Formation of Methyl Isocyanide from Dimethylamine on Pt(111)
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- 作者：Kumudu Mudiyanselage ; Michael Trenary ; Randall J. Meyer
- 刊名：Journal of Physical Chemistry C
- 出版年：2008
- 出版时间：March 13, 2008
- 年：2008
- 卷：112
- 期：10
- 页码：3794 - 3799
- 全文大小：145K
- 年卷期：v.112,no.10(March 13, 2008)
- ISSN：1932-7455
文摘
The conversion of dimethylamine ((CH3)2NH) to methyl isocyanide (CNMe) through a methylaminocarbyne(CNHMe) intermediate on Pt(111) has been studied experimentally with reflection absorption infraredspectroscopy (RAIRS) and theoretically with density functional theory (DFT). (CH3)2NH adsorbs molecularlyat 85 K through the nitrogen lone pair and dehydrogenates to produce CNHMe at 350 K. Both experimentalobservations and the results of DFT calculations show that CNHMe is more stable on the surface than either(CH3)2NH or CNMe. However, surface CNHMe can be converted to the less stable CNMe via two differentpathways. A small amount of CNMe is formed at temperatures above 350 K due to the dehydrogenation ofCNHMe accompanied by desorption of H2, which drives the reaction forward. The second pathway involvesthe reaction at 85 K with water adsorbed from the background, which leads to a complete conversion ofCNHMe to form both on-top and bent-bridge-bonded CNMe. It is assumed that the dehydrogenation of theCNHMe molecules produces hydrated hydronium ions of the general formula ((H2O)nH3O)+, although directspectroscopic evidence for such species was not obtained.