A water-soluble Pd₆ coordination cage via multicomponent assembly for visible-light-driven oxidation

Area of Science:

• Supramolecular Chemistry
• Organometallic Chemistry
• Photocatalysis

Background:

• Multicomponent self-assembly is a powerful strategy for constructing complex molecular architectures.
• Selective oxidation of C-H bonds remains a significant challenge in synthetic chemistry.
• Developing efficient and recyclable photocatalysts is crucial for sustainable chemical synthesis.

Purpose of the Study:

• To synthesize a water-soluble palladium (Pd) cage with a photoactive ligand.
• To investigate the cage's ability to selectively oxidize alkyl aromatics under white-light irradiation.
• To demonstrate the catalyst's recyclability and application in aqueous media.

Main Methods:

• Multicomponent self-assembly was employed to create the Pd6 cage.
• The cage's photocatalytic activity was tested using various alkyl aromatics under white light.
• Product analysis was performed using standard spectroscopic techniques.
• Recyclability studies were conducted over multiple reaction cycles.

Main Results:

• A water-soluble Pd6 cage functionalized with a photoactive ligand was successfully synthesized.
• The cage demonstrated high selectivity in oxidizing secondary and tertiary C-H bonds adjacent to aromatic rings.
• Specific oxidation of cumene to acetophenone and p-cymene to 4-methylacetophenone was achieved in water.
• The photocatalyst exhibited excellent recyclability, maintaining its activity over several cycles.

Conclusions:

• The developed Pd6 cage is an effective and recyclable photocatalyst for selective oxidation reactions in water.
• Cavity-controlled selectivity enables precise functionalization of alkyl aromatics.
• This work offers a promising approach for sustainable synthesis of aromatic compounds.