Department of Chemistry Seminar: Dr. Ivan Popov
About the event
Speaker: Ivan A. Popov, Assistant Professor
Department of Chemistry, Washington State University
Host: Dr. Eric Roalson
Title: Pushing Actinides to the Limit: Bonding and Reactivity at Extreme Oxidation States
Abstract: Separating heavy elements remains one of the central challenges in nuclear waste management. A detailed understanding of actinide-ligand interactions across multiple oxidation states is essential for the rational design of selective ligands for nuclear separations. The interplay between actinide-ligand covalency and reactivity at various oxidation states ultimately governs both selectivity and efficiency in these processes. In low-valent actinide complexes, enhanced metal-center reactivity requires sterically demanding ligands that can also act as electron reservoirs to accommodate excess electron density. Accurate deconvolution of the electronic structure of such species is therefore essential for rational ligand design. However, the energetic proximity of the actinide 5f and 6d manifolds to ligand-based antibonding orbitals makes this task non-trivial, as strong metal-ligand electron delocalization blurs oxidation-state assignments while also enabling unusual reaction pathways. In contrast, at high oxidation states, the actinide 5f orbitals are progressively stabilized with increasing oxidation state and atomic number, leading to substantial mixing with ligand orbitals and enhanced covalency. Improved orbital energy matching shifts the balance between overlap-driven and energy-degeneracy-driven covalency, giving rise to divergent reactivity patterns in later actinides and modulating key thermodynamic parameters, such as pKa, bond dissociation free energies, and redox potentials. In this talk, I will present collaborative theoretical and experimental studies that elucidate these relationships between covalency and reactivity in low-valent uranium-arene and high-valent actinide-imidophosphorane complexes.
Brief Biography: Ivan A. Popov received his B.S. and M.S., with honors, in chemistry from RUDN University (Moscow, Russia). In 2011, he moved to the United States to pursue doctoral studies under the supervision of Prof. Alexander I. Boldyrev at Utah State University, where he earned his Ph.D. in theoretical physical chemistry. In June 2017, Ivan joined the Theoretical Division at Los Alamos National Laboratory as a Director’s Postdoctoral Fellow. In February 2018, he was awarded the J. R. Oppenheimer Distinguished Postdoctoral Fellowship. In 2021, Ivan began his independent career as an Assistant Professor at the University of Akron, where he served for three years before joining the Department of Chemistry at Washington State University. In 2023, he received federal funding from the National Nuclear Security Administration (NNSA) through the Transuranic Chemistry Center of Research Excellence (TRUCoRE) to elucidate the electronic structure of actinide compounds in extreme oxidation states and transuranic hydrides. Ivan has also received college- and university-level recognition, including the Buchtel College of Arts and Sciences Early Research and Creativity Award at the University of Akron and the Meyer Early Career Launch Fellowship at Washington State University.