Identifying the Conformational Isomers of Single-Molecule Cyclohexane at Room Temperature

Abstract

The identification of conformational isomers of the flexible molecule is challenging, owing to the rapid interconversion of isomers. By attaching two electrodes on a flexible molecule, cyclohexane, we accomplish the distinguishment of the two chair isomers of cyclohexane at room temperature using a single-molecule approach. The confinement effect of the attached electrodes not only plays an important role in identifying the chair isomers but also stabilizes the twist-boat intermediate that is showing a negligible distribution in the solution of cyclohexane.

A review of oligo(arylene ethynylene) derivatives in molecular junctions

“…225 The interconversion of conformational isomers of a cyclohexane ring in OAE3-like wires such as 40 has been detected in conductance measurements using the STM-BJ technique. 226 Fig. 21 Structures of molecular wires that incorporate a quinoidal unit into an OAE-like backbone.…”

The Evolution of the Charge Transport Mechanism in Single‐Molecule Break Junctions Revealed by Flicker Noise Analysis

“…[3] However, it remains exponent curve over the junction duration, we find that the charge transport mechanism of the single-molecule junctions typically transits from the through-space transport to the through-bond transport, and it is dominated by through-space transport again when the junction is about to rupture. This result gives an extension on the time dimension of previous studies, [21,22,24,25,29] in which the charge transport mechanism was determined from long-term junction durations that were achieved by forming single-molecule junctions between a static nanogap. In contrast to the case of a static molecule junction, frequency components of the single-molecule flicker noise in a dynamic break junction process exhibit clear time-dependent evolution behavior in the frequency range of ≈200-1000 Hz, as revealed by the TFA.…”

“…During the evolution of different junction configurations, the interface coupling may change dramatically with the evolution of electrode-molecule coupling during the break junction process, suggesting that an investigation of the time evolution of flicker noise in molecule junctions can provide a unique tool to understand the evolution of charge transport mechanisms. [24][25][26][27][28][29] However, the time dimension of the conductance traces is hardly deciphered in past studies. Toward the time resolution, time-frequency analysis (TFA) has proven to be an effective tool that combines both time and frequency dimensions in processing signals such as speech signals and polysomnography signals, [30,31] suggesting that TFA can be a promising approach to characterize the time evolution behavior of flicker noise in single-molecule junctions.In this study, we report that flicker noise can serve as an indicator of the evolution of charge transport mechanisms in single-molecule break junctions.…”

The Characterization of Electronic Noise in the Charge Transport through Single‐Molecule Junctions

“…We further identified the conformational isomers of single‐molecule cyclohexane at room temperature by power spectral density analysis. [ 65 ] As shown in the right panel of Figure 12f, the conformational isomers of cyclohexane‐based molecules could only be identified previously by nuclear magnetic resonance (NMR) characterization at low temperatures. However, with the increase of temperature, only one pattern of signals could be observed, revealing rapid interconversion of all conformational isomers.…”