Early Lanthanide(III) Ate Complexes Featuring Ln-Si Bonds (Ln = La, Ce): Synthesis, Structural Characterization, and...

Area of Science:

• Organometallic Chemistry
• Lanthanide Chemistry
• Silicon Chemistry

Background:

• Research on lanthanide (Ln) complexes with silyl ligands is growing but unbalanced across Ln elements.
• Silyl lanthanum and cerium complexes are less explored compared to Sm and Yb.
• No solid-state structure of a silyl lanthanum complex was previously reported.

Purpose of the Study:

• To synthesize and structurally characterize novel silyl lanthanum and cerium ate complexes.
• To investigate the electronic and bonding properties of lanthanide-silicon bonds in these complexes.
• To address the gap in knowledge regarding silyl complexes of lighter lanthanides.

Main Methods:

• Synthesis of four types of ate complexes using alkali metal silanides.
• Structural characterization via X-ray diffraction.
• Solid-state 29Si NMR spectroscopy for diamagnetic lanthanum complexes.
• Computational studies (DFT) to analyze bonding.

Main Results:

• Successfully synthesized and structurally characterized four types of silyl lanthanum and cerium ate complexes.
• Determined La-Si and Ce-Si bond lengths, finding them comparable to related lanthanide complexes.
• Observed large one-bond hyperfine splitting constants in 29Si NMR of silyl lanthanum complexes.
• Computational studies indicated a polarized covalent character for Ln-Si bonds.

Conclusions:

• The study expands the known chemistry of silyl lanthanum and cerium complexes.
• Structural and spectroscopic data provide insights into Ln-Si bonding.
• Findings support the polarized covalent nature of lanthanide-silicon bonds in these ate complexes.