A binuclear thorium complex with a Th-O-Th unit.

Area of Science:

• Organometallic Chemistry
• Inorganic Chemistry
• Materials Science

Background:

• Thorium complexes are of interest due to their unique electronic properties and potential applications.
• Understanding bonding in thorium-oxo systems is crucial for predicting reactivity and stability.
• The Trapen ligand provides a robust coordination environment for metal ions.

Purpose of the Study:

• To synthesize and characterize a novel binuclear thorium complex with an oxo bridge.
• To investigate the electronic structure and bonding characteristics of the Th-O-Th unit.
• To compare the covalent character of Th-O bonds with Th-N bonds.

Main Methods:

• Synthesis of thorium complexes using the Trapen ligand and sodium azide.
• Reductive treatment with KC8 to form the oxo-bridged dimer.
• X-ray crystallography for structural determination of the binuclear complex.
• Density functional theory (DFT) calculations to analyze bonding.

Main Results:

• A dimeric thorium complex [(Trapen^TMSN₃Th)₂] was formed from a thorium chloride precursor.
• Treatment with KC8 yielded the binuclear oxo-bridged thorium complex [(Trapen^TMSTh)₂(µ-O)].
• Crystal structure revealed a symmetrical Th-O-Th unit with a Th-O bond length of 2.271(2) Å.
• DFT calculations indicated significant covalent character in the Th-O-Th interaction.

Conclusions:

• The synthesis provides a new route to binuclear thorium complexes.
• The Th-O-Th bond exhibits substantial covalent character, exceeding that in analogous Th-N-Th systems.
• The findings contribute to understanding bonding in thorium-oxo compounds and their electronic properties.