Modeling Mo(VI)═O Biologically Related Interactions with Oximes and Hydroxylamines: Implications for Uranium Seawater...

Area of Science:

• Inorganic Chemistry
• Biogeochemistry
• Materials Science

Background:

• Molybdenum enzymes are vital for nitrogen cycle processes.
• The reduction mechanism of Mo(VI) by hydroxylamine and oximes is not fully understood.
• Oxime-based sorbents are used for uranium extraction from seawater.

Purpose of the Study:

• To elucidate the mechanism of Mo(VI) reduction by hydroxylamine/oximes.
• To investigate the implications for oxime-based sorbents in uranium extraction.
• To challenge the prevailing view on molybdenum redox reactions.

Main Methods:

• Isolation and characterization of a novel Mo(VI)-oxido-hydroxylamido complex.
• Experimental techniques including NMR, ESI-MS, XPS, and FT-IR.
• Density Functional Theory (DFT) calculations.

Main Results:

• First isolation of the Mo(VI)-oxido-hydroxylamido complex: [MoVI(O)(η2-NH2O)]3+.
• Elucidation of the Mo(VI) to Mo(II)-NO conversion mechanism.
• Demonstration that Mo(VI) is unlikely to degrade uranium oxime-based extraction materials in seawater.

Conclusions:

• Provides fundamental insight into molybdenum-oxime reactivity.
• Offers a molecular basis for designing robust oxime-functionalized materials for uranium extraction.
• Challenges long-held assumptions about molybdenum redox chemistry.