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Fundamental Chemistry Related to the Separations and Coordination of Actinium-225, Thorium-227, and Technetium-99

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Fundamental Chemistry Related to the Separations and Coordination of Actinium-225, Thorium-227, and Technetium-99 City University of New York (CUNY) CUNY Academic Works All Dissertations, Theses, and Capstone Projects Dissertations, Theses, and Capstone Projects 9-2018 Fundamental Chemistry Related to the Separations and Coordination of Actinium-225, Thorium-227, and Technetium-99 Jasmine L. Hatcher The Graduate Center, City University of New York How does access to this work benefit ou?y Let us know! More information about this work at: https://academicworks.cuny.edu/gc_etds/2891 Discover additional works at: https://academicworks.cuny.edu This work is made publicly available by the City University of New York (CUNY). Contact: [email protected] FUNDAMENTAL CHEMISTRY RELATED TO THE SEPARATIONS AND COORDINATION OF ACTINIUM-225, THORIUM-227, AND TECHNETIUM-99 by JASMINE LATOYA HATCHER A dissertation submitted to the Graduate Faculty in Chemistry in partial fulfillment of the requirements for the degree of Doctor of Philosophy, The City University of New York 2018 ©2018 JASMINE LATOYA HATCHER All Rights Reserved ii The Fundamental Chemistry Related to the Separations and Coordination of Actinium-225, Thorium-227, and Technetium-99 By Jasmine Latoya Hatcher This manuscript has been read and accepted for the Graduate Faculty in Chemistry to satisfy the dissertation requirement for the degree of Doctor of Philosophy Lynn C. Francesconi Date Chair of Examining Committee Brian R. Gibney Date Executive Officer iii Supervisory Committee: James F. Wishart Sharon Lall-Ramnarine Benjamin Burton-Pye Steve Greenbaum Elizabeth Biddinger Maria Contel iv ABSTRACT The Fundamental Chemistry Related to the Separations and Coordination of Actinium-225, Thorium-227, and Technetium-99 By Jasmine Latoya Hatcher This work explores the fundamental chemistry of actinium, thorium, and technetium in an effort to develop methodologies which help to address complications specific to each of these elements. Developing fundamental knowledge in inorganic chemistry has the power to meaningfully address a number of real world problems. By using simple systems and experiments like following an electron or changing the solvent system, we are able to gain invaluable information which can be used to address major issues. Actinium-225 (t½: 9.92 d) is an alpha-emitting radionuclide with nuclear properties well suited for alpha therapy of malignant tumors. The present global supply of 225Ac is 1.7 Ci per year yet the global demand is 50-100 Ci. Currently, the production of 225Ac from proton irradiation of 232Th metal targets is being investigated at Brookhaven National Laboratory. One proposed method for separation of 225Ac from bulk thorium targets involves the use of polyoxometalates (POMs), large metal oxide clusters that have been used to chelate high-valent 10- actinides and lanthanides. The modified Wells-Dawson POM ([P2W17O61] ) has a very high v affinity for thorium. Our study seeks to take advantage of the affinity of POMs for thorium to separate 225Ac from bulk thorium for 225Ac production. The separation is carried out by adding the POM to aqueous solutions of thorium, lanthanum, and actinium as individual metals and as mixed metal solutions, and contacting those solutions with 3% octylamine in chloroform. The extractions are quantified using ICP-OES. This study has shown that the POM completely extracts the thorium from the aqueous solution and preferentially extracts thorium over lanthanum and actinium. Thorium-227 (t½: 18.7 d) is an alpha emitting nuclide which may also be a candidate for targeted alpha therapy. With its longer half-life, 227Th delivers a lower dose of radiation over time, which may make it a better isotope for treating malignant tumors. Thorium has been found to treat ovarian and bone cancers in mice. In the past 3,4,3-LI(1,2-HOPO) was successfully coordinated to zirconium, found to exhibit high stability in vivo and ultimately built into an 89Zr- based imaging agent. Thorium and zirconium have very similar chemical behavior. Both are +4 oxophilic metals which prefer octadentate ligands. This work investigated the labeling and stability of Th-HOPO in comparison to the standard ligand for labeling, 1,4,7,10- tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA). It was found that HOPO had higher yields and higher stability. The development of radiolabeling methods required additional purification of the thorium to separate its many daughter radionuclides. Purification of the thorium was carried out using 8M nitric acid and an anion exchange resin. 99 5 Technetium-99 ( Tc, t½: 2.1 x 10 years; bmax: 293.7 keV) is a high-yield fission product (6%) in light-water reactors. The removal and permanent storage of technetium from nuclear waste streams is of great importance for the nuclear fuel cycle and for remediation of legacy waste. A fundamental study of the reduction, coordination, and spectroscopic behavior of vi technetium has been conducted in aqueous and organic media including ionic liquids (ILs). In order to ascertain the value of using ILs in nuclear waste remediation, the behavior of technetium in ILs must be understood. This work sought to understand the behavior of technetium, using electrochemistry and spectroscopy to investigate the behavior of well-known technetium complexes in neat ILs and acid-IL mixtures to probe the effect of ILs on technetium redox - chemistry. Titration of bistriflimidic acid (HNTf2) into TcO4 in the IL trimethylbutylammonium - bistriflimide (N1114 NTf2) showed that the TcO4 anion is protonated in the IL to form HTcO4 (pertechnic acid). This protonation was monitored using UV-Vis and x-ray absorption - spectroscopy, specifically, EXAFS and XANES, to understand the speciation of TcO4 in this IL. This study has found that technetium is more reactive in ILs. vii Acknowledgements First, I would like to acknowledge my advisor Lynn Francesconi. Thank you, Lynn, for all of your guidance and support and for taking a chance on a student who came out of nowhere and wanted to do research in radiochemistry. Thank you for the understanding and the tough love when I needed it most. Thank you for being an inspiration as a scientist, as a PI, and as a woman. I would also like to give my thanks and appreciation: To my committee members, thank you all for your patience and rapid responses when it came down to the wire. Steve Greenbaum: Thank you for the thought-provoking questions at the committee meetings, thank you for the NMR experiments and experience and, most importantly, thank you for the reality checks. Maria Contel: Thank you for allowing me to spend time with your group (my cousins) and learning inorganic synthesis Elizabeth Biddinger: Thank you for teaching me how to conduct electrochemistry in the glovebox. After learning how to adjust alligator clips with three layers of gloves on, I am confident that I can do anything in a glovebox. Benjamin Burton-Pye: Thank you for teaching me…well…everything I know about technetium synthesis and how not to contaminate myself in the lab. Also, thank you for being my first friend in graduate school (despite my reluctance). Here’s to many more years of friendship viii James Wishart: Thank you for your exhaustive edits on my thesis, I don’t think I’ve seen so much red ink in my life! My thesis is so much better for it. Thank you for inviting us back to BNL year after year. Thank you for employing me when I was still in denial about whether or not I was going to go to graduate school. Thank you for not letting me coast and get comfortable as a technician. Thank you for seeing the scientist in me that I didn’t see in myself. I hope that one day I will be as good of a chemist as you think I am. Thank you for the influence you’ve had on my life. Sharon Lall-Ramnarine: In order to properly thank you, I’d have to write another thesis. Unfortunately, I will not be doing this again so, here goes. Thank you, so very much, for seeing me. Thank you for taking me into a world that I never knew existed and that I never could have never imagined sitting in the back of my introductory chemistry classes. Thank you for pushing and not giving up when I resisted. In the summer of 2011, we debated on whether or not I should go to graduate school. I wasn’t sure I could make it through and you were convinced that could. I guess you were right. Thank you for not letting me win that argument. To members of the Francesconi past present and future: Thank you all so very much for the support and the laughs. The members of the MIRP Group at BNL: thank you all for welcoming me into your group in the last year of my Ph.D. To the Squeegee Crew: Thank you all for some of the best nights of my life. Thank you for the laughs and for always answering the call. To my family, who made this all possible: Mom and Lucien, thank you so very much for believing in me and giving me the space to figure it all out. You inspire me to be a better me. If I ix am half as good of a parent as you guys are, my children are going to be just fine. Lisa, thanks for setting the bar so darn high that I had to get a Ph.D. to just reach it! Thank you for being an inspiration. Wesley, thank you for your big heart and thank you for keeping your friends quiet while I was writing my thesis in the dining room. To My Fiancé, Felix, thank you for supporting me. Thank you for being there for ups and (break) downs. Thank for always being there to put me back together again.
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