Single-Molecule Vibrational Characterization of Binding Geometry Effects on Isocyanide-Metal Interactions
Abstract
Isocyanide-metal binding is governed by sigma-donation and pi-back-bonding, which affects the energy of the isocyanide stretching mode-a characteristic probe for ligand-metal interactions. While extensive correlations exist between structure and spectroscopy in molecular isocyanide-metal systems, isocyanide interactions with metallic crystalline surfaces, where ligands often bind in various geometries, remain poorly understood. Conventional vibrational spectroscopies, such as infrared and Raman, lack the molecular-scale resolution needed to distinguish these inhomogeneous configurations. In contrast, inelastic electron tunneling spectroscopy with scanning tunneling microscopy (STM-IETS) enables direct visualization of ligand adsorption geometries and their vibrational signatures. Using STM-IETS, here we investigate a matal-adsorbed m-terphenyl isocyanie ligand and find that adsorption geometry on Cu(100) induces a significant shift in isocyanide stretching frequency, even greater than replacing Cu(100) with Ag(111). Density functional theory confirms this shift arises from atomic-scale variations in isocyanide-metal binding. This study elucidates how atomic-scale binding influences the vibrational signatures of isocyanide ligands-an often-overlooked factor in understanding isocyanide-metal interactions.
Cite
@article{arxiv.2504.03945,
title = {Single-Molecule Vibrational Characterization of Binding Geometry Effects on Isocyanide-Metal Interactions},
author = {Liya Bi and Zhe Wang and Krista Balto and Andrea R. Tao and Tod A. Pascal and Yanning Zhang and Joshua S. Figueroa and Shaowei Li},
journal= {arXiv preprint arXiv:2504.03945},
year = {2025}
}