Acta Phys. -Chim. Sin. ›› 2018, Vol. 34 ›› Issue (6): 639-649.

• ARTICLE •

### Aromaticity Study of Benzene-Fused Fulvene Derivatives Using the Information-Theoretic Approach in Density Functional Reactivity Theory

Donghai. YU1,Chunying. RONG1,*(),Tian. LU2,Frank. DE PROFT3,*(),Shubin. LIU4,*()

1. 1 Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, P. R. China
2 Beijing Kein Research Center for Natural Sciences, Beijing 100022, P. R. China
3 Research Group of General Chemistry (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
4 Research Computing Center, University of North Carolina, Chapel Hill, NC 27599-3420, USA
• Received:2017-08-31 Published:2018-03-20
• Contact: Chunying. RONG,Frank. DE PROFT,Shubin. LIU E-mail:rongchunying@aliyun.com;fdeprof@vub.ac.be;shubin@email.unc.edu
• Supported by:
CYR and SBL acknowledge support from the National Natural Science Foundation of China (21503076) and Hunan Provincial Natural Science Foundation of China (2017JJ3201). DHY acknowledges the support from the Hunan Provincial Innovation Foundation for Postgraduates (CX2017B179), and China Scholarship Council (201706720015). FDP acknowledges the Research Foundation Flanders (FWO) for continuous support to his group and the Vrije Universiteit Brussel for support, among other through a Strategic Research Program awarded to his group. Finally, FDP acknowledges the Francqui foundation for a position as Francqui Research Professor

Abstract:

Although a large variety of aromatic systems have been unveiled in the literature, justifying their origin of stability and understanding their nature of aromaticity is still an unaccomplished task. In this work, using tools recently developed by us within the density functional reactivity theory framework, where we employ simple density functionals to quantify molecular structural and reactivity properties, we examine the aromaticity concept from a different perspective. Using six quantities from the information-theoretic approach, namely, the Shannon entropy, Fisher information, Ghosh-Berkowitz-Parr entropy, Onicescu information energy, information gain, and relative Rényi entropy, and four aromaticity descriptors, namely, the aromatic stabilization energy (ASE) index, the harmonic oscillator model of aromaticity (HOMA) index, the aromatic fluctuation (FLU) index, and the nucleus-independent chemical shift (NICS) index, we systematically examined the correlations between substituted fulvene derivatives fused with one, two, and three benzene rings. Among the 14 benzofulvene derivatives studied in this work, there were seven single-fused, four double-fused, and three triple-fused benzofulvene derivatives. Our results show that the aromaticity indexes are often well correlated with one another. The same is true for information-theoretic quantities. Moreover, these correlations are valid across all series of benzofulvene derivatives with different ring structures. The cross-correlations between information-theoretic quantities and aromaticity indexes were usually strong. However, two completely opposite patterns were observed; as a consequence, these correlations are not valid across all series of benzofulvene derivatives. The nature of these correlations depends on the nature of the ring structure. The two groups of systems, each obeying the same cross-correlation patterns, have a total number of 4n + 2 and 4n π electrons, respectively, which are in agreement with Hückel's rule of aromaticity and antiaromaticity. Compared with the results obtained for systems without a benzene fused ring, the correlation patterns of these quantities were always found to be the same, both with and without fused benzene rings. This suggests that, despite benzene's aromaticity, its fusion with a fulvene moiety does not modify the aromaticity and antiaromaticity of the fulvene ring. These results confirm that the fusion of benzene rings with a fulvene moiety has no influence on the aromatic nature of the fulvene moiety. Thus, the aromaticity and antiaromaticity of benzene-fused fulvene derivatives are solely determined by the fulvene moiety. These results should provide a new understanding of the origin and nature of aromaticity and antiaromaticity.

MSC2000:

• O641