4x10-4M Arsenazo
solution in Formic Acid
Buffer (pH=2.9)
o λmax=655nm for Ln(III)
λmax=665nm for An(III)
Martin, K. A.; Horwitz, E. P.; Ferraro, J. R. Solvent Extr. Ion Exch. 1986, 4, 449;
Stockmann, T.; Ding, Z. Analytical Chem. 2011, 83, 7542–7549.
Aqueous
1M HNO3
e-pure water
Organic
CH2Cl2
M3+
M3+
M3+
CMPO
M3+M3+
M3+
CMPO
CMPO
CMPO
shake for 24 hours
M3+
M3+
M3+
CMPO
M3+
M3+ M3+
CMPO
CMPO CMPO

46. Previous Extraction Efficiencies
 Cis-dppeO2
P.T.Morse Th(IV) complexes with cis-ethylenebis(diphenylphosphine oxide): X-ray structures and NMR solution studies Polyhedron

47. Previous Extraction Efficiencies
 Cis-dppeS2

48. Extraction Efficiency of cis-1,2-
bis(diphenylphosphino) Ethylene
Diselenide

49. Synthesis of cis-dppeSe1
• Reaction occurred in
benzene
• The mixture was
sonicated for 20mins
before sitting for 3hrs
• ½ Equivalent of
selenium, sit for 24 hours
• Methanol
recrystallization

50. Characterization of Cis-dppeSe1
 Crystal Structure
 31P-NMR
• δP=Se=+22.2ppm(d)
• 1JSe-P= 1258Hz
• δP:= -27.5ppm(d)
• 3JP-P= 22.5Hz

51. Summer 2015
Cis-dppeS2: Platinum Complex
2
2

52. Future Work
 Form more f-block metal complexes
 Preform more extraction studies
 Synthesize a new ligand

53. Acknowledgements and Funding
 Acknowledgements
 Dr. Shannon Biros
 Dr. John Bender
 Dr. Richard Staples
 GVSU Chemistry Faculty
• Funding
• National Science Foundation
• GVSU: OURS
Dr. Richard Staples
Michigan State University
Dr. John Bender
Grand Valley State University

54. Questions?