Electric-Field-Driven Direct Desulfurization
| Autor: | Ulrike Kraft, Tomasz Michnowicz, Klaus Kern, Peter Wahl, Verena Schendel, Rémi Pétuya, Andrés Arnau, Bogdana Borca, Marcel Pristl, Uta Schlickum, Rico Gutzler, Hagen Klauk, Ivan Pentegov |
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| Přispěvatelé: | Ministerio de Economía y Competitividad (España), Eusko Jaurlaritza, German Research Foundation, University of St Andrews. School of Physics and Astronomy, University of St Andrews. Condensed Matter Physics |
| Předmět: |
Reaction mechanism
tetracenothiophene TK NDAS STM General Physics and Astronomy 02 engineering and technology 010402 general chemistry 01 natural sciences Chemical reaction DFT TK Electrical engineering. Electronics Nuclear engineering law.invention symbols.namesake Computational chemistry law Tunnel junction Electric field Single molecules QD General Materials Science Desulfurization Tetracenothiophene QC Chemistry Reaction step Fermi level General Engineering desulfurization QD Chemistry 021001 nanoscience & nanotechnology 0104 chemical sciences electric field QC Physics Chemical physics symbols Density functional theory single molecules Scanning tunneling microscope 0210 nano-technology |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| Popis: | The ability to elucidate the elementary steps of a chemical reaction at the atomic scale is important for the detailed understanding of the processes involved, which is key to uncover avenues for improved reaction paths. Here, we track the chemical pathway of an irreversible direct desulfurization reaction of tetracenothiophene adsorbed on the Cu(111) closed-packed surface at the submolecular level. Using the precise control of the tip position in a scanning tunneling microscope and the electric field applied across the tunnel junction, the two carbon-sulfur bonds of a thiophene unit are successively cleaved. Comparison of spatially mapped molecular states close to the Fermi level of the metallic substrate acquired at each reaction step with density functional theory calculations reveals the two elementary steps of this reaction mechanism. The first reaction step is activated by an electric field larger than 2 V nm, practically in absence of tunneling electrons, opening the thiophene ring and leading to a transient intermediate. Subsequently, at the same threshold electric field and with simultaneous injection of electrons into the molecule, the exergonic detachment of the sulfur atom is triggered. Thus, a stable molecule with a bifurcated end is obtained, which is covalently bound to the metallic surface. The sulfur atom is expelled from the vicinity of the molecule. We acknowledge funding by the Emmy-Noether-Program of the Deutsche Forschungsgemeinschaft and the SFB 767. R.P. and A.A. thank the Basque Departamento de Universidades e Investigacion (grant no. IT-756-13) and the Spanish Ministerio de Economía y Competitividad (grant nos. FIS2013-48286-C2- 8752-P and FIS2016-75862-P) for financial support. |
| Databáze: | OpenAIRE |
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