Reversible Dehalogenation in On‐Surface Aryl–Aryl Coupling
Abstract
In the emerging field of on‐surface synthesis, dehalogenative aryl–aryl coupling is unarguably the most prominent tool for the fabrication of covalently bonded carbon‐based nanomaterials. Despite its importance, the reaction kinetics are still poorly understood. Here we present a comprehensive temperature‐programmed x‐ray photoelectron spectroscopy investigation of reaction kinetics and energetics in the prototypical on‐surface dehalogenative polymerization of 4,4′′‐dibromo‐p‐terphenyl into poly(para‐phenylene) on two coinage metal surfaces, Cu(111) and Au(111). We find clear evidence for reversible dehalogenation on Au(111), which is inhibited on Cu(111) owing to the formation of organometallic intermediates. The incorporation of reversible dehalogenation in the reaction rate equations leads to excellent agreement with experimental data and allows extracting the relevant energy barriers. Our findings deepen the mechanistic understanding and call for its reassessment for surface‐confined aryl–aryl coupling on the most frequently used metal substrates.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- May 28, 2020
- Source ID
- 10.1002/anie.202005443
Entities
People
- Amogh Kinikar
- Gabriela B. Barin
- José I Urgel
- Marco Di Giovannantonio
- Max Bommert
- Qiang Sun
- Roland Widmer
- Roman Fasel
- Samuel Stolz
Organizations
- Horizon 2020
- Office of Naval Research
- Swiss Federal Institute of Technology in Lausanne
- Swiss Federal Laboratories for Materials Science and Technology
- Swiss National Science Foundation
- University of Bern