A masked two-coordinate cobalt(I) complex that activates C-F bonds

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Ligand Design

Background:

• Low-coordinate metal complexes are crucial for catalytic applications.
• Bulky ligands are often employed to stabilize reactive metal centers.
• Understanding ligand binding modes is key to controlling reactivity.

Purpose of the Study:

• To isolate and characterize a novel unsaturated cobalt complex with a bulky beta-diketiminate ligand.
• To investigate the unusual slipped arene binding mode and its interconversion with traditional ligation.
• To demonstrate the utility of this complex as a synthon for low-coordinate cobalt(I) and its reactivity towards C-F bond cleavage.

Main Methods:

• Isolation and full characterization of the L(tBu)Co complex.
• Kinetic studies to elucidate the mechanism of ligand isomerization.
• Reactivity studies, including C-F bond activation of fluorobenzene.

Main Results:

• Successful isolation and characterization of L(tBu)Co.
• Discovery of a rapidly interconverting slipped κN,η(6)-arene and traditional κ(2)N,N' binding modes.
• Demonstration of L(tBu)Co as a stable yet reactive synthon for low-coordinate cobalt(I).
• Evidence of C-F bond cleavage in fluorobenzene by the complex.

Conclusions:

• The bulky beta-diketiminate ligand enables a "masked" two-coordinate cobalt(I) species.
• Ligand isomerization is reversible and controlled by Lewis base coordination.
• L(tBu)Co represents a valuable new tool for exploring low-coordinate cobalt chemistry and C-F bond activation.