Hexagons to Ribbons: Flipping Cyanide on Au{111}

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• 作者：Andrew I. Guttentag ; Kristopher K. Barr ; Tze-Bin Song ; Kevin V. Bui ; Jacob N. Fauman ; Leticia F. Torres ; David D. Kes ; Adina Ciomaga ; Jérôme Gilles ; Nichole F. Sullivan ; Yang Yang ; David L. Allara ; Michael Zharnikov ; Paul S. Weiss
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：December 7, 2016
• 年：2016
• 卷：138
• 期：48
• 页码：15580-15586
• 全文大小：572K
• ISSN：1520-5126

文摘

Cyanide monolayers on Au{111} restructure from a hexagonal close-packed lattice to a mixed-orientation “ribbon” structure through thermal annealing. The new surface structure loses most of the observed surface features characterizing the initial as-adsorbed system with “ribbon” domain boundaries isolating rotationally offset surface regions where the orientation is guided by the underlying gold lattice. A blue shift to higher frequencies of the CN vibration to 2235 cm^–1 with respect to the as-adsorbed CN/Au{111} vibration at 2146 cm^–1 is observed. In addition, a new low-frequency mode is observed at 145 cm^–1, suggesting a chemical environment change similar to gold–cyanide crystallization. We discuss this new structure with respect to a mixed cyanide/isocyanide monolayer and propose a bonding scheme consisting of Au-CN and Au-NC bound molecules that are oriented normal to the Au{111} surface.