3D-Modelling and Prediction by Whim Descriptors. Part 7. Physico-Chemical Properties of Haloaromatics: Comparison Between Whim and Topological Descriptors

1997 ◽  
Vol 7 (1-4) ◽  
pp. 133-150 ◽  
Author(s):  
C. Chiorboli ◽  
P. Gramatica ◽  
R. Piazza ◽  
A. Pino ◽  
R. Todeschini
Keyword(s):  
Chemical Properties ◽  
3D Modelling ◽  
Topological Descriptors ◽  
Physico Chemical

scholarly journals A new approach in topological descriptors usage. Iterated line graphs in the theoretical prediction of physico-chemical properties of saturated hydrocarbons

2019 ◽  
Keyword(s):  
Boiling Point ◽  
Molecular Graph ◽  
Chemical Properties ◽  
Topological Descriptors ◽  
Vaporization Enthalpy ◽  
Line Graphs ◽  
Regression Equations ◽  
Saturated Hydrocarbons ◽  
Program Complex ◽  
Physico Chemical

A new look on the problem of the molecular systems index description is presented. The capabilities of iterated line (edge) graphs in characterization of saturated hydrocarbons properties were investigated. It was demonstrated that single selected molecular (graph-theoretical (topological) or informational) descriptor calculated for the sequence of nested line graphs provides quite reliable progressive set of regression equations. Hence, the problem of descriptor set reduction is solved in the presented approach at list partially. Corresponding program complex (QUASAR) has been implemented with Python 3 program language. As the test example physico-chemical properties of octane isomers have been chosen. Among the properties under investigation there are boiling point, critical temperature, critical pressure, enthalpy of vaporization, enthalpy of formation, surface tension and viscosity. The corresponding rather simple linear regression equations which include one, two or three parameters correspondingly have been obtained. The predictive ability of the equations has been investigated using internal validation tests. The test by leave-one-out (LOO) validation and Y‑scrambling evaluate the obtained equations as adequate. For instance, for the regression model for boiling point the best equation characterizes by determination coefficients R2 = 0.943, with LOO procedure – Q2 = 0.918, while for the Y-scrambling test Q2y-scr<0.3 basically. It is shown that all the abovementioned molecular properties in iterated line graph approach can be effectively described by commonly used topological indices. Namely almost every randomly selected topological index can give adequate equation. Effectiveness is demonstrated on the example of Zagreb group indices. Also essential effectiveness and rather universal applicability of the so-called “forgotten” index (ZM3) was demonstrated.

Polynomials of Degree-Based Indices of Metal-Organic Networks

2020 ◽  
Vol 23 ◽  
Author(s):  
Ali Ahmad ◽  
Muhammad Ahsan Asim ◽  
Muhammad Faisal Nadeem
Keyword(s):  
Metal Ion ◽  
Chemical Properties ◽  
Molecular Structures ◽  
Topological Descriptors ◽  
Molecular Compound ◽  
Super Capacitor ◽  
Physico Chemical ◽  
Metal Organic ◽  
Carbon Based ◽  
Organic Networks

Aim and Objective: Metal-organic network (MON) is a special class of molecular compounds comprising of groups or metal ion and carbon-based ligand. These chemical compounds are examined employing one, two- or threedimensional formation of porous ore and subfamilies of polymers. Metal-organic networks are frequently utilized in catalysis for the parting & distillation of different gases and by means of conducting solid or super-capacitor. In various scenarios, the compounds are observed balanced in the procedure of deletion or diluter of the molecule and can be rebuilt with another molecular compound. The physical solidity and mechanical characteristics of the metal-organic network have attained great attention due to the mention properties. This study was undertaken to find the polynomials of MON. Methods: Topological descriptor is a numerical number that is utilized to predict the natural correlation amongst the physico-chemical properties of the molecular structures in their elementary networks. Results: After partitioning the vertices based on their degrees, we calculate different degree-based topological polynomials for two distinct metal-organic networks with an escalating number of layers containing both metals and carbon-based ligand vertices. Conclusion: In the analysis of the metal-organic network, topological descriptors and their polynomials play an important part in modern chemistry. An analysis between the calculated various forms of the polynomials and topological descriptors through the numeric values and their graphs is also comprised.

scholarly journals Harmonic Index and Zagreb Indices of Vertex-Semitotal Graphs

2020 ◽  
Vol 13 (5) ◽  
pp. 1260-1269
Author(s):  
Aysun Yurttas Gunes ◽  
Muge Togan ◽  
Musa Demirci ◽  
Ismail Naci Cangul
Keyword(s):  
Graph Theory ◽  
Chemical Properties ◽  
Spectral Graph Theory ◽  
Molecular Structures ◽  
Topological Descriptors ◽  
Graph Invariant ◽  
Qsar Studies ◽  
Spectral Graph ◽  
Graph Classes ◽  
Physico Chemical

Graph theory is one of the rising areas in mathematics due to its applications in many areas of science. Amongst several study areas in graph theory, spectral graph theory and topological descriptors are in front rows. These descriptors are widely used in QSPR/QSAR studies in mathematical chemistry. Vertex-semitotal graphs are one of the derived graph classes which are useful in calculating several physico-chemical properties of molecular structures by means of molecular graphs modelling the molecules. In this paper, several topological descriptors of vertex-semitotal graphs are calculated. Some new relations on these values are obtained by means of a recently defined graph invariant called omega invariant.

scholarly journals On Distance-Based Topological Descriptors of Chemical Interconnection Networks

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Min Hu ◽  
Haidar Ali ◽  
Muhammad Ahsan Binyamin ◽  
Bilal Ali ◽  
Jia-Bao Liu ◽  
...  
Keyword(s):  
Interconnection Networks ◽  
Topological Index ◽  
Chemical Properties ◽  
Topological Descriptors ◽  
Silicate Network ◽  
Pi Index ◽  
Szeged Index ◽  
Physico Chemical ◽  
Chain Silicate ◽  
First Time

Structure-based topological descriptors of chemical networks enable us the prediction of physico-chemical properties and the bioactivities of compounds through QSAR/QSPR methods. Topological indices are the numerical values to represent a graph which characterises the graph. One of the latest distance-based topological index is the Mostar index. In this paper, we study the Mostar index, Szeged index, PI index, ABC GG index, and NGG index, for chain oxide network COX n , chain silicate network CS n , ortho chain S n , and para chain Q n , for the first time. Moreover, analytically closed formulae for these structures are determined.

Computing topological polynomials of mesh-derived networks

2018 ◽  
Vol 10 (06) ◽  
pp. 1850077 ◽  
Author(s):  
Muhammad Imran ◽  
Abdul Qudair Baig ◽  
Shafiq Ur Rehman ◽  
Haidar Ali ◽  
Roslan Hasni
Keyword(s):  
Mesh Networks ◽  
Molecular Graph ◽  
Chemical Properties ◽  
Chemical Compounds ◽  
Topological Descriptors ◽  
Cut Edge ◽  
Physico Chemical ◽  
First Time ◽  
Ga Index ◽  
Atom Bond

Topological descriptors are numerical parameters of a molecular graph which characterize its molecular topology and are usually graph invariant. In QSAR/QSPR study, physico-chemical properties and topological indices such as Randić, atom-bond connectivity [Formula: see text] and geometric-arithmetic (GA) index are used to predict the bioactivity of chemical compounds. Graph theory has found a considerable use in this area of research. The counting polynomials are those polynomials having at exponent the extent of a property partition and coefficients the multiplicity/occurrence of the corresponding partition. All of the studied interconnection mesh networks in this paper are motivated by the molecular structure of a Sodium chloride NaCl. In this paper, Omega, Sadhana and PI polynomials are computed for mesh-derived networks. These polynomials were proposed on the ground of quasi-orthogonal cut edge strips in polycyclic graphs. These polynomials count equidistant and non-equidistant edges in graphs. Moreover, the analytical closed formulas of these polynomials for mesh-derived networks are computed for the first time.

Decoration of specific sites on freeze-fractured membranes

1978 ◽  
Vol 36 (2) ◽  
pp. 140-141
Author(s):  
H. Gross ◽  
H. Moor
Keyword(s):  
Pure Water ◽  
Freeze Fracture ◽  
Chemical Properties ◽  
Surface Forces ◽  
Sulfate Pentahydrate ◽  
Copper Sulfate Pentahydrate ◽  
Physico Chemical ◽  
Water Of Hydration ◽  
Small Container ◽  
Binding Forces

Fracturing under ultrahigh vacuum (UHV, p ≤ 10-9 Torr) produces membrane fracture faces devoid of contamination. Such clean surfaces are a prerequisite foe studies of interactions between condensing molecules is possible and surface forces are unequally distributed, the condensate will accumulate at places with high binding forces; crystallites will arise which may be useful a probes for surface sites with specific physico-chemical properties. Specific “decoration” with crystallites can be achieved nby exposing membrane fracture faces to water vopour. A device was developed which enables the production of pure water vapour and the controlled variation of its partial pressure in an UHV freeze-fracture apparatus (Fig.1a). Under vaccum (≤ 10-3 Torr), small container filled with copper-sulfate-pentahydrate is heated with a heating coil, with the temperature controlled by means of a thermocouple. The water of hydration thereby released enters a storage vessel.

Physico-Chemical Properties of Recombinant Desulphatohirudin

1990 ◽  
Vol 63 (03) ◽  
pp. 499-504 ◽  
Author(s):  
A Electricwala ◽  
L Irons ◽  
R Wait ◽  
R J G Carr ◽  
R J Ling ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Gel Filtration ◽  
Chemical Properties ◽  
Alpha Helix ◽  
Apparent Molecular Weight ◽  
Correlation Spectroscopy ◽  
Nmr Studies ◽  
Recombinant Hirudin ◽  
Physico Chemical ◽  
Recombinant Molecule

SummaryPhysico-chemical properties of recombinant desulphatohirudin expressed in yeast (CIBA GEIGY code No. CGP 39393) were reinvestigated. As previously reported for natural hirudin, the recombinant molecule exhibited abnormal behaviour by gel filtration with an apparent molecular weight greater than that based on the primary structure. However, molecular weight estimation by SDS gel electrophoresis, FAB-mass spectrometry and Photon Correlation Spectroscopy were in agreement with the theoretical molecular weight, with little suggestion of dimer or aggregate formation. Circular dichroism studies of the recombinant molecule show similar spectra at different pH values but are markedly different from that reported by Konno et al. (13) for a natural hirudin-variant. Our CD studies indicate the presence of about 60% beta sheet and the absence of alpha helix in the secondary structure of recombinant hirudin, in agreement with the conformation determined by NMR studies (17)

Physico-chemical properties of the rare-earth metals, scandium, and yttrium

1963 ◽  
Vol 79 (2) ◽  
pp. 263-293 ◽  
Author(s):  
E.M. Savitskii ◽  
V.F. Terekhova ◽  
O.P. Naumkin
Keyword(s):  
Rare Earth ◽  
Rare Earth Metals ◽  
Chemical Properties ◽  
Physico Chemical ◽  
The Rare Earth
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