Octazethrene and Its Isomer with Different Diradical Characters and Chemical Reactivity: The Role of the Bridge Structure

Pan Hu, Sangsu Lee, Kyu Hyung Park, Soumyajit Das, Tun Seng Herng, Theo Goncalves, Kuo-Wei Huang, Jun Ding, Dongho Kim, Jishan Wu

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39 Scopus citations


The fundamental relationship between structure and diradical character is important for the development of open-shell diradicaloid-based materials. In this work, we synthesized two structural isomers bearing a 2,6-naphthoquinodimethane or a 1,5-naphthoquinodimethane bridge and demonstrated that their diradical characters and chemical reactivity are quite different. The mesityl or pentafluorophenyl substituted octazethrene derivatives OZ-M/OZ-F and their isomer OZI-M (with mesityl substituents) were synthesized via an intramolecular Friedel-Crafts alkylation followed by oxidative dehydrogenation strategy from the key building blocks 4 and 11. Our detailed experimental and theoretical studies showed that both isomers have an open-shell singlet ground state with a remarkable diradical character (y0 = 0.35 and 0.34 for OZ-M and OZ-F, and y0 = 0.58 for OZI-M). Compounds OZ-M and OZ-F have good stability under the ambient environment while OZI-M has high reactivity and can be easily oxidized to a dioxo-product 15, which can be correlated to their different diradical characters. Additionally, we investigated the physical properties of OZ-M, OZ-F and 15.
Original languageEnglish (US)
Pages (from-to)2911-2919
Number of pages9
JournalThe Journal of Organic Chemistry
Issue number7
StatePublished - Mar 21 2016

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: J. W. acknowledges the financial support from the MOE Tier 3 Programme (MOE2014-T3-1-004), Tier 2 grant (MOE2014-T2-1-
080) and A*STAR JCO grant (1431AFG100). This work at Yonsei University was supported by the Global Frontier R&D Program
on Center for Multiscale Energy System funded by the National Research Foundation under the Ministry of Science, ICT & Future,
Korea (NRF-2014M3A6A7060583). We thank Dr. Tan Geok Kheng and Dr. Bruno Donnadieu for the crystallographic analysis.


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