An Approach to Carbide-Centered Cluster Complexes.

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Materials Science

Background:

• Carbide ligands typically exhibit limited coordination modes due to steric hindrance.
• Previous research focused on mononuclear or simpler multinuclear carbide complexes.
• Bimetallic carbonyl complexes offer unique proximity for ligand interactions.

Purpose of the Study:

• To explore the coordination behavior of carbide ligands in novel multinuclear complexes.
• To synthesize and characterize new trimetallic carbide complexes involving ruthenium, iron, and cobalt.
• To investigate the role of bimetallic carbonyl complexes in facilitating unusual ligand coordination.

Main Methods:

• Synthesis of trimetallic complexes (Cy₃P)₂Cl₂Ru═CFe₂(CO)₈ (RuCFe₂) and (Cy₃P)₂Cl₂Ru═CCo₂(CO)₇ (RuCCo₂).
• Characterization using Nuclear Magnetic Resonance (NMR) spectroscopy.
• Verification through Mössbauer spectroscopy and X-ray crystallography.

Main Results:

• The carbide ligand in the ruthenium complex adopted a μ₃ coordination mode, bridging three metal centers.
• Trimetallic complexes RuCFe₂ and RuCCo₂ were successfully formed by reacting the ruthenium carbide precursor with Fe₂(CO)₉ and Co₂(CO)₈, respectively.
• Bridging carbonyl ligands were expelled from the iron and cobalt complexes to accommodate the carbide ligand.

Conclusions:

• This work presents the first examples of carbide ligands acting as μ₃ ligands.
• The proximity of metal-metal bonds in bimetallic carbonyl complexes enables the formation of these unique trinuclear structures.
• The findings expand the known coordination chemistry of carbide ligands and offer new avenues for designing complex metal clusters.