Complexation of uranium(VI) with aromatic acids in aqueous solution: a combined computational and experimental study

Area of Science:

• Inorganic Chemistry
• Computational Chemistry
• Spectroscopy

Background:

• Uranium(VI) complexes are crucial in nuclear chemistry and materials science.
• Understanding ligand coordination is key to predicting complex behavior.
• Computational and experimental methods offer complementary insights.

Purpose of the Study:

• To investigate uranium(VI) complexes with salicylhydroxamate, benzohydroxamate, and benzoate.
• To determine the coordination mode of salicylhydroxamate to the uranyl ion.
• To validate computational methods against experimental data.

Main Methods:

• Density functional theory (DFT) for structural and electronic properties.
• Time-dependent DFT (TD-DFT) for excitation spectra.
• Extended X-ray absorption fine structure (EXAFS) spectroscopy for experimental validation.

Main Results:

• Calculated molecular structures and relative stabilities agreed well with experimental data.
• TD-DFT calculations accurately reproduced experimental excitation spectra.
• Salicylhydroxamate was identified to coordinate via hydroxamic acid oxygen atoms, not phenolic oxygen or nitrogen.

Conclusions:

• Combined computational and experimental approaches provide reliable characterization of uranium(VI) complexes.
• Solvation effects are critical for accurate agreement between computational and experimental results.
• The coordination mode of salicylhydroxamate to uranyl ion was definitively established.