Protected but accessible: oxygen activation by a calixarene-stabilized undecagold cluster

Area of Science:

• Computational chemistry
• Catalysis
• Nanomaterials

Background:

• Subnanometer metal clusters are promising catalysts but often lack stability.
• Enzymatic metal centers provide inspiration for designing artificial catalysts.

Purpose of the Study:

• To investigate the stabilization of subnanometer gold clusters using calixarenes.
• To explore the catalytic potential of these stabilized gold clusters for oxidation reactions.

Main Methods:

• Density Functional Theory (DFT) computations were employed.
• The interaction between calixarene hosts and Au11 clusters was analyzed.
• Dioxygen binding and activation on the gold cluster were studied.

Main Results:

• Calixarenes effectively stabilize the subnanometer Au11 clusters.
• The stabilized clusters allow small molecules like O2 access to reactive sites.
• Up to three dioxygen molecules can bind and are activated to a superoxo state.
• DFT calculations confirm the potential for ambient condition catalysis.

Conclusions:

• Calixarene-stabilized gold clusters show promise as oxidation catalysts.
• The mechanism of O2 activation is elucidated.
• This work provides a pathway for designing enzyme-mimicking gold catalysts.