Tuning amidoximate to enhance uranyl binding: a density functional theory study

Area of Science:

• Materials Science
• Computational Chemistry
• Environmental Chemistry

Background:

• Amidoxime functionalized sorbents show potential for uranium extraction from seawater.
• The underlying electronic interactions governing this affinity are not fully understood.

Purpose of the Study:

• To investigate the electronic effects of amidoximate ligands bound to the uranyl cation (UO2^2+).
• To understand the electronic structure for enhancing amidoxime binding and developing selective sorbents.

Main Methods:

• Density functional theory (DFT) calculations were performed on uranyl-amidoximate derivatives.
• Structural, electronic, and thermochemical properties were investigated.
• Computational findings were validated against experimental data.

Main Results:

• Computational results closely matched experimental data, with bond length errors under 0.07 Å.
• Binding strength directly correlates with electron donation, as shown by Hammett constant analysis.
• Two novel imidazole-derived oximes demonstrated superior binding strength compared to amidoximate derivatives.

Conclusions:

• Electron donation is a key factor in enhancing uranyl binding affinity.
• Imidazole-derived oximes represent a promising class of sorbents for efficient uranium extraction.
• This research provides a foundation for designing more effective uranium capture materials.