Actinide covalency measured by pulsed electron paramagnetic resonance spectroscopy.

Area of Science:

• Inorganic Chemistry
• Quantum Chemistry
• Materials Science

Background:

• Actinide chemical bonding understanding significantly lags behind other elements, hindering technological and fundamental research.
• Covalency, the sharing of electrons between f-block elements and ligands, is crucial for understanding chemical differences but lacks direct measurement in actinides.

Purpose of the Study:

• To report the first direct measurements of covalency in actinide compounds.
• To quantify electron-spin density at ligand nuclei in thorium(III) and uranium(III) species.
• To advance the understanding of actinide chemical bonding and reactivity.

Main Methods:

• Utilized pulsed electron paramagnetic resonance (EPR) spectroscopy.
• Applied the hyperfine sublevel correlation technique for precise measurements.
• Analyzed weak hyperfine interactions to determine electron-spin density.

Main Results:

• Successfully obtained the first pulsed EPR spectra for actinide compounds.
• Quantified the extent of covalency in molecular thorium(III) and uranium(III) species.
• Established a direct link between measured electron-spin density and covalency.

Conclusions:

• Pulsed EPR and hyperfine sublevel correlation provide direct measures of actinide covalency.
• This work establishes a foundation for understanding actinide chemical bonding and reactivity.
• Future studies can leverage these methods to explore a wider range of actinide complexes.