A Base-Free Terminal Actinide Phosphinidene Metallocene: Synthesis, Structure, Reactivity, and Computational Studies

Area of Science:

• Organometallic Chemistry
• Actinide Chemistry
• Phosphorus Chemistry

Background:

• Actinide metallocenes are crucial in catalysis and materials science.
• Stable phosphinidene complexes are rare, limiting their study.
• Understanding bonding in actinide complexes is key to predicting reactivity.

Purpose of the Study:

• To synthesize and characterize a novel base-free terminal actinide phosphinidene metallocene.
• To investigate the electronic structure and bonding properties of the synthesized complex.
• To explore the reactivity of the phosphinidene complex with various unsaturated substrates.

Main Methods:

• Synthesis via salt metathesis reaction of a thorium methyl iodide complex with Mes*PHK.
• Characterization of the product using spectroscopic and crystallographic techniques.
• Computational analysis using Density Functional Theory (DFT) to study bonding and reactivity.

Main Results:

• Isolation of the first stable, base-free terminal phosphinidene actinide metallocene, Cp‴₂Th═PMes*.
• DFT calculations reveal predominantly covalent bonding between the thorium and phosphinidene fragments.
• The complex reacts with CS₂, isothiocyanate, nitriles, isonitriles, and organic azides, but not alkynes.

Conclusions:

• The successful synthesis provides a new platform for exploring actinide phosphinidene chemistry.
• The observed reactivity patterns offer insights into the unique electronic nature of actinide phosphinidenes.
• This study advances the understanding of bonding and reactivity in f-element organometallic compounds.