Sahan R. Salpage* Ronald C. Lanzetta, Yan Zhou, Jamie C. Wang, Thomas E. Albrecht-Schmitt, and Kenneth Hanson There is growing interest and demand in search of novel approaches for separation of metal ions for reasons of both cost and public safety. For example, efficient and cost-effective purification of water and treatment of the existing radioactive waste could play a vital role towards sustainable use of resources.1,2 However, existing methods have often fall short when it comes to the separation of metal ions that have similar charge density, size, and binding affinities.3 Here, we report a novel photochemical separation strategy that relies on irreversible chemical transformations of the coordinating ligand, rather than the nature of the metal ion.4 Briefly, a ligand functionalized with a redox active benzenediazonium is bound to metal ions in solution. Then, complexes were selectively excited with monochromatic light. Excitation initiates photoinduced electron transfer (PET) from metal center to the functionalized ligand causes irreversible reduction of the diazonium moiety to N2 gas.5 The differences in polarity between the initial and reacted complexes were used to speciate two metals by means of chromatography. This opens the door to an entirely new separation strategy that does not rely on the solubility or binding affinity of the metal ion but instead on the intrinsically unique absorption spectrum of the metal complexes and the properties of the reacted ligand.

Light induced selective separation of metals with a redox active ligand

2019 Spring National Meeting

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