Instantaneous and Phosphine-Catalyzed Arene Binding and Reduction by U(III) Complexes

Area of Science:

• Organometallic Chemistry
• Actinide Chemistry
• Coordination Chemistry

Background:

• Neutral arenes are typically unsuitable ligands for electropositive actinide cations.
• Strongly reducing U(III) centers often exhibit anomalous spectral properties and limited reactivity.

Purpose of the Study:

• To investigate the reactivity of U(III) aryloxide complexes with neutral arenes.
• To characterize the resulting complexes and understand the reaction mechanism.

Main Methods:

• Synthesis of U(III) aryloxide complexes.
• Reaction with arenes under ambient conditions.
• Spectroscopic characterization (NMR, X-ray crystallography).

Main Results:

• Spontaneous binding and reduction of arenes by U(III) aryloxide complexes.
• Formation of unprecedented inverse arene sandwich (IAS) complexes.
• Observation of ligand redistribution and further arene reduction in some cases.
• Phosphine catalysis enabling isolation of asymmetric IAS complexes.

Conclusions:

• U(III) aryloxide complexes can readily activate and reduce neutral arenes, forming IAS complexes.
• These reactions explain previously observed anomalous properties of U(III) complexes.
• The findings expand the scope of actinide coordination chemistry and catalysis.