C-C Coupling of Carbene Molecules on a Metal Surface in the Presence of Water.

Autor:	Cao Y; Ruhr-Universität Bochum, Lehrstuhl für Physikalische Chemie I, Universitätsstr. 150, Bochum D-44801, Germany., Mieres-Perez J; Technische Universität Dortmund, Lehrstuhl für Computational Bioengineering, Dortmund 44227, Germany., Lucht K; Ruhr-Universität Bochum, Lehrstuhl für Physikalische Chemie I, Universitätsstr. 150, Bochum D-44801, Germany., Ulrich I; Ruhr-Universität Bochum, Lehrstuhl für Organische Chemie II, Universitätsstr. 150, Bochum D-44801, Germany., Schweer P; Ruhr-Universität Bochum, Lehrstuhl für Physikalische Chemie I, Universitätsstr. 150, Bochum D-44801, Germany., Sanchez-Garcia E; Technische Universität Dortmund, Lehrstuhl für Computational Bioengineering, Dortmund 44227, Germany., Morgenstern K; Ruhr-Universität Bochum, Lehrstuhl für Physikalische Chemie I, Universitätsstr. 150, Bochum D-44801, Germany., Sander W; Ruhr-Universität Bochum, Lehrstuhl für Organische Chemie II, Universitätsstr. 150, Bochum D-44801, Germany.
Jazyk:	angličtina
Zdroj:	Journal of the American Chemical Society [J Am Chem Soc] 2023 May 31; Vol. 145 (21), pp. 11544-11552. Date of Electronic Publication: 2023 May 19.
DOI:	10.1021/jacs.2c12274
Abstrakt:	A novel surface-confined C-C coupling reaction involving two carbene molecules and a water molecule was studied by scanning tunneling microscopy in real space. Carbene fluorenylidene was generated from diazofluorene in the presence of water on a silver surface. While in the absence of water, fluorenylidene covalently binds to the surface to form a surface metal carbene, and water can effectively compete with the silver surface in reacting with the carbene. Water molecules in direct contact with fluorenylidene protonate the carbene to form the fluorenyl cation before the carbene can bind to the surface. In contrast, the surface metal carbene does not react with water. The fluorenyl cation is highly electrophilic and draws electrons from the metal surface to generate the fluorenyl radical which is mobile on the surface at cryogenic temperatures. The final step in this reaction sequence is the reaction of the radical with a remaining fluorenylidene molecule or with diazofluorene to produce the C-C coupling product. Both a water molecule and the metal surface are essential for the consecutive proton and electron transfer followed by C-C coupling. This C-C coupling reaction is unprecedented in solution chemistry.
Databáze:	MEDLINE
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