Abstract
A graphene fragment is a benzenoid graph that its dualist graph is a unicyclic graph. In particular, when the dualist graph of a benzenoid graph is a circle, it is called cyclofusene. In this paper, we determine the Clar number of a cyclofusene graph, and prove a bound for the Clar number of the graphene fragment. Moreover, we construct the graphene fragment which can attain this bound. More precisely, it is shown that the Clar number of the graphene fragment with n hexagons is at most \([\frac{2n}{3}]\).
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References
H. Abeledo, G.W. Atkinson, Unimodularity of the Clar number problem. Linear Algebra Appl. 420, 441–448 (2007)
M.B. Ahmadi, E. Farhadi, V. Amiri Khorasani, On computing the Clar number of a fullerene using optimization techniques. MATCH Commun. Math. Comput. Chem. 75, 695–701 (2016)
T. Bocchi, M. Lewinter, S. Karimi, On the Distribution of \(\pi \) Bonds in Cyclofusene. J. Math. Chem. 35(4), 339–344 (2004)
E. Clar, The Aromatic Sextet (Wiley, London, 1972)
J.E. Graver, E.J. Hartung, Internal \(Kekul\acute{e}\) structures for graphene and general patches. MATCH Commun. Math. Comput. Chem. 76, 693–705 (2016)
J.E. Graver, E.J. Hartung, A.Y. Souid, Clar and Fries numbers for benzenoids. J. Math. Chem. 51, 1981–1989 (2013)
I. Gutman, S.J. Cyvin, Introduction to the Theory of Benzenoid Hydrocarbons (Springer, Berlin, 1989)
P. Hansen, M. Zheng, The Clar number of a benzenoid hydrocarbon and linear programming. J. Math. Chem. 15, 93–107 (1994)
P. Hansen, M. Zheng, Upper bounds for the Clar number of a benzenoid hydrocarbon. J. Chem. Soc. Faraday Trans. 88, 1621–1625 (1992)
E. Hartung, Fullerenes with complete Clar structure. Discrete Appl. Math. 161, 2952–2957 (2013)
S. Klavzar, P. Zigert, I. Gutman, Clar number of catacondensed benzenoid hydrocarbons. J. Mol. Struct. Theochem. 586, 235–240 (2002)
K. Salem, I. Gutman, Clar number of hexagonal chains. Chem. Phys. Lett. 394, 283–286 (2004)
K. Salem, S. Klavzar, A. Vesel, P. Zigert, The Clar formulas of a benzenoid system and the resonance graph. Discrete Appl. Math. 157, 2565–2569 (2009)
L. Shi, H. Zhang, Forcing and anti-forcing numbers of (3,6)-Fullerenes. MATCH Commun. Math. Comput. Chem. 76, 597–614 (2016)
Z.F. Wei, H. Zhang, Number of matchings of low order in (4,6)-fullerene graphs. MATCH Commun. Math. Comput. Chem. 77, 707–724 (2017)
D. Ye, H. Zhang, Extremal fullerene graphs with the maximum Clar number. Discrete Appl. Math. 157, 3152–3173 (2009)
H. Zhang, D. Ye, An Upper Bound for the Clar Number of Fullerene Graphs. Math. Chem. 41, 123–133 (2007)
S. Zhai, D. Alrowaili, D. Ye, Clar structures vs Fries structures in hexagonal systems. Appl. Math. Comput. 329, 384–394 (2018)
Bai Nino, Istven Estelyi, R. Krekovski et al., On the Clar number of benzenoid graphs. MATCH Commun. Math. Comput. Chem. 80(1), 173–188 (2017)
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Tian, Y., Zhao, B. On the Clar number of graphene fragment. J Math Chem 59, 542–553 (2021). https://doi.org/10.1007/s10910-021-01214-w
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DOI: https://doi.org/10.1007/s10910-021-01214-w