Related Experiment Video
Updated: Aug 7, 2025
10:44
Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
10.9K
Conductance of o-carborane-based wires with different substitution patterns
Shi-Nuo Xu1, Yan Zheng2, Jing-Yao Ye2
1Department of Chemistry, Fuzhou University, Fuzhou 350108, China. yanjianfeng@fzu.edu.cn.
Dalton Transactions (Cambridge, England : 2003)
|March 14, 2023
Summary
We synthesized novel ortho-carborane molecular wires with multiple conduction channels. Their 3D structure enhances charge transport and junction stability compared to phenyl wires, offering design insights.
Area of Science:
- Molecular electronics
- Nanotechnology
- Materials science
Background:
- Single-molecule conductance measurements are crucial for understanding charge transport at the nanoscale.
- Carborane-based molecular wires offer unique structural and electronic properties for electronic applications.
Purpose of the Study:
- To synthesize and characterize ortho-carborane-based molecular wires with multiple conduction channels.
- To investigate the effect of carborane's 3D structure on charge transport compared to phenyl-based systems.
- To explore the role of quantum interference and multiple conduction pathways in molecular conductance.
Main Methods:
- Synthesis of ortho-carborane and phenyl-centered molecular wires.
- Single-molecule conductance measurements using scanning tunneling microscope break junction (STM-BJ) technique.
- Theoretical calculations to understand charge transport mechanisms.
Main Results:
- Successfully synthesized three ortho-carborane-based molecular wires (ortho-, meta-, and para-CN).
- Observed enhanced through-space transmission and stable molecular junction formation in carborane wires compared to phenyl analogs.
- Attributed significant conductance variations to multiple conduction channels and quantum interference effects.
Conclusions:
- The 3D structure of ortho-carborane effectively promotes charge transport and junction stability in molecular wires.
- Multi-channel conduction and quantum interference are key factors influencing the conductance of these systems.
- Findings provide guidelines for designing advanced ortho-carborane-based multichannel molecular wires for molecular electronics.
Related Concept Videos
02:30Stability of Substituted Cyclohexanes
12.7K
This lesson discusses the stability of substituted cyclohexanes with a focus on energies of various conformers and the effect of 1,3-diaxial interactions.
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
12.7K
02:02Chair Conformation of Cyclohexane
14.8K
The chair conformation is the most stable form of cyclohexane due to the absence of angle and torsional strain. The absence of angle strain is a result of cyclohexane’s bond angle being very close to the ideal tetrahedral bond angle of 109.5° in its chair conformer. Similarly, the torsional strain is also absent owing to the perfectly staggered arrangement of bonds.
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this...
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this...
14.8K
02:11Conformations of Cyclohexane
12.7K
Cyclohexane does not exist in a planar form due to the high angle and torsional strain it would experience in the planar structure. Instead, it adopts non-planar chair and boat conformations.
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal...
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal...
12.7K
01:14π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds
1.2K
In aromatic compounds, such as benzene, the circulation of (4n + 2) π-electrons sets up a diamagnetic or diatropic ring current around the perimeter of the molecule. This current induces a magnetic field that opposes the external field inside the ring and reinforces it on the outside. The protons in benzene are deshielded and exhibit high chemical shifts in the range 6.5–8.5 ppm. The shielding effect at the center of the ring is evident in complex aromatic molecules, such as...
1.2K
02:29Conformations of Cycloalkanes
11.9K
Adolf von Baeyer attempted to explain the instabilities of small and large cycloalkane rings using the concept of angle strain — the strain caused by the deviation of bond angles from the ideal 109.5° tetrahedral value for sp3 hybridized carbons. However, while cyclopropane and cyclobutane are strained, as expected from their highly compressed bond angles, cyclopentane is more strained than predicted, and cyclohexane is virtually strain-free. Hence, Baeyer’s theory that...
11.9K
02:10Carbocations
11.4K
Carbocations are one of the reaction intermediates formed during several nucleophilic substitutions or elimination reactions. A carbocation is an electron-deficient species with the central carbon atom having six electrons and three bonded atoms. The central carbon in a carbocation is sp2 hybridized with trigonal planar geometry. It has an empty p orbital perpendicular to the plane of the structure that can accept electrons. Thus, carbocations act as strong electrophiles and may react with any...
11.4K