Cobalt Boryl Complexes: Enabling and Exploiting Migratory Insertion in Base-Metal-Mediated Borylation.

Area of Science:

• Organometallic Chemistry
• Inorganic Chemistry

Background:

• Cobalt boryl complexes are rarely reported.
• Understanding M-B bond nature is crucial for reactivity.

Purpose of the Study:

• To systematically synthesize cobalt boryl complexes.
• To investigate the influence of trans ligands on M-B bond stability and reactivity.
• To explore boryl transfer reactions using base-metal complexes.

Main Methods:

• Synthesis of cobalt boryl complexes with varying trans ligands (strong σ-donor vs. CO).
• Characterization of M-B bond properties under different electronic conditions.
• Investigation of reactivity, including acid stability and CO migratory insertion.

Main Results:

• Remarkable and controllable variation in cobalt-boron (Co-B) bond nature achieved.
• Complexes with strong trans σ-donors exhibit high inertness, retaining the Co-B bond in strong acid.
• The π-acceptor CO ligand in the trans position labilizes the boryl ligand via migratory insertion, enabling coordinative unsaturation.

Conclusions:

• Cobalt boryl complexes offer tunable reactivity through ligand design.
• CO migratory insertion in cobalt boryl complexes provides access to reactive intermediates.
• This base-metal chemistry facilitates alkene functionalization via boryl transfer, similar to noble metal catalysis.