芳基
卤化
化学
X射线光电子能谱
偶联反应
聚合
金属
光化学
有机化学
催化作用
化学工程
聚合物
烷基
工程类
作者
Samuel Stolz,Marco Di Giovannantonio,José I. Urgel,Qiang Sun,Amogh Kinikar,Gabriela Borin Barin,Max Bommert,Román Fasel,Roland Widmer
标识
DOI:10.1002/anie.202005443
摘要
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.
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