Light-Promoted C(sp³)-C(sp³) Reductive Elimination from Dialkyl Ni^II Complexes

Area of Science:

• Organometallic Chemistry
• Photochemistry
• Catalysis

Background:

• Nickel-catalyzed cross-coupling is vital for forming carbon-carbon bonds.
• Direct C(sp³)-C(sp³) bond formation via reductive elimination from Ni(II) is typically difficult.
• Existing methods often require highly oxidized nickel species or specific ligand designs.

Purpose of the Study:

• To investigate the mechanism of light-induced C(sp³)-C(sp³) bond formation.
• To explore the use of light activation for Ni(II) complexes in cross-coupling.
• To elucidate the role of photolysis and radical rebound in this process.

Main Methods:

• Organometallic studies
• Spectroscopic analysis
• Computational modeling
• Wavelength-dependent quantum yield measurements
• Ligand electronics-reactivity studies
• Crossover product distribution analysis

Main Results:

• Evidence supports a photolysis/radical rebound mechanism for light-induced C(sp³)-C(sp³) coupling.
• Quantum yields and ligand effects provide insights into the reaction pathway.
• Computational studies determined reaction barriers.
• Crossover studies confirmed the proposed mechanism.

Conclusions:

• Light-induced reductive elimination from Ni(II) is a viable strategy for C(sp³)-C(sp³) bond formation.
• This photochemical approach complements existing thermal methods.
• The photolysis/radical rebound mechanism expands the toolkit for challenging cross-coupling reactions.