运动与热力学在金银表面的表面辅助乌尔曼合中的作用
Massimo Fritton1,2, David A Duncan1,3, Peter S Deimel1
1Department of Physics , Technical University of Munich , James-Franck-Strasse 1 , Garching 85748 , Germany.
Journal of the American Chemical Society
|March 1, 2019
概括
在Ag111) 和Au111) 表面上研究了表面辅助的Ullmann合. 脱化动力学不同,热力学在Au{111}上占主导地位,为纳米材料合成揭示了更长寿命的中间体.
科学领域:
- 表面化学
- 材料科学
- 纳米技术
背景情况:
- 表面辅助的乌尔曼合对于表面合成至关重要.
- 这种反应的基本机理方面尚未完全理解.
研究的目的:
- 在乌尔曼合中阐明单个反应步骤和取决于温度的进展.
- 在Ag111) 和Au111) 表面上比较1,3,5-tris(4-bromophenyl) 的合成.
主要方法:
- 温度编程的X射线光电子光谱 (TP-XPS) 用于监测脱和中间形成.
- 扫描道显微镜 (STM) 用于表征分子间键和网络拓.
- 密度函数理论 (DFT) 计算以确定反应度.
主要成果:
- 在第一阶级动力学下,在Ag{111}上脱是快速的,但在热力学控制下,在Au{111}上是渐进的.
- 在Au{111) 上的热力学得到了DFT计算的支持,显示了与实验数据的密切一致.
- 在对应合之前,在Au{111}上观察到表面稳定基的寿命更长.
结论:
- 这项研究揭示了Ullmann合的Ag{111) 和Au{111) 表面之间的明显热进展和机械差异.
- 了解这些差异,特别是Au的热力学控制,是合理设计原子精确纳米结构的关键.
- 获得的洞察力将有助于在表面上控制低维共价纳米材料的合成.
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