Related Experiment Video
Updated: Dec 11, 2025
08:18
Microscopic Visualization of Porous Nanographenes Synthesized through a Combination of Solution and On-Surface Chemistry
Published on: March 4, 2021
2.0K
Negatively Curved Nanographene with Heptagonal and [5]Helicene Units
Zijie Qiu1, Sobi Asako2, Yunbin Hu1
1Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
Journal of the American Chemical Society
|August 19, 2020
Summary
Negatively curved nanographene (NG) was synthesized unexpectedly. This novel material exhibits mechanochromic properties and solid-state emission, with potential applications in advanced materials.
Area of Science:
- Organic Chemistry
- Materials Science
- Nanotechnology
Background:
- Graphene derivatives are crucial in advanced materials.
- Exploring novel nanographene structures with unique properties is ongoing.
Purpose of the Study:
- To synthesize and characterize a novel negatively curved nanographene (NG).
- To investigate the structural, electronic, and optical properties of the synthesized NG.
Main Methods:
- Synthesis via aryl rearrangement and cyclodehydrogenations.
- Structural confirmation using X-ray crystallography.
- Theoretical calculations to support reaction mechanisms.
- Chiral high-performance liquid chromatography for enantiomer resolution.
- Circular dichroism spectroscopy for enantiomeric analysis.
Main Results:
- Unexpected synthesis of negatively curved nanographene (NG 4) with two heptagons and a [5]helicene moiety.
- X-ray crystallography confirmed saddle-shaped structures of intermediates and NG 4.
- Theoretical calculations favored aryl rearrangement over helicene formation.
- NG 4 displayed reversible mechanochromic color change and solid-state emission.
- Enantiomers of NG 4 exhibited moderate Cotton effects in circular dichroism spectra.
Conclusions:
- A novel negatively curved nanographene was successfully synthesized.
- The material possesses unique mechanochromic and photoluminescent properties.
- The study provides insights into the synthesis and properties of curved nanographenes.
Related Concept Videos
02:11Conformations of Cyclohexane
14.8K
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...
14.8K
02:57Coordination Number and Geometry
18.4K
For transition metal complexes, the coordination number determines the geometry around the central metal ion. Table 1 compares coordination numbers to molecular geometry. The most common structures of the complexes in coordination compounds are octahedral, tetrahedral, and square planar.
18.4K
01:07Radicals: Electronic Structure and Geometry
4.8K
This lesson delves into the geometry of a radical, which is influenced by the electronic structure of the molecule. The principle is similar to that of a lone pair, where the unpaired electron influences the geometry at the radical center.
Accordingly, the structure of a trivalent radical lies between the geometries of carbocations and carbanions. An sp2-hybridized carbocation is trigonal planar, while an sp3-hybridized carbanion is trigonal pyramidal. Here, the difference in geometry is...
Accordingly, the structure of a trivalent radical lies between the geometries of carbocations and carbanions. An sp2-hybridized carbocation is trigonal planar, while an sp3-hybridized carbanion is trigonal pyramidal. Here, the difference in geometry is...
4.8K
02:06Newman Projections
19.9K
Different notations are used to represent the three-dimensional structure of molecules on two-dimensional surfaces. One of the most commonly used representations is the dash-wedge formula. The dashed wedges, solid wedges, and the plane lines indicate the groups situated behind the plane, coming out of the plane, and in the plane, respectively.
The organic molecules rotate across the single bonds leading to numerous temporary three-dimensional structures of varying energy known as...
The organic molecules rotate across the single bonds leading to numerous temporary three-dimensional structures of varying energy known as...
19.9K
02:52VSEPR Theory and the Basic Shapes
81.1K
Overview of VSEPR Theory
81.1K
01:18Aromatic Hydrocarbon Cations: Structural Overview
3.5K
Cycloheptatriene is a neutral monocyclic unsaturated hydrocarbon that consists of an odd number of carbon atoms and an intervening sp3 carbon in the ring. The three double bonds in the ring correspond to 6 π electrons, which is a Huckel number, and therefore satisfies the criteria of 4n + 2 π electrons. However, the intervening sp3 carbon disrupts the continuous overlap of p orbitals. As a result, cycloheptatriene is not aromatic.
Removing one hydrogen from the intervening CH2 group...
Removing one hydrogen from the intervening CH2 group...
3.5K