Selective Nanomechanics of Aromatic versus Aliphatic Thiolates on Gold Surfaces

ZOLOFF MICHOFF, MARTIN E.; RIBAS-ARINO, JORDI; MARX, DOMINIK

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

Año: 2019 vol. 122

0031-9007

Thiolated gold nanointerfaces play a key role in numerous fields of science, technology, as well asmodern medicine to coat, functionalize, and protect. Our computational study reveals that the mechanicalvs thermal stabilities of aliphatic thiolates on gold surfaces are strikingly different from those of aromaticthiolates. The aliphatic thiolates feature, at the same time, a higher thermal desorption energy but a lowermechanical rupture force than thiophenolates. Our analysis discloses that this most counterintuitiveproperty is due to different mechanochemical detachment mechanisms. Electronic structure analyses alongthe detachment pathways trace this back to the distinct electronic properties of the S─Au bond in stretchednanojunctions. The discoveries that it is a higher thermal stability that entails a lower mechanical stabilityand that mechanical loads generate different local nanostructures depending on the nature of the thiolate arehighly relevant for the rational design of improved thiol-gold nanocontacts.