# Electronic Coupling of Molecular Complexes to Au Electrodes Mediated via Host–Guest Interactions

## TL;DR

This paper explores how molecular complexes can be electronically coupled to gold electrodes using host-guest interactions, enabling long-range coupling despite a large distance.

## Contribution

The study demonstrates long-range electronic coupling mediated by host-guest interactions, which is novel for molecular complexes on gold electrodes.

## Key findings

- Host-bound guests show substantial electronic coupling to the Au surface despite being ∼1.3 nm away.
- Surface-enhanced infrared absorption spectroscopy confirms distinct spectral features of host-bound species.
- Density functional theory calculations highlight the host's role in mediating long-range coupling.

## Abstract

Immobilization of
molecular catalysts onto electrode surfaces using
host–guest (HG) interactions enables the facile regeneration
of electrodes following catalyst degradation. Beyond this practical
aspect, the architecture also offers a unique way to study the electronic
coupling of molecules to the electrode through a nominally insulating
linker. Here, we employ surface-enhanced infrared absorption spectroscopy
(SEIRAS) to characterize the binding and electronic coupling of Au-bound
HG complexes. Distinct spectral features and binding kinetics differentiate
host-bound species from physisorbed analogues, confirming well-defined
HG assemblies on the surface. Analysis of the wavenumber shifts of
the guest as a function of applied potential suggests that while the
coupling of physisorbed guests with the surface is not strong, the
host-bound guests show a substantial electronic coupling considering
their distance from the surface of ∼1.3 nm. Density functional
theory calculations reveal the key role of the host in mediating this
long-range coupling between the Au surface and the guest.