scholarly journals Physical-chemical properties studying of molecular structures via topological index calculating

Open Physics ◽  
2017 ◽  
Vol 15 (1) ◽  
pp. 261-269
Author(s):  
Jianzhang Wu ◽  
Mohammad Reza Farahani ◽  
Xiao Yu ◽  
Wei Gao

AbstractIt’s revealed from the earlier researches that many physical-chemical properties depend heavily on the structure of corresponding moleculars. This fact provides us an approach to measure the physical-chemical characteristics of substances and materials. In our article, we report the eccentricity related indices of certain important molecular structures from mathematical standpoint. The eccentricity version indices of nanostar dendrimers are determined and the reverse eccentric connectivity index for V-phenylenic nanotorus is discussed. The conclusions we obtained mainly use the trick of distance computation and mathematical derivation, and the results can be applied in physics engineering.

Open Physics ◽  
2017 ◽  
Vol 15 (1) ◽  
pp. 354-359 ◽  
Author(s):  
Hualong Wu ◽  
Muhammad Kamran Siddiqui ◽  
Bo Zhao ◽  
Jianhou Gan ◽  
Wei Gao

AbstractFrom the earlier studies in physical and chemical sciences, it is found that the physico-chemical characteristics of chemical compounds are internally connected with their molecular structures. As a theoretical basis, it provides a new way of thinking by analyzing the molecular structure of the compounds to understand their physical and chemical properties. In our article, we study the physico-chemical properties of certain molecular structures via computing the Ediz eccentric connectivity index from mathematical standpoint. The results we yielded mainly apply to the techniques of distance and degree computation of mathematical derivation, and the conclusions have guiding significance in physical engineering.


2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Wei Gao ◽  
Weifan Wang ◽  
Muhammad Kamran Jamil ◽  
Mohammad Reza Farahani

It is found from the earlier studies that the structure-dependency of totalπ-electron energyEπheavily relies on the sum of squares of the vertex degrees of the molecular graph. Hence, it provides a measure of the branching of the carbon-atom skeleton. In recent years, the sum of squares of the vertex degrees of the molecular graph has been defined as forgotten topological index which reflects the structure-dependency of totalπ-electron energyEπand measures the physical-chemical properties of molecular structures. In this paper, in order to research the structure-dependency of totalπ-electron energyEπ, we present the forgotten topological index of some important molecular structures from mathematical standpoint. The formulations we obtained here use the approach of edge set dividing, and the conclusions can be applied in physics, chemical, material, and pharmaceutical engineering.


2018 ◽  
Vol 74 (1-2) ◽  
pp. 25-33 ◽  
Author(s):  
Zahid Iqbal ◽  
Muhammad Ishaq ◽  
Adnan Aslam ◽  
Wei Gao

AbstractPrevious studies show that certain physical and chemical properties of chemical compounds are closely related with their molecular structure. As a theoretical basis, it provides a new way of thinking by analyzing the molecular structure of the compounds to understand their physical and chemical properties. The molecular topological indices are numerical invariants of a molecular graph and are useful to predict their bioactivity. Among these topological indices, the eccentric-connectivity index has a prominent place, because of its high degree of predictability of pharmaceutical properties. In this article, we compute the closed formulae of eccentric-connectivity–based indices and its corresponding polynomial for water-soluble perylenediimides-cored polyglycerol dendrimers. Furthermore, the edge version of eccentric-connectivity index for a new class of dendrimers is determined. The conclusions we obtained in this article illustrate the promising application prospects in the field of bioinformatics and nanomaterial engineering.


2018 ◽  
Vol 26 (2) ◽  
pp. 181-206
Author(s):  
Gul E Mehak ◽  
Akhlaq Ahmad Bhatti

Abstract A large number of drug experiments revealed that there exists strong inherent relation between the drugs molecular structures and the bio-medical and pharmacology characteristics. Due to the effectiveness for pharmaceutical and medical scientists of their ability to grasp the biological and chemical characteristics of new drugs, forgotten topological index was defined to analyze the drug molecular structures. This index is applicable for testing the chemical and pharmacological properties of drug molecular structures that can make up for lack of chemical experiments and can provide a theoretical basis for the manufacturing of drugs which is widely welcomed in developing areas. In this paper, based on the drug molecular structure analysis and vertex dividing technique with respect to their degrees, we present the forgotten topological index of the line graphs of several popular chemical structures which is quite common in drug molecular graphs.


2018 ◽  
Vol 16 (1) ◽  
pp. 1200-1206 ◽  
Author(s):  
Zeeshan Saleem Mufti ◽  
Muhammad Faisal Nadeem ◽  
Wei Gao ◽  
Zaheer Ahmad

AbstractA topological index is a map from molecular structure to a real number. It is a graph invariant and also used to describe the physio-chemical properties of the molecular structures of certain compounds. In this paper, we have investigated a chemical structure of pentacene. Our paper reflects the work on the following indices:Rα, Mα, χα, ABC, GA, ABC4, GA5, PM1, PM2, M1(G, p)and M1(G, p) of the para-line graph of linear [n]-pentacene and multiple pentacene.


Author(s):  
Cristina Mihali ◽  
◽  
Ionut Grad ◽  
Thomas Dippong ◽  
◽  
...  

The aim of this study was to evaluate the physical-chemical characteristics of different types of coffee, decaffeinated and of two types of coffee substitutes based on barley and chicory. The following physical-chemical characteristics were performed: moisture, pH, content of polyphenols and qualitatively determination of caffeine, by thin-layer chromatography. The moisture of the investigated coffee and substitutes of coffee was in the range 1,5 and 3,6%. By analyzing the moisture of the coffee substitutes, we observed that coffee based on barley has the highest moisture and chicory has the lowest value. The caffeine was qualitatively determined by thin-layer chromatography. It was found that all types of the investigated samples contain caffeine excepting decaffeinated coffee. Polyphenols content of the analysed coffee samples varied in the range of 2.8-3.2 mg/g.


2006 ◽  
Vol 46 (5) ◽  
pp. 2030-2042 ◽  
Author(s):  
Luca Bernazzani ◽  
Celia Duce ◽  
Alessio Micheli ◽  
Vincenzo Mollica ◽  
Alessandro Sperduti ◽  
...  

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Abdul Rauf ◽  
Saba Maqbool ◽  
Muhammad Naeem ◽  
Adnan Aslam ◽  
Hamideh Aram ◽  
...  

Vanadium is a biologically active product with significant industrial and biological applications. Vanadium is found in a variety of minerals and fossil fuels, the most common of which are sandstones, crude oil, and coal. Topological descriptors are numerical numbers assigned to the molecular structures and have the ability to predict certain of their physical/chemical properties. In this paper, we have studied topological descriptors of vanadium carbide structure based on ev and ve degrees. In particular, we have computed the closed forms of Zagreb, Randic, geometric-arithmetic, and atom-bond connectivity (ABC) indices of vanadium carbide structure based on ev and ve degrees. This kind of study may be useful for understanding the biological and chemical behavior of the structure.


Author(s):  
Mohammad Reza Farahani

Let G be a molecular graph, a topological index is a numeric quantity related to G which is invariant under graph automorphisms. The eccentric connectivity index ξ(G) is defined as ξ(G) = ∑vV(G) d x ε(v) where dv, ε(v) denote the degree of vertex v in G and the largest distance between vand any other vertex u of G. The connective eccentric index of graph G is defined as Cξ(G) = ∑vV(G) dv /ε(v) In the present paper we compute the connective eccentric index of CircumcoroneneHomologous Series of Benzenoid Hk (k ≥ 1).


2001 ◽  
Vol 66 (9) ◽  
pp. 605-611 ◽  
Author(s):  
Ivan Gutman ◽  
Mirko Lepovic

Let ?v denote the degree of the vertex v of a molecular graph G. Then the connectivity index of G is defined as C (?) = G (?,C) = ? (?u?v)?, where the summation goes over all pairs of adjacent vertices. The exponent ? is usually chosen to be equal to -1/2, but other options were considered as well, especially ?=-1. We show that whereas C(-1/2) is a suitable measure of branching of the carbon-atom skeleton of organic molecules, and thus applicable as a topological index for modeling physico-chemical properties of the respective compounds, this is not the case with C(-1). The value of ? is established, beyond which C(?) fails to correctly reflect molecular branching.


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