Surface-induced symmetry reduction in molecular switching: asymmetric cis–trans switching of CH₃S-Au-SCH₃on Au(111)

Abstract

The cis-trans isomerization of CHS-Au-SCH driven by the tip of the scanning tunneling microscope is investigated at 77 K. CHS-Au-SCH anchored on the Au(111) surface with the S-Au-S axis parallel to the substrate functions as a molecular switch due to the flipping of the CH groups. The bonding between CHS-Au-SCH and Au(111) leads to asymmetric isomerization where one of the two methyl groups flips much more effectively than the other, despite the symmetry of CHS-Au-SCH. Our findings suggest the possibility of constructing similar molecular switches that can be operated at room temperature and a potential route for fine-tuning of molecular switches in future nanoscale electro-mechanical devices.

Supramolecular Networks and Wires Dominated by Intermolecular BiEDOT Interactions

“…32−41 Methylthiolate self-assembly and isomerization on a Au(111) surface and the direct observation of photoinduced tautomerization in single porphycene molecules on a Cu(111) surface were also recently reported. 42,43 Linear molecules can form densely close-packed or flower-like structures with cavities depending on the intermolecular interactions. 25,31,44,45 Triangle-shaped molecules with different substituents form open honeycomb or flower-like structures 46−48 or close-packed stripe-like structures.…”

Molecular Isomerization and Multiscale Phase Transitions of a Ditopic Ligand on a Surface

“…The cis−trans isomerization of CH 3 S−Au− SCH 3 involves a two-dimensional (2D) chirality switching between enantiomers. 26 Other molecular systems exhibit switchable behavior on surfaces. For example, the direct observation of photoinduced tautomerization in single porphycene molecules on a Cu(111) surface was recently reported.…”

“…This isomerization can be induced by irradiation, , heating, or the application of an electric field on various surfaces. − Methylthiolate self-assembly and isomerization on a Au(111) surface is another system recently studied by STM. The cis – trans isomerization of CH 3 S–Au–SCH 3 involves a two-dimensional (2D) chirality switching between enantiomers . Other molecular systems exhibit switchable behavior on surfaces.…”

Spontaneous Breaking and Remaking of the RS–Au–SR Staple in Self-assembled Ethylthiolate/Au(111) Interface

“…However, the change in the distance observed here is too large for conformational variations. Moreover, conformational changes are observed only under very low bias voltage . The relatively large displacement exhibited by the α branch can only be explained by a true physical translation of this branch.…”

“…Moreover, conformational changes are observed only under very low bias voltage. 59 The relatively large displacement exhibited by the α branch can only be explained by a true physical translation of this branch. There is the possibility that the C 2 S−Au−SC 2 staple breaks apart according to the following scheme.…”