Formation and characterization of the uranyl-SO2 complex, UO2(CH3SO2)(SO2)-

Area of Science:

• Inorganic Chemistry
• Organometallic Chemistry
• Computational Chemistry

Background:

• Uranyl complexes are crucial in nuclear fuel cycles and environmental remediation.
• Understanding the reactivity of uranyl ions with small molecules like SO(2) is vital for predicting their behavior.
• Previous studies have not fully elucidated the coordination and electronic structure of uranyl-SO(2) adducts.

Purpose of the Study:

• To synthesize and characterize a novel uranyl-sulfur dioxide adduct.
• To investigate the reaction of this adduct with molecular oxygen.
• To determine the electronic structure and coordination of the uranyl-SO(2) complex using computational methods.

Main Methods:

• Synthesis and characterization of the uranyl-SO(2) adduct via mass spectrometry.
• Collision-induced dissociation experiments in an ion trap.
• Density functional theory (DFT) calculations at the B3LYP level.
• Analysis of geometric parameters and vibrational frequencies.

Main Results:

• The uranyl-SO(2) adduct, UO(2)(CH(3)SO(2))(SO(2))(-), was successfully prepared and identified.
• Collision-induced dissociation yielded the target adduct, which reacted with O(2) to form UO(2)(CH(3)SO(2))(O(2))(-), releasing SO(2).
• DFT calculations predicted a triplet ground state and revealed SO(2) coordination through two oxygen atoms, consistent with U(V) oxidation state.

Conclusions:

• The uranyl-SO(2) adduct represents a U(V) species coordinated by SO(2)(-) and CH(3)SO(2)(-) anions.
• Reaction with O(2) leads to oxidation of U(V) to U(VI) and formation of a peroxo ligand, with SO(2) extrusion.
• This study provides new insights into the redox chemistry and coordination behavior of uranyl complexes.