Dr. Karah Knope, Provost’s Distinguished Associate Professor, Georgetown University
Group website: https://knopelab.com/
Research Interests:
Our group is broadly interested in self-assembly processes, phase formation, and structure-property relationships in f-element materials. All projects have a significant synthetic component and involve the characterization of new materials. Current research areas include:
Lanthanide based inorganic and inorganic-organic hybrid materials
Our group is developing new synthetic strategies to access crystalline mixed lanthanide-transition metal oxide based materials that are targeted for their promising spectroscopic and magnetic properties. Areas of research include the synthesis and design of inorganic and hybrid organic-inorganic frameworks and supramolecular assemblies, structure elucidation, characterization (spectroscopic, magnetic, thermal behavior, etc) and correlation of structure property relationships.
Actinide-organic interactions
Our group is also examining the interactions of the early actinides (Th, U) with biochemically and geochemically relevant functional groups. We are exploring the speciation and structural chemistry of actinide-organic ligand complexes in solution and the solid state using spectroscopic techniques, a number of synthetic methods, and solid state structural characterization including single crystal and powder X-ray diffraction. We are interested in correlating the solution species with those observed in the solid state as this can serve as a basis upon which to build a fundamental understanding of the chemical behavior of the actinides. Of particular interest are precipitation, complexation, and redox reactions that occur in aqueous solution and under the influence of functionally relevant organic ligands. Such insight into the coordination and reactivity of the actinides has important implications for the transport and fate of heavy elements in the environment.
Abstract for seminar: Metal-oxo phases, including clusters and nanoparticles, play a crucial role in advancing both the fundamental and applied aspects of f-element chemistry. Despite extensive research over the past several decades, our understanding of lanthanide and actinide cluster chemistry remains limited. In the case of actinides, polynuclear species have long been recognized as a major challenge in achieving accurate thermodynamic modeling. From an applied perspective, the formation of cluster compounds and nanoparticles complicates efforts to predict and control actinide behavior under conditions relevant to waste management and environmental transport. Our understanding of lanthanide cluster formation and stability is similarly lacking. Lanthanide-hydroxo clusters have drawn considerable attention due to their valuable material properties, leading to a substantial body of reported compounds. However, a clear, rational approach to the synthesis of these phases has yet to be established. While the motivations for studying lanthanide and actinide-oxo clusters may differ, the overarching challenge is the same: to define the conditions and parameters that govern their formation and stability. Advancing this knowledge would not only deepen our understanding of their chemical properties but may also unlock new opportunities in fields such as separations. To address these challenges, our group has been investigating the factors that drive homo- and heterometal f-element cluster formation and stabilization. This presentation will highlight recent work from our lab on the synthesis, characterization, and reactivity of lanthanide and actinide cluster compounds, with a focus on trends in their formation, structure, and behavior.