Our investigations are motivated by recent papers concerning the spectral moments of the edge-adjacency matrix, which were successfully employed in QSAR and QSPR studies of different classes of compounds [Estrada, E. J. Chem. Inf. Comput. Sci. 1996, 36, 844-849; 1997, 37, 320-328; 1998, 38, 23-27]. In this work, the evaluation of the 10th spectral moment of the vertex-adjacency matrix for pheny...

The main topological characteristics of altan-benzenoids were established. In particular, it was shown that the perimeter of Kekuléan altan-benzenoids is of size 4k , having a destablizing (anti-aromatic) energy effect, similar to (4k)-annulenes.

Three new benzenoid derivatives, lawsoinermone (1), inermidioic acid (2), and inermic acid (3) have been isolated from the aerial part of Lawsonia inermis, together with 11 known compounds (4-14). The structures of three new compounds were determined through spectroscopic and MS analyses. Compounds 1, 4-6, 13 and 14 were evaluated for inhibition of nitric oxide production in LPS-stimulated prod...

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Coronoids with holes shaped like an odd carbon benzenoid have antiaromatic holes and antiaromatic conjugated circuits. Another class of concealed diradical coronoids has been identified. They are Hückel molecular orbital diradicals (HOMO = LUMO = 0, each with a single electron occupancy) that have VB (valence-bond) structures (K 0).This new class of concealed diradical coronoids have more enhan...

The Wiener index W is the sum of distances between all pairs of vertices of a (connected) graph. Hexagonal systems (HS’s) are a special type of plane graphs in which all faces are bounded by hexagons. These provide a graph representation of benzenoid hydrocarbons and thus find applications in chemistry. The paper outlines the results known for W of the HS: method for computation of W , expressi...

Fibonacenes (zig-zag unbranched catacondensed benzenoid hydrocarbons) are a class of polycyclic conjugated systems whose molecular graphs possess remarkable properties, often related with the Fibonacci numbers. This article is a review of the chemical graph theory of fibonacenes, with emphasis on their Kekulé–structure–related and Clar–structure–related properties. ————————————————— ∗Supported ...