Interfacial electric fields catalyze Ullmann coupling reactions on gold surfaces

13 July 2022, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


The electric fields created at solid-liquid interfaces are important in heterogeneous catalysis. Here we describe the Ullmann coupling of aryl iodides on rough gold surfaces, which we monitor in situ using the scanning tunneling microscope-based break junction (STM-BJ) and ex situ using mass spectrometry and fluorescence spectroscopy. We find that this Ullman coupling reaction occurs only on rough gold surfaces in polar solvents, the latter of which implicates interfacial electric fields. These experimental observations are supported by density functional theory calculations that elucidate the roles of surface roughness and local electric fields on the reaction. More broadly, this touchstone study offers a facile method to access and probe in real time an increasingly prominent yet incompletely understood mode of catalysis.


Ullmann Coupling
Electric Field Chemistry
Interfacial Fields
Scanning Tunneling Microscope

Supplementary materials

Supporting Information
Synthetic methods and additional data


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