Related Experiment Video
Updated: Dec 23, 2025
Engineering Molecular Recognition with Bio-mimetic Polymers on Single Walled Carbon Nanotubes
Published on: January 10, 2017
Dewar Benzenoids Discovered In Carbon Nanobelts
Magnus W D Hanson-Heine1, David M Rogers1, Simon Woodward1
1School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, U.K.
Abstract:
The synthesis of cyclacene nanobelts remains an elusive goal dating back over 60 years. These molecules represent the last unsynthesized building block of carbon nanotubes and may be useful both as seed molecules for the preparation of structurally well-defined carbon nanotubes and for understanding the behavior and formation of zigzag nanotubes more broadly. Here we report the discovery that isomers containing two Dewar benzenoid rings are the preferred form for several sizes of cyclacene. The predicted lower polyradical character and higher singlet-triplet stability that these isomers possess compared with their pure benzenoid counterparts suggest that they may be more stable synthetic targets than the structures that have previously been identified. Our findings should facilitate the exploration of new routes to cyclacene synthesis through Dewar benzene chemistry.
Related Concept Videos
01:34NMR Spectroscopy of Benzene Derivatives
01:07Structure of Benzene: Kekulé Model
He proposed that benzene has a cyclic structure of six carbon atoms attached to one hydrogen atom each, with three alternating pi bonds.
01:18Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism
01:16Structure of Conjugated Dienes
Conjugated dienes are compounds characterized by the presence of alternating double and single bonds. In a conjugated system like 1,3-butadiene, the unhybridized 2p orbital on each carbon overlaps continuously, allowing the π electrons to be delocalized across the entire molecule. In contrast, this type of overlap does not occur in cumulated and isolated dienes, such as 2,3-pentadiene and 1,4-pentadiene, respectively. Instead, the π electrons remain localized between the double...
01:24π Molecular Orbitals of 1,3-Butadiene
The simplest conjugated diene is 1,3-butadiene: a four-carbon system where each carbon is sp2-hybridized and has an unhybridized p orbital that contains an unpaired electron. According to molecular orbital theory, atomic orbitals combine to form molecular orbitals such that the number...
01:29Diels–Alder Reaction: Characteristics of Dienes
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is more stable,...