Constructing reactive Fe and Co complexes from isolated picolyl-functionalized N-heterocyclic carbenes

Area of Science:

• Organometallic Chemistry
• Catalysis
• Green Chemistry

Background:

• N-heterocyclic carbenes (NHCs) are crucial ligands in organometallic chemistry.
• Low-coordinate metal complexes offer unique reactivity.
• Catalytic reduction of ketones is important in organic synthesis.

Purpose of the Study:

• To synthesize novel picolyl-functionalized NHCs.
• To explore their use as precursors for low-coordinate iron and cobalt complexes.
• To investigate the catalytic activity of these complexes in ketone hydrosilylation.

Main Methods:

• Isolation of free picolyl-functionalized NHCs.
• Synthesis of four-coordinate iron and cobalt complexes.
• Catalytic testing of complexes for ketone hydrosilylation using polymethylhydrosiloxane (PMHS).

Main Results:

• Successful isolation of picolyl-NHC precursors.
• Formation of low-coordinate iron and cobalt complexes.
• Demonstration of efficient catalytic ketone reduction by an iron complex at low catalyst loadings (0.05-1 mol%) using PMHS at ambient temperature.

Conclusions:

• Picolyl-functionalized NHCs are effective precursors for catalytically active iron and cobalt complexes.
• The developed iron complex enables fast and efficient catalytic reduction of ketones.
• This methodology offers a sustainable approach to ketone reduction using an inexpensive industrial byproduct.