Elusive Actinium: A First Glimpse into the Coordination Chemistry of Element 89

Project Overview

Actinide elements play a central role in several application spaces that are critical to the nation, notably in the nuclear energy sector and defense industry for the past ~80 years and, more recently, in nuclear medicine. However, while the chemical properties of actinide elements such as uranium and plutonium are relatively well established, the chemistry of the other members of the actinide family (example: actinium, americium, curium…) is still poorly understood. The need to better understand the chemistry of these elements is particularly important due to the growing interest in actinide-based cancer treatments and the presence of actinide materials in a wide variety of nuclear waste streams (from nuclear power plants, fundamental research labs, military activities, etc.). The difficulty in studying these radioactive elements arises from the low availability of their research isotopes and incompatibility with most chemistry techniques and laboratory protocols. In this project, we opened a new front in the chemistry of actinide elements by studying their interactions with macromolecules. This innovative approach allowed us to harvest previously unknown chemical information on the elements actinium, americium, curium, and related elements, while complying with the very low availability of their research isotopes. The techniques developed in the frame of our project enable a better utilization of the nation's strategic stockpile of research isotopes. The developed strategy affords a unique look into the chemistry of the actinide elements and resulted in a better understanding of their interactions with environmental systems as well as novel actinide-containing materials.

Mission Impact

Our project resulted in one record of invention that is now part of a U.S. patent application. Some of the results obtained during this two-year project have already been published in multiple high-impact peer-reviewed journals and more research articles are in preparation. The obtained results enhance our fundamental understanding and provide applied science solutions for elements that are an integral part of past, present, and future nuclear materials. We developed science and technology tools and capabilities to meet future national security challenges in Lawrence Livermore National Laboratory's core competency of nuclear, chemical, and isotopic sciences. The results derived from this project are also being used to leverage additional funding from radiochemistry-related programs within DOE and elsewhere.

Publications, Presentations, and Patents

G.J.-P. Deblonde, J. Mattocks, Z. Dong, P. Wooddy, J. Cotruvo Jr., M. Zavarin. "Capturing an elusive but critical element: Natural protein enables actinium chemistry," Science Advances. In press. Accepted August 2021, (LLNL-JRNL-822758).

G.J.-P. Deblonde, J. Mattocks, H. Wang, E. Gale, A.B. Kersting, M. Zavarin, J. Cotruvo Jr. "Characterization of americium and curium complexes with the protein lanmodulin: a potential macromolecular mechanism for actinide mobility in the environment," Journal of the American Chemical Society, September 2021, DOI: 10.1021/jacs.1c07103, (LLNL-JRNL-824360).

G.J.-P. Deblonde, M. Zavarin, A.B. Kersting. "The coordination properties and ionic radius of actinium: A 120-year-old enigma," Coordination Chemistry Reviews, 2021, 446, 21413. DOI: 10.1016/j.ccr.2021.214130, (LLNL-JRNL-820222).

U.S. patent application 17/175,228. "Methods of sequestering target elements." Inventors: G.J.-P. Deblonde, Y. Jiao, D.M. Park, J.A. Mattocks, J. Cotruvo Jr. Publication date: 09/02/2021.

G.J.-P. Deblonde, J. Mattocks, Z. Dong, P. Wooddy, J. Cotruvo Jr., M. Zavarin. "Protein-Based Platform for Purification, Chelation, and Study of Medical Radiometals: Yttrium and Actinium," ChemRxiv, 2021, 14763426. DOI: 10.26434/chemrxiv.14763426.v1, (LLNL-JRNL-822758).

G.J.-P. Deblonde, "Spectrophotometric methods to probe the solution chemistry of lanthanide complexes with macromolecules." Book chapter in: Methods in Enzymology, vol. 651, page 1-22, Academic Press, 2021. DOI: 10.1016/bs.mie.2020.12.012, (LLNL-BOOK-815285).

G.J.-P. Deblonde. 2019. "Leveraging Polyoxometalates to Probe Actinide Chemistry." Annual Review of the Glenn T. Seaborg Institute, Idaho National Laboratory, October 2019, (LLNL-PRES-795478).