Atomic-scale insight into the formation, mobility and reaction of Ullmann coupling intermediates

Lewis, Emily A.; Murphy, Colin J.; Liriano, Melissa L.; Sykes, E. Charles H.

doi:10.1039/c3cc47002d

Cited by 52 publications

(69 citation statements)

References 35 publications

(40 reference statements)

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“…Similar adsorption of halogen atoms after dissociation from the molecule was observed previously. 29,[31][32]43 Moreover, as reported by Kuck et al 43 , the halogen atoms can promote molecular ordering on Cu(111). In 10] row (shown as second "green" carbon atom).…”

Section: Resultsmentioning

confidence: 81%

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From Graphene Nanoribbons on Cu(111) to Nanographene on Cu(110): Critical Role of Substrate Structure in the Bottom-Up Fabrication Strategy

et al. 2015

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Bottom-up strategies can be effectively implemented for the fabrication of atomically precise graphene nanoribbons. Recently, using 10,10'-dibromo-9,9'-bianthracene (DBBA) as a molecular precursor to grow armchair nanoribbons on Au(111) and Cu(111), we have shown that substrate activity considerably affects the dynamics of ribbon formation, nonetheless without significant modifications in the growth mechanism. In this paper we compare the on-surface reaction pathways for DBBA molecules on Cu(111) and Cu(110). Evolution of both systems has been studied via a combination of core-level X-ray spectroscopies, scanning tunneling microscopy, and theoretical calculations. Experimental and theoretical results reveal a significant increase in reactivity for the open and anisotropic Cu(110) surface in comparison with the close-packed Cu(111). This increased reactivity results in a predominance of the molecular-substrate interaction over the intermolecular one, which has a critical impact on the transformations of DBBA on Cu(110). Unlike DBBA on Cu(111), the Ullmann coupling cannot be realized for DBBA/Cu(110) and the growth of nanoribbons via this mechanism is blocked. Instead, annealing of DBBA on Cu(110) at 250 °C results in the formation of a new structure: quasi-zero-dimensional flat nanographenes. Each nanographene unit has dehydrogenated zigzag edges bonded to the underlying Cu rows and oriented with the hydrogen-terminated armchair edge parallel to the [1-10] direction. Strong bonding of nanographene to the substrate manifests itself in a high adsorption energy of -12.7 eV and significant charge transfer of 3.46e from the copper surface. Nanographene units coordinated with bromine adatoms are able to arrange in highly regular arrays potentially suitable for nanotemplating.

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Section: Resultsmentioning

confidence: 81%

“…Particularly, Ullmann-type reactions were successfully utilized for the synthesis of 1D 28-31 and 2D 28,30,[32][33][34][35][36][37][38][39] polymer nanostructures from suitable precursor molecules on noble metal surfaces.…”

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confidence: 99%

From Graphene Nanoribbons on Cu(111) to Nanographene on Cu(110): Critical Role of Substrate Structure in the Bottom-Up Fabrication Strategy

et al. 2015

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“…[18][19][20][21] To date,t wo types of surface intermediates have been identified, [14] depending on how the aromatic species are bonded to surface metal atoms:1 )free-standing organometallic intermediates [22][23][24][25] and 2) surface-anchored aromatic species. TheUllmann coupling reaction is of great significance in constructing surface covalent nanostructures using halogen-containing aromatic derivatives.…”

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confidence: 99%

Steering Surface Reaction Dynamics with a Self‐Assembly Strategy: Ullmann Coupling on Metal Surfaces

et al. 2017

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Ullmann coupling of 4-bromobiphenyl thermally catalyzed on Ag(111), Cu(111), and Cu(100) surfaces was scrutinized by scanning tunneling microscopy as well as theoretical calculations. Detailed experimental evidence showed that initial formation of organometallic intermediates on the surface, as self-assembled structures or sparsely dispersed species, is determined by the subsequent reaction pathway. Specifically, the assembled organometallic intermediates at full coverage underwent a single-barrier process to directly convert into the final coupling products, while the sparsely dispersed intermediates at low coverage went through a double-barrier process via newly identified clover-shaped intermediates prior to formation of the final coupling products. These findings demonstrate that a self-assembly strategy can efficiently steer surface reaction pathways and dynamics.

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“…[38] In these studies, rigid component molecules were usually employed to build polymers of different dimensions, whereas increasing attention has been given to the adsorption and on-surface synthesis of much larger and more flexible species. [39][40][41][42] The Schiff base reaction has been widely applied in dynamic covalent chemistry, [43,44] and it has also been investigated both under UHV and ambient conditions by means of scanning tunneling microscopy (STM). [23][24][25][32][33][34][35] The reactions, particularly those that result in small-molecule imine compounds, can proceed under room temperature, [32,43] whereas for the preparation of high-quality surface 2D polymers, mild heating is normally necessary.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of One‐Dimensional Schiff Base Polymers that Contain an Oligothiophene Building Block on the Graphite Surface

Sun

Fan

Yang

et al. 2015

Chemistry A European J

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Surface-mediated Schiff base coupling reactions between oligothiophenes equipped with an aldehyde group and aromatic diamines were investigated on highly oriented pyrolytic graphite (HOPG) by means of scanning tunneling microscopy (STM) under ambient conditions. To investigate the evolution process from monomers to resultant polymers and the mechanism of reactions, we controlled the ratio of precursors and the reactive temperature, and we obtained high-resolution STM images of different stages of the surface reaction. The results suggest that preferential adsorption of one kind of monomer has a great influence on the on-surface Schiff base reaction.

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Atomic-scale insight into the formation, mobility and reaction of Ullmann coupling intermediates

Abstract: The Ullmann reaction of bromobenzene, the simplest coupling reagent, to form biphenyl on a Cu surface proceeds via a highly mobile organometallic intermediate in which two phenyl groups extract and bind a single surface Cu atom.

Cited by 52 publications

References 35 publications

From Graphene Nanoribbons on Cu(111) to Nanographene on Cu(110): Critical Role of Substrate Structure in the Bottom-Up Fabrication Strategy

From Graphene Nanoribbons on Cu(111) to Nanographene on Cu(110): Critical Role of Substrate Structure in the Bottom-Up Fabrication Strategy

Steering Surface Reaction Dynamics with a Self‐Assembly Strategy: Ullmann Coupling on Metal Surfaces

Synthesis of One‐Dimensional Schiff Base Polymers that Contain an Oligothiophene Building Block on the Graphite Surface

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