Cu- and Pd-catalyzed Ullmann reaction on a hexagonal boron nitride layer

Area of Science:

• Surface science
• Organic chemistry
• Materials science

Background:

• The Ullmann reaction is a key C-C bond-forming reaction.
• On-surface synthesis offers unique control over molecular assembly.
• Hexagonal boron nitride (h-BN) is an emerging substrate for surface chemistry.

Purpose of the Study:

• To investigate the Ullmann reaction on h-BN/Ni(111).
• To explore the catalytic roles of copper (Cu) and palladium (Pd) atoms.
• To understand the influence of metal catalysts on reaction pathways.

Main Methods:

• Scanning tunneling microscopy (STM) for atomic-scale imaging.
• Dosing of molecular precursors and metal atoms onto h-BN.
• In situ analysis of reaction products and intermediates.

Main Results:

• Dispersed Cu and Pd atoms exhibit high catalytic activity for the Ullmann reaction.
• Both metals facilitate the reaction but lead to different product distributions.
• The h-BN substrate supports efficient metal atom catalysis.

Conclusions:

• Metal-catalyzed Ullmann reactions on h-BN are feasible.
• Catalyst choice (Cu vs. Pd) dictates reaction outcomes.
• This work advances on-surface organic synthesis strategies.