Efficiency of π−π Tunneling in [2]Rotaxane Molecular Electronic Switches

Abstract

We perform large-scale density functional and matrix Green's function calculations, and study the coherent charge tunneling properties of molecular electronic devices based on the central part of [2]rotaxane molecules. We extract molecular core regions from realistic monolayer configurations with folded molecular structures and sandwich them between Au(111) electrodes to form device models. We show that the electrical switching behavior can be observed within the π-π stacked serial arrangement of redox-active components in the [2]rotaxane monolayer as with the parallel arrangement in the [2]catenane case. We thus demonstrate the effectiveness of the π-π electron tunneling and the universality of the switching mechanism based on the energetic movement of frontier orbitals accompanying the conformational switching. In addition, via considering the energetic ordering of highest-occupied molecular orbital (HOMO) and HOMO-1 levels that originated from tetrathiafulvalene and dioxynaphthalene in several ground-state conformation device models, we show that the molecule-electrode configurations critically affect the device functionality.

Enantioselective Limiting Transport into a Fixed Cavity via Supramolecular Interaction for the Chiral Electroanalysis of Amino Acids Regardless of Electroactive Units

“…The ferrocenyl group shifts from 4.15 to 4.28 ppm (Δδ = 0.13 ppm). All of these changes are ascribed to the multiple molecular interactions occurring in close proximity, including π–π stacking between the phenyl and ferrocenyl groups and the C–H···π effect that occurs when the ferrocenyl group and dipyridinium cation are alongside each other. − Consequently, we envision the possible chemical structure of the 1:1 mixture in Figure .…”

Free Energy Barrier for Molecular Motions in Bistable [2]Rotaxane Molecular Electronic Devices

“…The purpose of this paper is to provide such validation. Previously, we investigated these compounds using a multiscale first principles approach combining quantum mechanics (QM) and atomistic force field (FF) methods. − First we considered the molecules as individual species, and then we examined self-assembled monolayers bound to gold surfaces or compressed into Langmuir monolayers at the air−water interface. These studies successfully predicted a number of phenomena that were confirmed later experimentally, including the higher conductivity of the DNP relative to the TTF, and the increased stability of the TTF relative to the DNP (by 2.0 kcal/mol from QM, 2.3 kcal/mol from the FF, and 1.4−1.6 kcal/mol from experiment). , In addition, on the basis of the predicted footprint of the 115 Å 2 /molecule for the self-assembled structure, we predicted that the surface tension of the TTF is 32% lower than that of the DNP, an observation that was confirmed in subsequent experiements. , …”

“…Previously, we investigated these compounds using a multiscale first principles approach combining quantum mechanics (QM) and atomistic force field (FF) methods. − First we considered the molecules as individual species, and then we examined self-assembled monolayers bound to gold surfaces or compressed into Langmuir monolayers at the air−water interface. These studies successfully predicted a number of phenomena that were confirmed later experimentally, including the higher conductivity of the DNP relative to the TTF, and the increased stability of the TTF relative to the DNP (by 2.0 kcal/mol from QM, 2.3 kcal/mol from the FF, and 1.4−1.6 kcal/mol from experiment). , In addition, on the basis of the predicted footprint of the 115 Å 2 /molecule for the self-assembled structure, we predicted that the surface tension of the TTF is 32% lower than that of the DNP, an observation that was confirmed in subsequent experiements. , …”

Influence of ring position on the temporal dependence of charge movement in a switchable [2]rotaxane

“…In this work, the transport properties of an isolated Stoddart‐Heath‐type rotaxane in these two coconformations of its neutral state were explored. The transport properties of rotaxane molecular junctions are also known to be influenced by the molecule‐electrode interface . This dependence of the transport properties on the rotaxane/electrode interface is presumably relatively independent of coconformation and is not included in this work.…”