A5032434259- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Radioactive element chemistry and processing
- Lanthanide and Transition Metal Complexes
- Radiopharmaceutical Chemistry and Applications
- Nuclear Materials and Properties
- Chemical Synthesis and Characterization
- Medical Imaging Techniques and Applications
- Nuclear materials and radiation effects
- Crystallography and molecular interactions
- Medical Imaging and Pathology Studies
- Thermal and Kinetic Analysis
- Analytical chemistry methods development
- Nuclear reactor physics and engineering
- Nitric Oxide and Endothelin Effects
- Graphite, nuclear technology, radiation studies
- Advanced Power Generation Technologies
- Inorganic Chemistry and Materials
- Metal-Catalyzed Oxygenation Mechanisms
- Molten salt chemistry and electrochemical processes
- Radioactive contamination and transfer
- Organometallic Complex Synthesis and Catalysis
- Radioactive Decay and Measurement Techniques
- Vanadium and Halogenation Chemistry
- Phosphorus and nutrient management
Lawrence Livermore National Laboratory
2019-2024
Los Alamos National Laboratory
2014-2021
University of Washington
2019-2020
Los Alamos Medical Center
2017-2018
University of Nevada, Las Vegas
2012-2014
University of Nevada, Reno
2012
Abstract Actinium-225 is a promising isotope for targeted-α therapy. Unfortunately, progress in developing chelators medicinal applications has been hindered by limited understanding of actinium chemistry. This knowledge gap primarily associated with handling actinium, as it highly radioactive and short supply. Hence, Ac III reactivity often inferred from the lanthanides minor actinides (that is, Am, Cm), success. Here we overcome these challenges characterize HCl solutions using X-ray...
Characterizing how actinide properties change across the f-element series is critical for improving predictive capabilities and solving many nuclear problems facing our society. Unfortunately, it difficult to make direct comparisons 5f-element because so little known about trans-plutonium elements. Results described herein help address this issue through isolation of An(S2CNEt2)3(N2C12H8) (Am, Cm, Cf). These findings included first single crystal X-ray diffraction measurements Cm-S (mean...
Metal aquo ions occupy central roles in all equilibria that define metal complexation natural environments. These complexes are used to establish thermodynamic metrics (i.e., stability constants) for predicting binding, which essential defining critical parameters associated with aqueous speciation, chelation, vivo transport, and so on. As such, establishing the fundamental chemistry of actinium(III) ion (Ac-aquo ion, Ac(H2O)x3+) is current efforts develop 225Ac [t1/2 = 10.0(1) d] as a...
A major chemical challenge facing implementation of 225Ac in targeted alpha therapy—an emerging technology that has potential for treatment disease—is identifying an chelator is compatible with vivo applications. It unclear how to tailor a Ac binding because coordination chemistry poorly defined. Most inferred from radiochemical experiments carried out on microscopic scales. Of the few compounds have been characterized spectroscopically, success only reported simple inorganic ligands. Toward...
Arylazide and diazene activation by highly reduced uranium(IV) complexes bearing trianionic redox-active pyridine(diimine) ligands, [CpPU(MesPDIMe)]2 (1-CpP), Cp*U(MesPDIMe)(THF) (1-Cp*) (CpP = 1-(7,7-dimethylbenzyl)cyclopentadienide; Cp* η5-1,2,3,4,5-pentamethylcyclopentadienide), Cp*U(tBu-MesPDIMe) (THF) (1-tBu) (2,6-((Mes)N═CMe)2-p-R-C5H2N, Mes 2,4,6-trimethylphenyl; R H, MesPDIMe; C(CH3)3, tBu-MesPDIMe), has been investigated. While 1-Cp* 1-CpP readily reduce N3R (R Ph, p-tolyl) to form...
Inspired by the multielectron redox chemistry achieved using conventional organic-based redox-active ligands, we have characterized a series of iron-functionalized polyoxovanadate–alkoxide clusters in which metal oxide scaffold functions as three-dimensional, electron-deficient metalloligand. Four heterometallic were prepared through sequential reduction, demonstrating that is capable storing up to four electrons. These reduced products cyclic voltammetry, IR, electronic absorption, and 1H...
Ln<sup>II</sup>(C<sub>5</sub>H<sub>4</sub>SiMe<sub>3</sub>)<sup>1−</sup>have been characterized by XANES and DFT.
Cm<sup>III,</sup>Am<sup>III</sup>, and Ac<sup>III</sup>have been characterized by solution L<sub>3</sub>-edge X-ray absorption spectroscopy as a function of nitric acid concentration. This enabled the first experimental determination Cm Ac nitrate distances.
Abstract The use of α-emitting radionuclides in targeted alpha therapy (TAT) holds great potential for treatment human diseases, such as cancer, due to the short pathlength and high potency α particle, which can localize damage cells while minimizing effects healthy surrounding tissues. In this review several having emission properties applicable TAT are discussed from a radiochemical point view. Overviews production, separation chelation aspects relative developing radiopharmaceuticals...
Abstract Advancing our understanding of the minor actinides (Am, Cm) versus lanthanides is key for developing advanced nuclear‐fuel cycles. Herein, we describe preparation (NBu 4 )Am[S 2 P( t Bu C 12 H 6 )] and two isomorphous lanthanide complexes, namely one with a similar ionic radius (i.e., Nd III ) an isoelectronic (Eu ). The results include first measurement Am−S bond length, mean value 2.921(9) Å, by single‐crystal X‐ray diffraction. Comparison Eu complexes revealed subtle electronic...
Abstract Nitrosobenzene (PhNO) serves as a stable analogue of nitroxyl (HNO), biologically relevant, redox‐active nitric oxide derivative. Capture nitrosobenzene at the electron‐deficient β‐diketiminato nickel(I) complex [ i Pr 2 NN F6 ]Ni results in reduction PhNO ligand to ./− species coordinated square planar Ni II center ]Ni(η ‐ONPh). Ligand centered leads 2− moiety bound supported by XAS studies. Systematic investigation structure–reactivity patterns and ligands reveals parallels with...
Thenoyltrifluoroacetone (HTTA)-based extractions represent popular methods for separating microscopic amounts of transuranic actinides (i.e., Np and Pu) from macroscopic actinide matrixes (e.g. bulk uranium). It is well-established that this procedure enables +4 to be selectively removed +3, + 5, +6 f-elements. However, even highly skilled well-trained researchers find process complicated (at times) unpredictable. difficult improve the HTTA extraction-or alternatives-because little...
One of the main challenges in targeted alpha therapy is assuring delivery α‐particle dose to cells. Thus, it critical identify ligands for α‐emitting radiometals that will form complexes are very stable, both vitro and vivo. In this investigation, thorium‐227 ( t 1/2 = 18.70 days) chelation containing hydroxypyridinonate (HOPO) or picolinic acid (pa) moieties stability resultant were studied. Chelation reactions followed by reversed‐phased HPLC gamma spectroscopy. Studies revealed high 227...
Hydrogel infused additive manufacturing (HIAM) is an emerging technique for the of ceramics and metals. Distinct from slurry- or powder-based techniques, a hydrogel scaffold obtained in the...
The reaction of Ce(III) or Pu(III) with 1,10-phenanthroline-2,9-dicarboxylic acid (PDAH2) results in the formation new f-element coordination complexes. In case cerium, Ce(PDA)(H2O)2Cl·H2O (1) [Ce(PDAH)(PDA)]2[Ce(PDAH)(PDA)] (2) was isolated depending on Ce/ligand ratio reaction. structure 2 is composed two distinct substructures that are constructed from same monomer. This monomer a cation bound by one PDA(2-) dianionic ligand and PDAH(-) monoanionic ligand, both which tetradentate....
Increasing access to the short-lived α-emitting radionuclide astatine-211 (211At) has potential advance targeted α-therapeutic treatment of disease and solve challenges facing medical community. For example, there are numerous technical needs associated with advancing use 211At in α-therapy, e.g., improving chelates, developing more effective targeting, characterizing vivo behavior. There is an insufficient understanding astatine chemistry support these efforts. The one least developed all...
A series of uranium amides were synthesized from N,N,N-cyclohexyl(trimethylsilyl)lithium amide [Li][N(TMS)Cy] and tetrachloride to give U(NCySiMe3)x(Cl)4–x, where x = 2, 3, or 4. The diamide was isolated as a bimetallic, bridging lithium chloride adduct ((UCl2(NCyTMS)2)2-LiCl(THF)2), the tris(amide) monometallic species (UCl(NCyTMS)3-LiCl(THF)2). tetraamide complex four-coordinate pseudotetrahedron. Cyclic voltammetry revealed an easily accessible reversible oxidation wave, upon chemical...
Radionuclides find widespread use in medical technologies for treating and diagnosing disease. Among successful emerging radiotherapeutics, 119Sb has unique potential targeted therapeutic applications low-energy electron-emitting isotopes. Unfortunately, developing 119Sb-based drugs been slow comparison to other radionuclides, primarily due limited accessibility. Herein is a production method that overcomes this challenge expands the available time large-scale distribution use. Our approach...
Abstract Astatine-211 is an attractive radionuclide for use in targeted alpha therapy of blood-borne diseases and micrometastatic diseases. Efficient isolation methods that can be adapted to robust automated 211 At systems are high interest improving the availability At. Based on early studies Bochvarova co-workers involving from irradiated thorium targets, we developed a method bismuth targets using tellurium-packed columns. Dissolution accomplished HNO 3 ; however, not captured Te column...
Abstract Advancing our understanding of the minor actinides (Am, Cm) versus lanthanides is key for developing advanced nuclear‐fuel cycles. Herein, we describe preparation (NBu 4 )Am[S 2 P( t Bu C 12 H 6 )] and two isomorphous lanthanide complexes, namely one with a similar ionic radius (i.e., Nd III ) an isoelectronic (Eu ). The results include first measurement Am−S bond length, mean value 2.921(9) Å, by single‐crystal X‐ray diffraction. Comparison Eu complexes revealed subtle electronic...
An investigation of the structural, thermodynamic, and electronic transport properties isoelectronic chemical substitution series $\mathrm{Ce}{({\mathrm{Pd}}_{1\ensuremath{-}x}{\mathrm{Ni}}_{x})}_{2}{\mathrm{P}}_{2}$ is reported, where a possible ferromagnetic quantum critical point uncovered in temperature-concentration ($T\text{\ensuremath{-}}x$) phase diagram. This behavior results from simultaneous contraction unit cell volume, which tunes relative strengths Kondo...
Uranium complexes (MesDAE)2U(THF) (1-DAE) and Cp2U(MesDAE) (2-DAE) (MesDAE = [ArN-CH2CH2-NAr]; Ar 2,4,6-trimethylphenyl (Mes)), bearing redox-innocent diamide ligands, have been synthesized characterized for a full comparison with previously published, redox-active diimine complexes, (MesDABMe)2U(THF) (1-DAB) Cp2U(MesDABMe) (2-DAB) (MesDABMe [ArN═C(Me)C(Me)═NAr]; Mes). These analogues maintain an analogous steric environment to their ligand counterparts facilitate study aimed at determining...