Controlling Electrical Conductance through a π‐Conjugated Cruciform Molecule by Selective Anchoring to Gold Electrodes

Abstract

Tuning charge transport at the single-molecule level plays a crucial role in the construction of molecular electronic devices. Introduced herein is a promising and operationally simple approach to tune two distinct charge-transport pathways through a cruciform molecule. Upon in situ cleavage of triisopropylsilyl groups, complete conversion from one junction type to another is achieved with a conductance increase by more than one order of magnitude, and it is consistent with predictions from ab initio transport calculations. Although molecules are well known to conduct through different orbitals (either HOMO or LUMO), the present study represents the first experimental realization of switching between HOMO- and LUMO-dominated transport within the same molecule.

Protonation tuning of quantum interference in azulene-type single-molecule junctions

“…Among those molecules exhibiting destructive quantum interference, azulene derivatives have also been considered as responsive molecular devices and materials, 11 – 13 because the five-seven ring system of azulene undergoes protonation in response to acid. 14 During protonation, the HOMO of the protonated azulene core with unpaired valence electrons is expected to move towards the Fermi level of the electrodes, which could create significant electrical conductance changes.…”

Donor‐/Acceptor‐Substituted Tetrakis(arylethynyl)benzenes: The Influence of Donor Group on Optoelectronic Properties

“…These molecules, along with the closely related 1,4‐bis(arylethenyl)‐2,5‐bis(arylethynyl)benzenes extensively studied by the Bunz group, are part of a larger family of ‘cruciform’ (X‐shaped) molecules . A notable property of many cruciform topologies is that quite often there is spatial separation of the highest density of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) onto different parts of the cross‐shaped structures, making these molecules well‐suited for applications such as non‐linear optical materials, charge transport at the single molecule level, and sensors for Lewis/Brønsted acids, metal ions and small molecules, to name a few examples.…”

Selective Nanomechanics of Aromatic versus Aliphatic Thiolates on Gold Surfaces

“…The interest in gold-based hybrid organic-inorganic interfacial materials has dramatically increased over the past decade due to their potential applications in diverse fields such as heterogeneous catalysis [1][2][3], molecular electronics [4][5][6][7][8], nanophotonics [9], as well as molecular biology and biomedicine [10][11][12][13][14][15]. Many of these applications involve the tailored modification of the metallic surface by incorporating molecules that provide new properties to the hybrid interface.…”