title: Single-molecule insight into Wurtz reactions on metal surfaces.
abstract: Wurtz reactions feature the dehalogenated coupling of alkyl halides. In comparison to their widely investigated counterparts, Ullmann reactions, Wurtz reactions have however been scarcely explored on surfaces. Herein, by combining high-resolution STM imaging and DFT calculations, we have systematically investigated Wurtz reactions on three chemically different metal surfaces including Cu(110), Ag(110) and Au(111). We find that the Wurtz reactions could be achieved on all three surfaces, and the temperatures for triggering the reactions are in the order of Cu(110) > Ag(110) > Au(111). Moreover, DFT calculations have been performed to unravel the pathways of on-surface Wurtz reactions and identify three basic steps of the reactions including debromination, diffusion and coupling processes. Interestingly, we found that the mechanism of the on-surface Wurtz reaction is intrinsically different from the Ullmann reaction and it is revealed that the coupling process is the rate-limiting step of Wurtz reactions on three different substrates. These findings have given a comprehensive picture of Wurtz reactions on metal surfaces and demonstrated that such a reaction could be an alternative reaction scheme for advanced on-surface synthesis.
authors.affiliation: Tongji-Aarhus Joint Research Center for Nanostructures and Functional Nanomaterials, College of Materials Science and Engineering, Tongji University, Caoan Road 4800, Shanghai 201804, P. R. China. xuwei@tongji.edu.cn.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Sun
authors.affiliation: Tongji-Aarhus Joint Research Center for Nanostructures and Functional Nanomaterials, College of Materials Science and Engineering, Tongji University, Caoan Road 4800, Shanghai 201804, P. R. China. xuwei@tongji.edu.cn.
authors.forename: Liangliang
authors.initials: L
authors.lastname: Cai
authors.affiliation: Tongji-Aarhus Joint Research Center for Nanostructures and Functional Nanomaterials, College of Materials Science and Engineering, Tongji University, Caoan Road 4800, Shanghai 201804, P. R. China. xuwei@tongji.edu.cn.
authors.forename: Yuanqi
authors.initials: Y
authors.lastname: Ding
authors.affiliation: Tongji-Aarhus Joint Research Center for Nanostructures and Functional Nanomaterials, College of Materials Science and Engineering, Tongji University, Caoan Road 4800, Shanghai 201804, P. R. China. xuwei@tongji.edu.cn.
authors.forename: Honghong
authors.initials: H
authors.lastname: Ma
authors.affiliation: Tongji-Aarhus Joint Research Center for Nanostructures and Functional Nanomaterials, College of Materials Science and Engineering, Tongji University, Caoan Road 4800, Shanghai 201804, P. R. China. xuwei@tongji.edu.cn.
authors.forename: Chunxue
authors.initials: C
authors.lastname: Yuan
authors.affiliation: Tongji-Aarhus Joint Research Center for Nanostructures and Functional Nanomaterials, College of Materials Science and Engineering, Tongji University, Caoan Road 4800, Shanghai 201804, P. R. China. xuwei@tongji.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Xu