In this work we wish to report a method for computing the adjacency matrix of benzenoid hydrocarbons from their boundary codes. The carbon skeletons of benzenoids will be depicted by graphs, called benzenoid graphs• , which can be constructed in the plane by assembhng h regular hexagons in such a way that two hexagons have exactly one joint edge or are disjoint, and the covered area in the plan...

In a series of publications Estrada (Estrada, E. J. Chem. Inf. Comput. Sci. 1996, 36, 844-849; 1997 37, 320-328; 1998, 38, 23-27) employed spectral moments of line graphs in QSPR and QSAR relationship studies of various classes of compounds. A recent paper (Marković, S.; Gutman, I. J. Chem. Inf Comput. Sci. 1999, 39, 289-293) reported that in QSPR and QSAR investigations of benzenoid hydrocarbo...

In this paper the Clar covering polynomial of a hexagonal system is introduced. In fact it is a kind of F polynomial [4] of a graph, and can be calculated by recurrence relations. We show that the number of aromatic sextets (in a Clar formula), the number of Clar formulas, the number of Kekule structures and the first Herndon number for any Kekulean hexagonal system can be easily obtained by it...

The first and second Hyper-Zagreb index of a connected graph $G$ is defined by $HM_{1}(G)=\sum_{uv \in E(G)}[d(u)+d(v)]^{2}$ $HM_{2}(G)=\sum_{uv E(G)}[d(u).d(v)]^{2}$. In this paper, the indices certain graphs are computed. Also bounds for determined. Further linear regression analysis degree based with boiling points benzenoid hydrocarbons carried out. model, on index, better than models corre...

JERRY RAY DIAS. Can. J. Chem. 62, 2914 (1984). A new concept for isomer enumeration of peri-condensed benzenoid hydrocarbons (PAH6) based on the enumeration of their excised internal structures is presented. Formulas corresponding only to strictly peri-condensed benzenoid hydrocarbons can be identified from a previously derived Formula Periodic Table for PAH6. The number of benzenoid PAH6 isome...

The exact biosynthetic pathways leading to benzoic acid (BA) formation in plants are not known, but labeling experiments indicate the contribution of both beta-oxidative and non-beta-oxidative pathways. In Petunia hybrida BA is a key precursor for the production of volatile benzenoids by its flowers. Using functional genomics, we identified a 3-ketoacyl-CoA thiolase, PhKAT1, which is involved i...

As a strengthening of the concept global forcing number graph G, complete G is cardinality minimum edge subset to which restriction every perfect matching M set M. Xu et al. (J Comb Opt 29: 803–814, 2015) revealed that also antifores each matching, and obtained for catacondensed hexagonal system, equal Clar plus hexagons (Chan MATCH Commun Math Comput Chem 74: 201–216, 2015). In this paper, we ...

After an introduction on the history of polycyclic aromatic compounds, recent advances in the theory of benzenoids are briefly reviewed. Then using systems with 4, 5, or 6 benzenoid rings for illustration, the partition of the P π-electrons among the rings of the benzenoid is presented, followed by a different way of examining the distribution of these π-electrons which is called the signature ...

If G is a connected graph with vertex set V (G), then the degree distance of G is defined as DD(G) = ∑ {u,v}∈V (G)(deg u + deg v)d(u, v), where deg u is the degree of vertex u, and d(u, v) denotes the distance between u and v. In the chemical literature, DD(G) is better known under ‡Corresponding author. If possible, send your correspondence via e-mail. the name Schultz index. In the class of p...