Exploring Metal-Ligand Interactions and Predicting Stability Constants in Uranyl Nitrate Complexes with Alkyl...

Area of Science:

• Computational Chemistry
• Inorganic Chemistry
• Materials Science

Background:

• Trialkyl phosphates are crucial in nuclear fuel reprocessing.
• Understanding their complexation with uranyl nitrate is vital for process optimization.
• Previous studies have explored various aspects of these interactions.

Purpose of the Study:

• To investigate the complexation behavior of diverse trialkyl phosphates with uranyl nitrate.
• To elucidate the influence of alkyl substituent symmetry on complex stability.
• To predict the stability constants of these metal complexes.

Main Methods:

• Density functional theory (DFT) was employed for quantum chemical calculations.
• Energy decomposition analysis (EDA) was used to assess binding energies and strain.
• Stability constants were predicted computationally.

Main Results:

• Phosphorus and phosphoryl oxygen charges are largely independent of alkyl substituents.
• Strain energy from geometric deformation significantly impacts complex formation.
• Complexes with symmetrical ligands exhibit more negative binding energies than unsymmetrical ones.
• The predicted stability constant for tributyl phosphate (TBP) with uranyl nitrate (2.3) closely matches the experimental value (1.9).

Conclusions:

• Alkyl substituent symmetry is a key factor in the stability of uranyl nitrate-trialkyl phosphate complexes.
• DFT and EDA provide valuable insights into the electronic and energetic aspects of complexation.
• Computational predictions of stability constants show good agreement with experimental data, validating the methodology.