Molecular Lifting, Twisting, and Curling during Metal-Assisted Polycyclic Hydrocarbon Dehydrogenation

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• 作者：Davide Curcio ; Luca Omiciuolo ; Monica Pozzo ; Paolo Lacovig ; Silvano Lizzit ; Naila Jabeen ; Luca Petaccia ; Dario Alfè ; Alessandro Baraldi
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：March 16, 2016
• 年：2016
• 卷：138
• 期：10
• 页码：3395-3402
• 全文大小：526K
• ISSN：1520-5126

文摘

The atomistic understanding of the dissociation mechanisms for large molecules adsorbed on surfaces is still a challenge in heterogeneous catalysis. This is especially true for polycyclic aromatic hydrocarbons, which represent an important class of organic compounds used to produce novel graphene-based architectures. Here, we show that coronene molecules adsorbed on Ir(111) undergo major conformational changes during dissociation. They first tilt upward with respect to the surface, still keeping their planar configuration, and subsequently experience a rotation, which changes the molecular axis orientation. Upon lifting, the internal C–C strain is initially relieved; as the dehydrogenation proceeds, the molecules experience a progressive increase in the average interatomic distance and gradually settle to form dome-shaped nanographene flakes. Our results provide important insight into the complex mechanism of molecular breakup, which could have implications in the synthesis of new carbon-based nanostructured materials.