Related Experiment Video
Updated: Apr 20, 2026
Preparation of a Corannulene-functionalized Hexahelicene by CopperI-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units
Published on: September 18, 2016
Aromaticity evaluations of planar [6]radialenes
Guillaume Berionni1, Judy I-Chia Wu2, Paul V R Schleyer2
1†Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 München, Germany.
Aromaticity in fused polycyclic systems depends on ring structure. Heterocyclic compounds exhibit radialene-like aromaticity, while polycyclic aromatic hydrocarbons like coronene show benzene-like characteristics, highlighting diverse aromatic behaviors.
Area of Science:
- Organic Chemistry
- Computational Chemistry
- Materials Science
Background:
- Fused polycyclic systems are crucial in organic chemistry and materials science.
- Understanding their aromatic character is key to predicting their properties and applications.
- Previous studies have explored various aspects of polycyclic aromaticity, but a comprehensive comparison across different fused systems remains an active area of research.
Purpose of the Study:
- To investigate the variation in aromatic character of fused polycyclic systems based on their annulated ring structures.
- To compare the aromaticity of heterocyclic fused congeners with well-known polycyclic aromatic hydrocarbons.
- To elucidate the multifaceted nature of aromaticity using multiple computational criteria.
Main Methods:
- Computation of extra cyclic resonance energies (ECREs) for a series of fused polycyclic systems, including heterocyclic congeners (1-5) and polycyclic aromatic hydrocarbons (triphenylene 9, coronene 10, isocoronene 11).
- Application of geometric criteria, specifically the harmonic oscillator model of aromaticity (HOMA).
- Utilisation of magnetic criteria, including nucleus independent chemical shifts (NICS).
Main Results:
- The central six-membered rings (6MRs) of heterocyclic fused congeners 1-5 were found to be '[6]radialene-like' in their aromatic character.
- In contrast, the central 6MRs of triphenylene 9, coronene 10, and isocoronene 11 exhibited 'benzene-like' aromaticity.
- Comparisons across ECREs, HOMA, and NICS criteria demonstrated the complex and varied nature of aromaticity in these systems.
Conclusions:
- The aromatic character of fused polycyclic systems is significantly influenced by the nature of their annulated rings.
- Heterocyclic fused systems display distinct aromaticity patterns compared to traditional polycyclic aromatic hydrocarbons.
- A multi-criteria approach is essential for a comprehensive understanding of aromaticity in diverse fused polycyclic structures.
More Related Videos
10:52Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex
Published on: July 27, 2022
11:45Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Related Concept Videos
01:18Aromatic Hydrocarbon Anions: Structural Overview
Due to the absence of continuous...
01:18Aromatic Hydrocarbon Cations: Structural Overview
Removing one hydrogen from the intervening CH2 group...
01:20Criteria for Aromaticity and the Hückel 4n + 2 Rule
For the first time, Eric Hückel, a German chemical physicist, derived a set of structural features for a compound to be classified as aromatic. This is now known as Hückel’s rule or...
01:18Frost Circles for Different Conjugated Systems
01:13Five-Membered Heterocyclic Aromatic Compounds: Overview
01:07Radicals: Electronic Structure and Geometry
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...