Related Experiment Video
Updated: Aug 29, 2025

Single-Molecule Förster Resonance Energy Transfer Methods for Real-Time Investigation of the Holliday Junction Resolution by GEN1
Published on: September 18, 2019
Hydrogen-bond-induced quantum interference in single-molecule junctions of regioisomers
Lingbing Ge1, Songjun Hou2, Yaorong Chen3
1School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China (UESTC) Chengdu 610054 People's Republic of China zhengyonghao@uestc.edu.cn xdliu@uestc.edu.cn.
Protic solvents can tune single-molecule junction conductance by controlling quantum interference. This study shows solvents can switch conductance between destructive and constructive quantum interference pathways.
Area of Science:
- Molecular electronics
- Quantum transport phenomena
Background:
- Solvents significantly influence electrical conductance in single-molecule junctions.
- Protic solvents can form hydrogen bonds and induce electrostatic gating, affecting molecular properties.
Purpose of the Study:
- To investigate how protic solvents modulate single-molecule junction conductance.
- To demonstrate the switching of conductance between destructive quantum interference (DQI) and constructive quantum interference (CQI) using solvents.
- To explore the role of hydrogen bonding and electrostatic gating in controlling quantum interference.
Main Methods:
- Synthesis of two regioisomers: BIT-Zwitterion and BIT-Neutral.
- Measurement of single-molecule conductances using scanning-tunneling-microscope-based break junction technique.
- Theoretical analysis using density functional theory and quantum transport theory.
Main Results:
- Protic solvents alter BIT-Zwitterion geometry via hydrogen bonds, increasing HOMO-LUMO gap and decreasing conductance.
- Protic solvents induce a conformational change in BIT-Neutral, switching from DQI to CQI and increasing conductance.
- Solvent-induced stacking in BIT-Neutral creates an additional through-space transport pathway, further enhancing conductance.
Conclusions:
- Solvent choice and molecular regioisomerism offer a versatile strategy for controlling quantum interference and single-molecule conductance.
- Hydrogen bonding, electrostatic gating, and through-space transport are key mechanisms modulated by protic solvents.
- This work provides a pathway for precisely tuning molecular conductance for electronic applications.
Related Concept Videos
¹H NMR: Long-Range Coupling
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene...
Hydrogen Bonds
Hydrogen Bonds Control the World!
Because hydrogen has very weak electronegativity when it binds with a strongly electronegative atom, such as oxygen or nitrogen, electrons in the bond are unequally shared....
Spin–Spin Coupling Constant: Overview
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must...
IR Spectrum Peak Broadening: Hydrogen Bonding
However, the extent of hydrogen bonding influences the observed stretching frequency and band broadening. Intermolecular or intramolecular...
Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the...
Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...

