Mechanistic insights into on-surface reactions from isothermal temperature-programmed X-ray photoelectron spectroscopy

Grossmann, Lukas; Hocke, Manuela; Galeotti, Gianluca; Contini, Giorgio; Floreano, Luca; Cossaro, Albano; Ghosh, Amit; Schmittel, Michael; Rosen, Johanna; Heckl, Wolfgang M.; Björk, Jonas; Lackinger, Markus

doi:10.1039/d4nr00468j

Cited by 3 publications

(1 citation statement)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We also highlight a recent TP-XPS study on debromination of aromatic compounds on metal surfaces, where the samples were prepared with a stepped temperature profile comprised of isothermal segments. It helps reduce fitting ambiguities in the commonly applied annealing condition of linear temperature ramps . The current work not only enhances our understanding of dehalogenation reactions but also underscores the critical role of the kinetic effect in on-surface reactions.…”

Section: Discussionmentioning

confidence: 99%

Kinetics of On-Surface Dechlorinated Aryl–Aryl Coupling

He,

Jiang,

Zhu

et al. 2024

J. Phys. Chem. C

View full text Add to dashboard Cite

Dehalogenative aryl−aryl coupling has been the key strategy in on-surface synthesis for crafting covalently bonded carbon-based nanomaterials. However, comprehensive studies focusing on the kinetics of these reactions are notably rare. Moreover, the existing literature predominantly addresses debromination, often neglecting dechlorination, a critical reaction requiring higher energies but with profound implications for environmental protection and advancement of sustainable chemistry practices. Here, we combined synchrotron-based X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM) to study the dehalogenated coupling reactions of chlorinated and brominated aromatic hydrocarbons on the Au(111) surface. The high-resolution surface-sensitive techniques allow to identify the reactants and products. We find that extended annealing facilitates setting the activation temperature for dechlorinated coupling to around 473 K, a notable decrease from the previously considered 573 K, highlighting the significant impact of kinetic effects on the on-surface reaction process. Using the temperature-programmed XPS measurement, we are able to extract the kinetic curves of the dechlorinated coupling reactions and obtain detailed insight into the reaction process. This research enhances our mechanistic understanding of the widely utilized on-surface dehalogenative coupling reaction, serving as a fundamental step toward optimizing its efficiency and selectivity.

show abstract

Section: Discussionmentioning

confidence: 99%

Kinetics of On-Surface Dechlorinated Aryl–Aryl Coupling

He,

Jiang,

Zhu

et al. 2024

J. Phys. Chem. C

View full text Add to dashboard Cite

show abstract

A Density Functional Benchmark for Dehydrogenation and Dehalogenation Reactions on Coinage Metal Surfaces

Chen,

Rosen,

Björk

2024

ChemPhysChem

View full text Add to dashboard Cite

The on‐surface synthesis of low‐dimensional organic nanostructures has been extensively investigated through both experimental and theoretical methods, particularly by density functional theory (DFT). However, the complex mixture of interactions often poses challenges within the DFT framework, and there is a knowledge‐gap regarding how the choice of DFT approach affects the computed results. Here, five different approaches including vdW interactions, i.e., PBE+D3, PBE+vdWsurf, rev‐vdW‐DF2, r2SCAN+rVV10 and BEEF‐vdW, are employed to describe three prototypical on‐surface reactions; dehydrogenation of benzene, debromination of bromobenzene, and deiodination of iodobenzene on the (111) facets of the coinage metals. Overall, rev‐vdW‐DF2 outperforms the other methods in describing benzene adsorption, whereas BEEF‐vdW falls short. For dehydrogenation and debromination on Cu(111), all functionals except BEEF‐vdW give reasonable activation energies compared to experiments. A similar trend is observed for Ag(111) and Au(111), with BEEF‐vdW yielding significantly higher activation and reaction energies. For dehalogenation, all the five vdW approaches correctly capture the reactivity trend – Cu(111) > Ag(111) > Au(111) – and the expected hierarchy between bromobenzene desorption and carbon‐ bromine activation. Only BEEF‐vdW fails to predict the faster kinetics of deiodination than the iodobenzene desorption. Our work forms a basis for evaluating density functionals in describing chemical reactions on surfaces.

show abstract

Real-Time Imaging of On-Surface Ullmann Polymerization Reveals an Inhibiting Effect of Adatoms

Dettmann,

Panighel,

Preetha Genesh

et al. 2024

J. Am. Chem. Soc.

View full text Add to dashboard Cite

Ullmann coupling is a widely used reaction for the on-surface growth of low-dimensional carbon nanomaterials. The irreversible nature of this reaction prevents the "self-healing" of defects, and a detailed knowledge of its mechanism is therefore essential to enable the growth of extended ordered structures. However, the dynamics of the Ullmann polymerization remain largely unexplored, as coupling events occur on a timescale faster than conventional scanning probe microscopy imaging frequencies. Here, we reveal the dynamics of these surface events using highspeed variable-temperature scanning tunneling microscopy (STM) (10 frames per second). Performing the measurements at the onset reaction temperatures provides an unprecedented description of the evolution of organometallic (OM) and covalent surface species during the Ullmann polymerization of para-dibromobenzene on Cu(110). Our results demonstrate the existence of an intermediate OM phase with Cu adatoms that inhibits the polymerization. These observations now complete the picture of the pathways of on-surface Ullmann polymerization, which includes the complex interplay of the phenylene moieties and metal atoms. Our work demonstrates the unique capability of high-speed STM to capture the dynamics of molecular self-assembly and coupling.

show abstract

Mechanistic insights into on-surface reactions from isothermal temperature-programmed X-ray photoelectron spectroscopy

Abstract: On-surface synthesis often proceeds under kinetic control due to the irreversibility of key reaction steps, rendering kinetic studies pivotal. The accurate quantification of reaction rates also bears potential for unveiling...

Cited by 3 publications

References 64 publications

Kinetics of On-Surface Dechlorinated Aryl–Aryl Coupling

Kinetics of On-Surface Dechlorinated Aryl–Aryl Coupling

A Density Functional Benchmark for Dehydrogenation and Dehalogenation Reactions on Coinage Metal Surfaces

Real-Time Imaging of On-Surface Ullmann Polymerization Reveals an Inhibiting Effect of Adatoms

Contact Info

Product

Resources

About