Ein einfaches graphentheoretisches Verfahren zur Abschatzung der Resonanz- und Grenzorbitalenergien alternierender polycyclisdier aromatisdier Kohlenwasserstoffe / A Simple Graph-theoretical Scheme for the Estimation of Resonance and Frontier Orbital Energies of Alternant Polycyclic Aromatic Hydrocarbons

1981 ◽  
Vol 36 (3) ◽  
pp. 276-279 ◽  
Author(s):  
K.-D. Gundermann ◽  
C. Lohberger ◽  
M. Zander

From the characteristic graphs of alternant polycyclic aromatic hydrocarbons (kata-annellated and peri-condensed systems) a topological index is derived, which can be calculated very easily even for highly complex aromatic systems and correlates satisfactorily with both the Dewar resonance and HMO frontier orbital energies. The graph-theoretical scheme provides a simple means for the rapid estimation of these data for unknown aromatic systems

1981 ◽  
Vol 36 (11) ◽  
pp. 1217-1221
Author(s):  
K.-D. Gundermann ◽  
C. Lohberger ◽  
M. Zander

The half-sum of the distance matrix elements derived from the characteristic graphs, i.e. the Wiener number of these graphs is proposed as a new topological index for alternant polycyclic aromatic hydrocarbons. It is shown by regression analysis that correlations between topological indices and electronic properties of alternant aromatic systems do only exist for those indices and properties which depend to the same degree from the size of the systems and for which the corresponding relation applies to the topology.


2021 ◽  
Vol 18 ◽  
Author(s):  
Muhammad Javaid ◽  
Muhammad Ibraheem ◽  
Abdul Raheem

Introduction: A graph is supposed to be regular if all vertices have equal degree, otherwise irregular. Materials and Methods: Polycyclic aromatic hydrocarbons are important combusting material and considered as class of carcinogens. These polycyclic aromatic hydrocarbons play an important role in graphitisation of medical science. A topological index is a function that assigns a numerical value to a (molecular) graph which predicts various physical, chemical, biological, thermodynamical and structural properties of (molecular) graphs. An irregular index is a topological index that measures the irregularity of atoms with respect to their bonding for the chemical compounds which are involved in the under studying graphs. Results and Discussion: In this paper, we will compute an analysis of distance based irregular indices of polycyclic aromatic hydrocarbons. A comparison among the obtained indices with the help of their numerical values and the 3D presentations is also included. The efficient and steady indices of polycyclic aromatic hydrocarbons are addressed in the form of their irregularities. Conclusion: Connection based study of the molecular graphs is more suitable than the degree based irregularity indices.


Mathematics ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 467
Author(s):  
Andrey A. Dobrynin ◽  
Ali Iranmanesh

The Wiener index is a topological index of a molecular graph, defined as the sum of distances between all pairs of its vertices. Benzenoid graphs include molecular graphs of polycyclic aromatic hydrocarbons. An edge thorny graph G is constructed from a catacondensed benzenoid graph H by attaching new graphs to edges of a perfect matching of H. A formula for the Wiener index of G is derived. The index of the resulting graph does not contain distance characteristics of elements of H and depends on the Wiener index of H and distance properties of the attached graphs.


Author(s):  
Donatella Loru ◽  
Amanda L Steber ◽  
Pablo Pinacho ◽  
Sébastien Gruet ◽  
Berhane Temelso ◽  
...  

We report on the noncovalent intermolecular interactions established between the polycyclic aromatic hydrocarbons phenanthrene and phenanthridine with water. Such noncovalent interactions involving extended aromatic systems and water molecules are ubiquitous...


1985 ◽  
Vol 40 (6) ◽  
pp. 636-638 ◽  
Author(s):  
M. Zander

The hydrogen-depleted graphs of polycyclic aromatic hydrocarbons contain two types of vertices (with regard to their degree) and correspondingly three types of edges. The respective sums of these edges reflect the molecular topology of the hydrocarbons and were used for constructing a new topological index for kata-annellated aromatic hydrocarbons that correlates well with their topological resonance energies per electron. Dependent on the degrees of their first neighbours, the vertices of degree 2 of polycyclic hydrocarbons can be distinguished as to high, medium and low chemical reactivity of the corresponding carbon atoms, in agreement with the results from MO theory and experiments.


2019 ◽  
Vol 64 (1) ◽  
pp. 55-67
Author(s):  
Vlad Pӑnescu ◽  
◽  
Mihaela Cӑtӑlina Herghelegiu ◽  
Sorin Pop ◽  
Mircea Anton ◽  
...  

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