The synthesis and spectroscopic characterization of an aromatic uranium amidoxime complex

A tridentate aromatic amidoxime ligand and its corresponding uranyl complex have been synthesized. The complex was rigorously characterized with single-crystal X-ray diffraction, solid-state NMR, infrared absorption, and Raman spectroscopy. Unlike previous amidoxime complexes, the crystal structure confirms the complexation of only a single tridentate amidoxime ligand to the uranium, and solid state NMR confirms uranyl binding in the bulk sample. The Raman spectrum of the complex is dominated by the strong UO vibration which exhibits a significant shift from the UO vibration in unbound uranyl. Density functional theory (DFT) aided in calculations of vibrational modes as well as providing insight into the electronic structure of this uranyl complex.