Lanthanide-Nitrogen Triple Bonds

Area of Science:

• Inorganic Chemistry
• Materials Science
• Quantum Chemistry

Background:

• Lanthanide-ligand multiple bonds are challenging to stabilize due to the inherent ionic nature of lanthanide metals.
• The solid-state synthesis of lanthanide complexes with lanthanide-nitrogen triple bonds has been a long-standing goal in chemistry.

Purpose of the Study:

• To achieve the first stabilization of a lanthanide-nitrogen triple bond in the solid state.
• To characterize the structure and electronic properties of the synthesized complex.

Main Methods:

• Solid-state synthesis of a lanthanide complex.
• Single-crystal X-ray diffraction for structural analysis.
• Quantum-chemical calculations for electronic structure investigation.

Main Results:

• Successful synthesis and characterization of a diatomic monocation CeN+ within a nitrogen-substituted carbon cage (CeN@C81N).
• Experimental confirmation of Ce≡N triple bonds with a bond length of 1.76 Å, significantly shorter than previously reported double bonds.
• Quantum-chemical studies revealed a formal Ce4+ valence state and significant 4f electron contribution to the triple bond.

Conclusions:

• This study reports the first stable solid-state lanthanide-nitrogen triple bond.
• The findings demonstrate a novel electronic structure with intramolecular single-electron transfer, challenging previous understandings of lanthanide bonding.