Understanding the fundamental bonding interactions of selective <i>f</i>-element ligands presents a rich set of scientific challenges and is critical to the development of highly efficient separation reagents. Our approach uses the specific photophysical properties of trivalent lanthanides (Ln) and actinides (An) to study their selective binding and recognition by natural and synthetic hard oxygen-donor ligands. The photophysics and solution thermodynamic behavior of Ln(III) and An(III) complexes formed with selected siderophores and synthetic analogs such as multidentate hydroxypyridinonate ligands were probed. We report the first comprehensive characterization of sensitized Am(III) luminescence through the so-called antenna effect. In addition, while most investigated ligands were shown to sensitize the luminescence of one or several Ln(III) ions as well as that of Cm(III), subsequent specific binding of the metal complexes to secondary entities such as proteins that participate in endogenous metal homeostasis mechanisms resulted in significant enhancement of the intramolecular energy transfer processes. Particular metal-uptake pathways may therefore be used to create “double-antennas” for the sensitization of Ln(III) and An(III) luminescence. Such studies have important implications for the use of spectroscopic methods to exploit the fundamental knowledge of the role of <i>f</i>-electrons in actinide bonding for the development of new sequestering agents, separation technologies, and luminescence-based detection assays.

Specific recognition and enhanced luminescence sensitization of trivalent actinides

249th National Meeting (2015)

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