Synthesis and Characterization of Acyclic Schiff Bases and Redox Active Chelation of Actinides

Nuclear power is used to generate low carbon emissive energy. However, despite the significant positives of reducing the usage of fossil fuels, the storage and remediation of the waste generated is still a pertinent issue, given the danger it presents to the environment through contamination and spillage. Therefore, the continued exploration of the fundamental character of actinides is highly imperative so that the design of the technology and methodology can be further developed to improve the safety of nuclear power. In this regard, the goal is to develop ligands that can competitively bind and act as sensors to uranyl (UO22+), while providing insights to the bonding interactions of the actinide. Synthesizing and designing modular mixed donor ligands, “Schiff Bases,” enables us to deconvolute the enigmatic characteristics of the ion. The acyclic macromolecule (Pyrrophen) which integrate pyrroles alongside Schiff bases and carbonyl oxo groups was designed previously, and its selectivity for uranyl compared to other transition metals and lanthanides. Of great interest is the coordinative properties and ability to accommodate the binding sites of smaller ions, which then presents a distinct spectrochemical emission. These properties were applied to the transuranic ion, neptunyl (NpO22+), to compare the ligand’s chelating abilities and emergent emissive properties, given that neptunyl is a biproduct of the fissile fuel cycle. Exchanging the benzyl ester moieties of the ligands for amide containing substituents, we can observe the competitive binding of new ligands for uranyl in non-aqueous media. Studies of the effect of anionic coordination and electronic density donation using derivatives of mono-halogenated naphthylsalophens allows us to better understand the electronic communication between the metal and ligand. The findings of these studies allow insight into the unique characteristics of the uranyl and can inform further development of the electronic manipulation of the actinide.