Solid-State Structure of Tris-Cyclopentadienide Uranium(III) and Plutonium(III)

Area of Science:

• Organometallic Chemistry
• Actinide Chemistry
• Solid-State Chemistry

Background:

• Organometallic tris-cyclopentadienide actinide(III) (AnCp₃) complexes have been known for 50 years.
• Only the NpCp₃ solid-state structure was previously characterized.
• Limited structural data hinders understanding of bonding in AnCp₃ systems.

Purpose of the Study:

• To determine and report the solid-state structures of UCp₃ and PuCp₃.
• To compare the structures of AnCp₃ complexes with their lanthanide analogues.
• To investigate trends in bonding covalency within AnCp₃ complexes.

Main Methods:

• X-ray crystallography for solid-state structure determination of UCp₃ and PuCp₃.
• Theoretical calculations to support structural models.
• Comparative analysis with known lanthanide complexes.

Main Results:

• UCp₃ and PuCp₃ were found to be isostructural with NpCp₃.
• Structural models were validated by theoretical computations.
• Observed trends in bond lengths suggest increased covalency in AnCp₃ compared to lanthanides.

Conclusions:

• The solid-state structures of UCp₃ and PuCp₃ are now elucidated.
• These findings provide structural insights into actinide(III) organometallic complexes.
• Increased covalency in AnCp₃ bonding is indicated, differing from lanthanide analogues.