Abstract Aromatic chemicals play indispensable roles in our daily lives, having broad applications household goods, textiles, healthcare, electronics and automotive, but their production currently relies on fossil resources that have heavy environmental burdens. Synthesis of aromatic from bio-based would be a viable approach to improve sustainability. However, very few methods are available for...

A topological descriptor is regarded as a numerical parameter derived by using mathematical tools from the molecular graph of different chemical structures. The theory paramount section chemistry. In this section, there are many parameters, that have very useful characteristics to study structure chemicals. article, we investigate indices concealed non-kekulean benzenoid hydrocarbon graph. We w...

The Padmakar-Ivan (PI) index is a Wiener-Szeged-like topological index which reflects certain structural features of organic molecules. The PI index of a graph G is the sum of all edges uv of G of the number of edges which are not equidistant from the vertices u and v. In this paper we obtain the second and third extremals of catacondensed hexagonal systems with respect to the PI index.

A VDB topological index is defined as

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.