Fe(III)-Based Phenylsilsesquioxane/Acetylacetonate Complexes: Synthesis, Cage-like Structure, and High Catalytic...

Area of Science:

• Coordination Chemistry
• Organometallic Chemistry
• Catalysis

Background:

• Silsesquioxanes are versatile silicon-oxygen cage compounds with tunable properties.
• Metal-organic complexes are crucial in catalysis due to their unique reactivity.
• Developing efficient catalysts for inert alkane oxidation and CO2 utilization is a significant challenge.

Purpose of the Study:

• To synthesize novel iron-based silsesquioxane/acetylacetonate complexes.
• To investigate the structure-property relationships of these complexes.
• To evaluate their catalytic performance in alkane oxidation and CO2 cycloaddition reactions.

Main Methods:

• Synthesis of iron-based silsesquioxane/acetylacetonate complexes.
• Structural characterization using spectroscopic and crystallographic techniques.
• Catalytic activity assessment in alkane oxidation with peroxides and CO2 cycloaddition with epoxides.

Main Results:

• Successfully synthesized unprecedented iron-based silsesquioxane/acetylacetonate complexes with alkaline metal-dependent cage structures (Fe2Li2, Fe4Na4, Fe3K3).
• Reported the first observation of trimeric silsesquioxane ligands in cage-like metallasilsesquioxanes (Fe3K3 complex).
• The Fe4Na4 complex demonstrated record high activity in cyclohexane oxidation (55% yield of oxygenates) and efficient catalysis for CO2 cycloaddition with epoxides (58-96% yields).

Conclusions:

• The synthesized iron complexes exhibit unique alkaline metal-dependent structures.
• These complexes serve as highly effective catalysts for challenging chemical transformations.
• The findings open new avenues for designing advanced catalysts based on metallasilsesquioxanes.