Double lecture on f-block chemistry
Ilja Popovs, Nuclear Engineering, University of Tennessee:
Designing Smart Molecules and Materials for Separations
Abstract
Ilja Popovs, Nuclear Engineering, Uni. Tennessee: Designing Smart Molecules and Materials for Separations.
Every molecule has a purpose, but designing one that can selectively recognize and hold onto a specific metal ion in water remains a central challenge in modern chemistry. In this talk, I will show how coordination chemistry and separation science come together to build “smart” ligands and materials that bind specific metal ions for a variety of applications.
A key theme is ligand preorganization, where we design rigid, shape-matched binding cavities that reduce the energetic cost of encapsulating a metal, promote faster complex formation, and yield more inert complexes under physiological conditions. We will also discuss subtle trends across the lanthanide series, especially the lanthanide contraction, the gradual decrease in ionic radius from La to Lu, which creates measurable differences in coordination behavior that can be leveraged for selectivity. By tuning molecular shape, charge, and donor groups, we can control stability and metal preference, enabling new paradigms in f-element separations and applications.
Biography
Ilja Popovs is an Associate Professor and Pietro F. Pasqua Faculty Fellow in the Department of Nuclear Engineering at the University of Tennessee, Knoxville (UTK).
He has more than 15 years of experience spanning synthesis and catalysis, materials science, nuclear and radiochemistry, electrochemistry, process design, and advanced chemical separations. His research integrates fundamental coordination chemistry, advanced spectroscopy, and ligand discovery to develop innovative chelators for radiotheranostic applications and separation and purification technologies for f-elements and other radionuclides. He has authored over 70 peer-reviewed publications and holds several patents.
His work has been recognized with multiple R&D 100 Awards, UT–Battelle research honors, and national media coverage.
Alex Ivanov, Nuclear Engineering, University of Tennessee:
Exploring Actinide Covalency in Extreme Environments
Abstract
Molten salt reactors (MSRs) represent a promising pathway to-ward safer, more efficient, and more sustainable nuclear energy systems.
Achieving their full potential, however, requires a detailed understanding of the complex chemical processes occurring within high-temperature molten salts, particularly uranium speciation and its separation from fission products. In our recent study of molten uranium trichloride (UCl₃), we combined advanced experimental techniques with first-principles computational modeling to probe its atomic-scale structure and bonding.
Our results revealed unexpected chemical behavior: the emergence of short-lived, partially covalent U–Cl interactions driven by increased participation of uranium 5f valence orbitals. Rather than behaving as a simple ionic melt, molten UCl₃ exhibits a dynamically heterogeneous bonding environment with distinct inner and outer coordination shells.
Biography
Alex Ivanov is an Assistant Professor and Early Career Faculty Fellow in the Department of Nuclear Engineering at the University of Tennessee, Knoxville, USA.
Dr. Ivanov’s research broadly focuses on the development and application of neutron and X-ray scattering and spectroscopy techniques, as well as theoretical and computational methods, to investigate processes and functional materials for energy-relevant technologies, including chemical separations, radionuclides, nuclear materials, and sustainability.
His recent projects include fundamental investigations of lanthanides and actinides in condensed matter and elucidating the coordination chemistry of radiopharmaceutical compounds using synchrotron X-ray absorption spectroscopy.
He has authored more than 80 peer-reviewed publications, several DOE technical reports, and U.S. patents spanning nuclear separations, radiochemistry, and molten salt technologies. He has received multiple institutional and national recognitions for research excellence, teaching, and science communication throughout his career.