10.1002/anie.201907030
Angewandte Chemie International Edition
RESEARCH ARTICLE
Figure 9. Calculated (B3LYP/6-31G(d,p)) frontier molecular orbitals and energy level diagrams of the four superbenzoquinones.
[1] (a) S. P. Roche, J. A. Porco Jr., Angew. Chem. Int. Ed. 2011, 50, 4068. (b)
Y. Li, S. Zhu, J. Li, A. Li, J. Am. Chem. Soc. 2016, 138, 3982. (c) G. Zhao,
G. Xu, C. Qian, W. Tang, J. Am. Chem. Soc. 2017, 139, 3360.
level was estimated to be -5.32/-4.20, -5.02/-4.29, -5.51/-4.22,
and -5.11/-4.34 eV, for SBQ-2O-p, SBQ-2O-o, SBQ-4O, and
SBQ-6O, respectively. Thus, SBQ-6O with six ketone groups has
the lowest-lying LUMO energy level due to the high
electronegativity of the C=O group. For comparison, molecules
SBQ-2O-p, SBQ-2O-o, SBQ-4O, and SBQ-6O were calculated
to have a HOMO/LUMO energy level of -5.27/-3.68, -5.00/-3.89, -
5.46/-3.78, and -5.65/-4.19 eV, respectively (Figure 9), and the
trend is also in agreement with the electrochemical
measurements.
[2] (a) C. Song, X. Ma, Appl. Cat. B: Environ. 2003, 41, 207. (b) S. Khan, S.
Gupta, N. Gupt, Biotechnol. Lett. 2018, 40, 1329.
[3] (a) D. R. Buckle, "Chloranil" in Encyclopedia of Reagents for Organic
Synthesis, 2001, John Wiley. (b) W. Brown, A. B. Turner, J. Chem. Soc. C:
Org. 1971, 2566.
[4] B. Huskinson, M. P. Marshak, C. Suh, S. Er, M. R. Gerhardt, C. J. Galvin, X.
Chen, A. Aspuru-Guzik, R. G. Gordon, M. J. Aziz, Nature 2014, 505, 195.
[5] (a) H. Zolllinger, Color Chemistry, 3rd Edition, Wiley-VCH, 2001. (b) H.-S.
Bien, J. Stawitz, K. Wunderlich, Anthraquinone dyes and intermediates,
Ulmann’s Encyclopedia of Industrial Chemistry, 2012, Vol. 3, p. 513.
[6] (a) K. Dimroth, W. Umbach, K. H. Blocher, Angew. Chem. Int. Ed. 1963, 2,
620. (b) L. A. Wendling, R. West, J. Org. Chem. 1978, 43, 1573. (c) E. D.
Wellman, K. R. Lassila, R. West J. Org. Chem. 1984, 49, 965. (d) K.
Takahashi, T. Suzuki, J. Am. Chem. Soc. 1989, 111, 5485. (e) R. West, J.
A. Jorgenson, K. L. Stearly, J. C. Calabrese, J. Chem. Soc., Chem.
Commun. 1991, 2, 1234. (f) P. Boldt, D. Bruhnke, F. Gerson, M. Scholz, P.
G. Jones, F. Bar, Helv. Chim. Acta 1993, 76,1739. (g) H. Kuata, T. Tanaka,
M. Oda, Chem. Lett. 1999, 28, 749. (h) T. Takahashi, K. Matsuoka, K.
Takimiya, T. Otsubo, Y. Aso, J. Am. Chem. Soc. 2005, 127, 8928. (i) R. P.
Ortiz, J. Casado, V. Hernández, J. T. L. Navarrete, P. M. Viruela, E. Ortí, K.
Takimiya, T. Otsubo, Angew. Chem. Int. Ed. 2007, 46, 9057. (j) K. Zhang,
K. Huang, J. Li, J. Luo, C. Chi, J. Wu, Org. Lett. 2009, 11, 4854. (h) S. D.
Motta, F. Negri, D. Fazzi, C. Castiglioni, E. V. Canesi, J. Phys. Chem. Lett.
2010, 1, 3334. (k) A. Ueda, S. Nishida, K. Fukui, T. Ise, D. Shiomi, K. Sato,
T. Takui, K. Nakasuji, Y. Morita, Angew. Chem. Int. Ed. 2010, 49, 1678. (l)
E. V. Canesi, D. Fazzi, L. Colella, C. Bertarelli, C. Castiglioni, J. Am. Chem.
Soc. 2012, 134, 19070. (m) D. Schmidt, M. Son, M. J. Lim, M.-J. Lin, I.
Krummenacher, H. Braunschweig, D. Kim, F. Wurthner, Angew. Chem. Int.
Ed. 2015, 54, 13980. (n) H. Wei, L. Zhang, H. Phan, X. Huang, T. S. Herng,
J. Zhou, W. Zeng, J. Ding, S. Luo, J. Wu, Z. Zeng, Chem. Eur. J. 2017, 23,
9419. (o) K. Naoda, D. Shimizu, O. J. Kim, K. Furukawa, D. Kim, A. Osuka,
Chem. Eur. J. 2017, 23, 8969. (p) S. Lee, F. Miao, H. Phan, T. S. Herng, J.
Ding, J. Wu, D. Kim, ChemPhysChem 2017, 18, 591. (q) R. Rausch, D.
Schmidt, D. Bialas, I. Krummenacher, H. Braunschweig, F. Würthner, Chem.
Eur. J. 2018, 24, 3420-3424. (r) F. Miao, H. Phan, J. Wu, Molecules 2019,
24, 1446.
Conclusion
In summary, we successfully synthesized
a
series of
superbenzoquinone-based diradicaloid, tetraradicaloid, and
hexaradicaloid via a stepwise de-aromatization approach from the
respective di-/tetra-/hexafluoro- HBC intermediates. The non-
aromatic and quinoidal character of the obtained compounds was
demonstrated by X-ray crystallographic analysis and theoretical
calculations. These quinoidal compounds, however, have intrinsic
tendency to recover aromaticity and thus display open-shell multi-
radical character with magnetic activity. The radical character,
singlet-triplet energy gap, optical properties, and electrochemical
properties of these open-shell singlet species are dependent on
the structure and molecular symmetry. Our studies provide a new
synthetic method to access various PAH-based quinones with
tunable physical properties and give some insights into the
fundamental structure-radical character-electronic property
relationships.
Acknowledgements
We acknowledge financial support from the MOE Tier 3
programme (MOE2014-T3-1-004), NRF Investigatorship (NRF-
NRFI05-2019-0005) and MOE Tier 2 grant (MOE2018-T2-2-094).
[7] (a) T. M. Pappenfus, R. J. Chesterfield, C. D. Frisbie, K. R. Mann, J. Casado,
J. D. Raff and L. L. Miller, J. Am. Chem. Soc. 2002, 124, 4184. (b) R. J.
Chesterfield, C. R. Newman, T. M. Pappenfus, P. C. Ewbank, M. H.
Haukaas, K. R. Mann, L. L. Miller and C. D. Frisbie, Adv. Mater. 2003, 15,
1278. (c) S. Handa, E. Miyazaki, K. Takimiya and Y. Kunugi, J. Am. Chem.
Soc. 2007, 129, 11684. (d) D. E. Janzen, M. W. Burand, P. C. Ewbank, T.
M. Pappenfus, H. Higuchi, D. A. da Silva Filho, V. G. Young, J. L. Brédas
Keywords: quinone
•
diradicaloid
•
polycyclic aromatic
hydrocarbon • aromaticity • de-aromatization
References
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