Molecular Thorium Trihydrido Clusters Stabilized by Cyclopentadienyl Ligands

Area of Science:

• Organometallic Chemistry
• Thorium Chemistry
• Coordination Chemistry

Background:

• Thorium complexes with cyclopentadienyl ligands are important in catalysis and materials science.
• Understanding the reactivity and structural diversity of thorium hydrides is crucial for advancing actinide chemistry.

Purpose of the Study:

• To synthesize and characterize novel molecular thorium trihydrido complexes.
• To investigate the influence of cyclopentadienyl ligand sterics on thorium hydride cluster nuclearity.
• To explore the hydrogenolysis of thorium tribenzyl complexes.

Main Methods:

• Hydrogenolysis of thorium tribenzyl complexes.
• Isolation and characterization of products using NMR spectroscopy and single-crystal X-ray diffraction.
• Confirmation of hydride positions via neutron diffraction and DFT calculations.

Main Results:

• The first examples of molecular thorium trihydrido complexes with varying nuclearities were synthesized.
• The nuclearity of the thorium hydride clusters was found to depend on the steric properties of the cyclopentadienyl ligands.
• A tetra-nuclear octahydrido thorium dibenzylidene complex was isolated as a hydrogenolysis intermediate.

Conclusions:

• Steric effects of cyclopentadienyl ligands play a key role in determining the nuclearity of thorium hydride clusters.
• Hydrogenolysis provides a viable route to novel thorium hydride complexes.
• Comprehensive characterization confirms the structures and bonding in these unique thorium compounds.