On-Surface Directional C-H Activation of Terminal Alkynes via Intermolecular Radical Transfer

Area of Science:

• Materials Science
• Surface Chemistry
• Nanotechnology

Background:

• On-surface synthesis of low-dimensional carbon nanomaterials like graphdiyne requires selective C(sp)-H bond activation in terminal alkynes.
• Existing methods using metal atoms, oxygen, or alkynyl halides face challenges in reaction selectivity and byproduct formation.

Purpose of the Study:

• To develop a directional C-H activation strategy for terminal alkynes on Ag(111) surfaces.
• To understand the reaction priority and selectivity governing intermolecular radical transfer between terminal alkynes.

Main Methods:

• Utilized scanning tunneling microscopy (STM) for in-situ observation of surface reactions.
• Employed density functional theory (DFT) calculations to investigate reaction mechanisms and energetics.
• Studied intermolecular radical transfer between different terminal alkynes on a silver (Ag(111)) surface.

Main Results:

• Demonstrated a directional C-H activation strategy via intermolecular radical transfer on Ag(111).
• Revealed that radical transfer is selective, occurring from molecules with higher radical populations to those with lower ones.
• Identified intrinsic molecular reactivity as the driving force for selective radical transfer.

Conclusions:

• Established a fundamental principle for controlling on-surface radical reactions.
• Provides a new pathway for the precise synthesis of diyne-based nanostructures.
• Offers insights into selective C-H activation for advanced carbon nanomaterial construction.