Bringing Homogeneous Iron Catalysts on the Heterogeneous Side: Solutions for Immobilization.

Area of Science:

• Catalysis
• Materials Science
• Green Chemistry

Background:

• Noble metal catalysts are prevalent but costly and toxic.
• Iron catalysts offer a sustainable, biocompatible, and versatile alternative.
• Heterogeneous iron catalysts are desirable for industrial applications over homogeneous systems.

Purpose of the Study:

• To review and discuss approaches for heterogenizing iron catalysts over the past two decades.
• To highlight the utility and critical aspects of various iron catalyst immobilization strategies.
• To explore the application of heterogeneous iron catalysts in diverse chemical transformations.

Main Methods:

• Immobilization of iron complexes on silica supports.
• Utilizing microporous molecular sieves as iron catalyst carriers.
• Anchoring iron catalysts onto resins and functionalized biopolymers.
• Employing Supported Ionic Liquid Phase (SILP) systems.
• Supporting Fe(III) ions on grafted chitosan.

Main Results:

• Silica-supported bis(arylimine)pyridyl iron complexes are effective for olefin polymerization.
• Microporous materials like MCM-41 and MCM-48 support iron catalysts for olefin polymerization and oxidation reactions.
• Anchored Fe(II)-anthranilic acid complexes catalyze urea reactions for carbamate synthesis.
• SILP systems enable chemoselective hydrogenation of aldehydes.
• Heterogeneous Fe(III) catalysts facilitate C-H bond activation.

Conclusions:

• Heterogenization strategies significantly enhance the applicability of iron catalysts.
• Diverse supports and methods enable tailored iron catalysts for polymerization, oxidation, hydrogenation, and C-H activation.
• Heterogeneous iron catalysis presents a promising avenue for sustainable chemical synthesis.