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...

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...

A recently published paper [T. Došlić, this journal 3 (2012) 25-34] considers the Zagreb indices of benzenoid systems, and points out their low discriminativity. We show that analogous results hold for a variety of vertex-degree-based molecular structure descriptors that are being studied in contemporary mathematical chemistry. We also show that these results are straightforwardly obtained by u...

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...

The Szeged index (Sz) is a recently proposed1q2 structural descriptor, based on the distances of the vertices of the molecular graph. In order to be able to study the properties of this novel topological index it would be advantageous to possess an easy method for its calculation. The calculation of Sz directly from its definition (see below) is quite cumbersome, especially in the case of large...

An efficient algorithm leading to the Fries canonical structure is presented for benzenoid hydrocarbons. This is a purely topological approach, which is based on adjacency matrices and the Hadamard procedure of matrix multiplication. The idea is presented for naphthalene, as an example. The Fries canonical-structures are also derived for anthracene, coronene, triphenylene, phenanthrene, benz[a]...