Molecular-Scale Visualization of Steric Effects of Ligand Binding to Reconstructed Au(111) Surfaces

TL;DR

This study uses advanced microscopy and spectroscopy to visualize how individual ligands bind to a gold surface, revealing how surface features influence binding and molecular properties at the single-molecule level.

Contribution

It provides the first direct visualization and analysis of site-dependent steric effects on ligand binding to reconstructed Au(111) surfaces using combined experimental and theoretical methods.

Findings

Surface features influence ligand vibrational signatures.

Steric pressure affects binding site selectivity.

Molecular-level insights into ligand-surface interactions.

Abstract

Direct imaging of single molecules at nanostructured interfaces is a grand challenge, with potential to enable new, precise material architectures and technologies. Of particular interest are the structural morphology and spectroscopic signatures of the adsorbed molecule, where modern probes are only now being developed with the necessary spatial and energetic resolution to provide detailed information at molecule-surface interface. Here, we directly visualize the binding of individual m-terphenyl isocyanide ligands to a reconstructed Au(111) surface through scanning tunneling microscopy (STM) and inelastic electron tunneling spectroscopy (IETS). The site-dependent steric pressure of the various surface features alters the vibrational fingerprints of the m-terphenyl isocyanides, which is characterized with single-molecule precision through joint experimental and theoretical approaches. This study for the first time provides molecular-level insights into the steric-pressure-enabled surface binding selectivity, as well as its effect on the chemical properties of individual surface-binding ligands.