Predicting stability constants for uranyl complexes using density functional theory.

Area of Science:

• Computational Chemistry
• Coordination Chemistry
• Nuclear Chemistry

Background:

• Rational ligand design requires accurate prediction of uranyl complex stability.
• Equilibrium constants (log K1) are crucial for assessing uranyl affinity and selectivity.
• Previous theoretical methods offered good relative binding estimates but struggled with absolute values.

Purpose of the Study:

• To compute aqueous stability constants for uranyl complexes using computational methods.
• To develop accurate predictive models for absolute log K1 values.
• To demonstrate the utility of these models for screening novel uranyl-binding ligands.

Main Methods:

• Density functional theory (B3LYP) calculations.
• Integral equation formalism polarizable continuum model (IEF-PCM) for aqueous solvation.
• Fitting experimental data to establish correlations for specific ligand types.

Main Results:

• Theoretical calculations provided good relative binding strength estimates.
• Absolute log K1 values were initially overestimated.
• Correlations derived from experimental data enabled accurate prediction of absolute log K1 values (RMSD < 1.0).

Conclusions:

• Correlated computational methods can accurately predict uranyl/ligand complex stability constants.
• This approach facilitates the rational design of ligands with enhanced uranyl affinity.
• The method is effective for screening amidoxime and imide dioxime ligands for uranyl chelation.