Insights in Reaction Mechanistics: Isotopic Exchange during the Metalation of Deuterated Tetraphenyl-21,23D-porphyrin on Cu(111)

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• 作者：Michael R枚ckert ; Matthias Franke ; Quratulain Tariq ; Dominik Lungerich ; Norbert Jux ; Michael Stark ; Andre Kaftan ; Stefanie Ditze ; Hubertus Marbach ; Mathias Laurin ; J枚rg Libuda ; Hans-Peter Steinr眉ck ; Ole Lytken
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：November 20, 2014
• 年：2014
• 卷：118
• 期：46
• 页码：26729-26736
• 全文大小：437K
• ISSN：1932-7455

文摘

Through the use of temperature-programmed desorption (TPD), the self-metalation and dehydrogenation of deuterated 5,10,15,20-tetraphenyl-21,23D-porphyrin on Cu(111) have been studied, resulting in new insight into the metalation of porphyrins on surfaces. The metalation is found to proceed through the transfer of the central aminic hydrogen atoms to the Cu(111) surface and not, as suggested by gas phase calculations, through the combination of the hydrogen atoms to molecular hydrogen above the partially inserted metal center. This finding suggests that the metalation reaction could be significantly influenced by the stability of hydrogen on the substrate surface. The metalation reaction and the subsequent hydrogenation and dehydrogenation of the periphery of the porphyrin molecule leading to hydrogen鈥揹euterium exchange are modeled with a simple microkinetic reaction model. The model is able to describe the main features of the TPD spectra.