Dewar Benzenoids Discovered In Carbon Nanobelts.

Magnus W D Hanson-Heine,Jonathan D Hirst,David M Rogers,Simon Woodward

doi:10.1021/acs.jpclett.0c01027

Magnus W D Hanson-Heine, Jonathan D Hirst + Show 2 more

Open Access

https://doi.org/10.1021/acs.jpclett.0c01027

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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.

Highlights

The synthesis of cyclacene nanobelts remains an elusive goal dating back over 60 years
Since their conception by Heilbronner in 1954,1 cyclacenes have been the focus of extensive ongoing attempts at both synthesis and theoretical characterization.[2]
Cyclacenes are interesting highly aromatic molecules. They can be considered as having two different types of π-electron system, one comprising an arenoid belt made up of fused benzene rings and the other consisting of two peripheral circuits formed from two fused trans-polyene ribbons called trannulenes.[3]

Summary

Introduction

The synthesis of cyclacene nanobelts remains an elusive goal dating back over 60 years. The cyclacene isomers with no Dewar benzenoids are the most stable form at ring sizes of n

Results

Conclusion