scholarly journals The Vertex Version of Weighted Wiener Number for Bicyclic Molecular Structures

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Wei Gao ◽  
Weifan Wang
Keyword(s):  
Melting Point ◽  
Structural Analysis ◽  
Boiling Point ◽  
Molecular Graph ◽  
Chemical Compounds ◽  
Molecular Structures ◽  
Strongly Correlated ◽  
Compound A ◽  
Wiener Number ◽  
Theoretical Results

Graphs are used to model chemical compounds and drugs. In the graphs, each vertex represents an atom of molecule and edges between the corresponding vertices are used to represent covalent bounds between atoms. We call such a graph, which is derived from a chemical compound, a molecular graph. Evidence shows that the vertex-weighted Wiener number, which is defined over this molecular graph, is strongly correlated to both the melting point and boiling point of the compounds. In this paper, we report the extremal vertex-weighted Wiener number of bicyclic molecular graph in terms of molecular structural analysis and graph transformations. The promising prospects of the application for the chemical and pharmacy engineering are illustrated by theoretical results achieved in this paper.

scholarly journals Eccentricity based topological indices of siloxane and POPAM dendrimers

2020 ◽  
Vol 43 (1) ◽  
pp. 92-98
Author(s):  
Muhammad Azhar Iqbal ◽  
Muhammad Imran ◽  
Muhammad Asad Zaighum
Keyword(s):  
Molecular Graph ◽  
Chemical Compounds ◽  
Topological Indices ◽  
Molecular Structures ◽  
Topological Descriptors ◽  
Physico Chemical ◽  
Early Drug

AbstractA massive of early drug tests indicates that there is some strong inner connections among the bio-medical and pharmacology properties of nanostar dendrimers and their molecular structures. Topological descriptors are presented as fundamentally transforming a molecular graph into a number. There exist various categories of such descriptors particularly those descriptors that based on edge and vertex distances. Topological descriptors are exercised for designing biological, physico-chemical, toxicological, pharmacologic and other characteristics of chemical compounds. In this paper, we study infinite classes of siloxane and POPAM dendrimers and derive their Zagreb eccentricity indices, eccentric-connectivity and total-eccentricity indices.

scholarly journals Locating and Multiplicative Locating Indices of Graphs with QSPR Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Suha Wazzan ◽  
Anwar Saleh
Keyword(s):  
Melting Point ◽  
Linear Regression ◽  
Boiling Point ◽  
Chemical Compounds ◽  
Chemical Characteristics ◽  
Physico Chemical

In this paper, by introducing a new version of locating indices called multiplicative locating indices, we compute exact values of these indices on well-known families of graphs and graphs obtained by some operations. Also, we determine the importance of locating and multiplicative locating indices of hexane and its isomers. Furthermore, we show that locating indices actually have a reasonable correlation using linear regression with physico-chemical characteristics such as enthalpy, melting point, and boiling point. This approximation can be extended into several chemical compounds.

scholarly journals Computing Bounds for General Randic Coindex of Sum Graphs

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Muhammad Javaid ◽  
Muhammad Ibraheem ◽  
Ebenezer Bonyah
Keyword(s):  
Molecular Structure ◽  
Surface Tension ◽  
Graph Theory ◽  
Melting Point ◽  
Structural Properties ◽  
Boiling Point ◽  
Topological Index ◽  
Molecular Structures ◽  
Mathematical Formula ◽  
Numerical Table

The physical and structural properties of molecular structure or graph such as boiling point, melting point, surface tension, or solubility are studied using topological index (TI). Topological index is a mathematical formula that can be applied to any graph which models some molecular structures. The various operations play an important role in graph theory such as joining, union, intersection, products, and subdivision. In this paper, we computed the bounds for general Randic coindex of F -sum graphs such as ( S -sum, R -sum, Q -sum, and T -sum) in the form of their factor graphs. At the end, results are illustrated by numerical table for the particular F -sum graphs.

scholarly journals Cube-Rhombellane Related Structures: A Drug Perspective

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2533 ◽  
Author(s):  
Mircea Vasile Diudea ◽  
Claudiu Nicolae Lungu ◽  
Csaba Levente Nagy
Keyword(s):  
Single Point ◽  
Molecular Graph ◽  
Molecular Structures ◽  
Combinatorial Synthesis ◽  
Stability Evaluation ◽  
New Class ◽  
Physico Chemical ◽  
Molecular Stability ◽  
Internal Mobility ◽  
Point Data

Rhombellanes represent a new class of structures, of which homeomorphs may be synthesized as real molecules. Cube-rhombellane is a double-shell structure, with vertices of degree 3 and 6, respectively. Several hypothetical structures/molecules were proposed and computed using molecular graph theory and coordination chemistry principles. Some geometries were optimized at the B3LYP/6-31G (d, p) level of theory, followed by harmonic vibrational frequency analysis at the same level of theory, single point data were collected in view of molecular stability evaluation. Some of the bioactive functionalized structures were also proposed and explored by molecular mechanics (MM)-based conformational analysis, to check their internal mobility. Drug-like properties of the proposed molecular structures were compared with some existing nano-molecules (fullerenes, nanotubes). ADME and other physico-chemical characteristics were computed using commercial software. Substructures of the proposed molecules, useful in a future synthesis, were provided by retro combinatorial synthesis (RECAP). Computational results obtained are promising regarding ADME properties, drug-likeness and nano-properties.

XXXI.—Precipitated Sulphur

1907 ◽  
Vol 27 ◽  
pp. 308-311 ◽  
Author(s):  
Alexander Smith ◽  
R. H. Brownlee
Keyword(s):  
Melting Point ◽  
Boiling Point ◽  
Pale Yellow ◽  
The Subject ◽  
Distinct Variety ◽  
Mobile Liquid

AbstractIn papers previously read before the Society, the behaviour of sulphur when heated has been the subject of investigation. It has been shown that the transition from a pale-yellow mobile liquid to a deep-brown viscous one, which occurs as the temperature rises in the neighbourhood of 160°, is due to the production from the mobile sulphur (Sλ) of another distinct variety (Sμ). The proportion of the viscous variety (Sμ) is about 4 per cent, at the melting point (114·5°). At 160° it has become 11 per cent., at 170° 19 per cent., and at the boiling point 34 per cent.

scholarly journals Dzyaloshinskii–Moriya Coupling in 3d Insulators

2019 ◽  
Vol 4 (4) ◽  
pp. 84 ◽  
Author(s):  
Alexander Moskvin
Keyword(s):  
Density Functional ◽  
Microscopic Theory ◽  
Strongly Correlated ◽  
Spin Orbital ◽  
Functional Theory ◽  
Different Types ◽  
Theoretical Results ◽  
Spin Orbital Coupling ◽  
Density Transfer ◽  
Super Exchange Interaction

We present an overview of the microscopic theory of the Dzyaloshinskii–Moriya (DM) coupling in strongly correlated 3d compounds. Most attention in the paper centers around the derivation of the Dzyaloshinskii vector, its value, orientation, and sense (sign) under different types of the (super)exchange interaction and crystal field. We consider both the Moriya mechanism of the antisymmetric interaction and novel contributions, in particular, that of spin–orbital coupling on the intermediate ligand ions. We have predicted a novel magnetic phenomenon, weak ferrimagnetism in mixed weak ferromagnets with competing signs of Dzyaloshinskii vectors. We revisit a problem of the DM coupling for a single bond in cuprates specifying the local spin–orbital contributions to the Dzyaloshinskii vector focusing on the oxygen term. We predict a novel puzzling effect of the on-site staggered spin polarization to be a result of the on-site spin–orbital coupling and the cation-ligand spin density transfer. The intermediate ligand nuclear magnetic resonance (NMR) measurements are shown to be an effective tool to inspect the effects of the DM coupling in an external magnetic field. We predict the effect of a strong oxygen-weak antiferromagnetism in edge-shared CuO 2 chains due to uncompensated oxygen Dzyaloshinskii vectors. We revisit the effects of symmetric spin anisotropy directly induced by the DM coupling. A critical analysis will be given of different approaches to exchange-relativistic coupling based on the cluster and the DFT (density functional theory) based calculations. Theoretical results are applied to different classes of 3d compounds from conventional weak ferromagnets ( α -Fe 2 O 3 , FeBO 3 , FeF 3 , RFeO 3 , RCrO 3 , ...) to unconventional systems such as weak ferrimagnets (e.g., RFe 1 - x Cr x O 3 ), helimagnets (e.g., CsCuCl 3 ), and parent cuprates (La 2 CuO 4 , ...).

scholarly journals Some Eccentricity-Based Topological Indices and Polynomials of Poly(EThyleneAmidoAmine) (PETAA) Dendrimers

Processes ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 433 ◽  
Author(s):  
Jialin Zheng ◽  
Zahid Iqbal ◽  
Asfand Fahad ◽  
Asim Zafar ◽  
Adnan Aslam ◽  
...  
Keyword(s):  
Molecular Descriptors ◽  
Molecular Graph ◽  
Topological Indices ◽  
Molecular Structures ◽  
Connectivity Index ◽  
Connectivity Indices ◽  
Numerical Invariants ◽  
Explicit Representations ◽  
Pharmaceutical Properties

Topological indices have been computed for various molecular structures over many years. These are numerical invariants associated with molecular structures and are helpful in featuring many properties. Among these molecular descriptors, the eccentricity connectivity index has a dynamic role due to its ability of estimating pharmaceutical properties. In this article, eccentric connectivity, total eccentricity connectivity, augmented eccentric connectivity, first Zagreb eccentricity, modified eccentric connectivity, second Zagreb eccentricity, and the edge version of eccentric connectivity indices, are computed for the molecular graph of a PolyEThyleneAmidoAmine (PETAA) dendrimer. Moreover, the explicit representations of the polynomials associated with some of these indices are also computed.

scholarly journals Topological indices of rhombus type silicate and oxide networks

2017 ◽  
Vol 95 (2) ◽  
pp. 134-143 ◽  
Author(s):  
M. Javaid ◽  
Masood Ur Rehman ◽  
Jinde Cao
Keyword(s):  
Molecular Graph ◽  
Chemical Compounds ◽  
Quantitative Structure Activity Relationship ◽  
Topological Indices ◽  
Quantitative Structure ◽  
Structure Property ◽  
Structure Activity ◽  
Structure Property Relationship ◽  
Cartesian Coordinate ◽  
Atom Bond

For a molecular graph, a numeric quantity that characterizes the whole structure of a graph is called a topological index. In the studies of quantitative structure – activity relationship (QSAR) and quantitative structure – property relationship (QSPR), topological indices are utilized to guess the bioactivity of chemical compounds. In this paper, we compute general Randić, first general Zagreb, generalized Zagreb, multiplicative Zagreb, atom-bond connectivity (ABC), and geometric arithmetic (GA) indices for the rhombus silicate and rhombus oxide networks. In addition, we also compute the latest developed topological indices such as the fourth version of ABC (ABC4), the fifth version of GA (GA5), augmented Zagreb, and Sanskruti indices for the foresaid networks. At the end, a comparison between all the indices is included, and the result is shown with the help of a Cartesian coordinate system.

Stereochemistry of serotonin receptor ligands from crystallographic data. Crystal structures of NAN-190.HBr, 1-phenylbiguanide, MDL 72222 and mianserin.HCl and selectivity criteria towards 5-HT1, 5-HT2 and 5-HT3 receptor subtypes

1996 ◽  
Vol 52 (3) ◽  
pp. 509-518 ◽  
Author(s):  
A. Dalpiaz ◽  
V. Ferretti ◽  
P. Gilli ◽  
V. Bertolasi
Keyword(s):  
Structural Analysis ◽  
Serotonin Receptor ◽  
Molecular Structures ◽  
Receptor Subtypes ◽  
Receptor Ligands ◽  
Endogenous Ligand ◽  
Constant Length ◽  
Mdl 72222 ◽  
Crystal And Molecular Structures ◽  
Pharmacophoric Feature

The crystal and molecular structures of the following serotoninergic drugs have been determined: (1) 1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl]piperazine hydrobromide hemihydrate (NAN-190.HBr), C23H28N3O3 +.Br−.1/2H2O, Mr = 483.42, monoclinic, C2/c, a = 21.916 (4), b = 15.207 (2), c = 14.052 (2) Å, β = 101.56 (1)°, V = 4588 (1) Å3, Z = 8, Dx = 1.40 Mg m−3, λ(Mo Kα) = 0.71069 Å, μ = 1.823 mm−1, F(000) = 2008, T = 295 K, R = 0.035 for 2617 observed reflections; (2) N-phenylimidocarbonimidic diamide (1-phenylbiguanide), C8H11N5, Mr = 177.21, monoclinic, P21/c, a = 9.781 (2), b = 35.040 (5), c = 11.000 (2) Å, β = 97.72 (1)°, V = 3736 (1) Å3, Z = 16, Dx = 1.26 Mg m−3, λ(Mo Kα) = 0.71069 Å, μ= 0.084 mm−1, F(000) = 1504, T = 295 K, R = 0.070 for 3407 observed reflections; (3) 8-methyl-8-azabicyclo[3.2.1.]oct-3-yl 3,5-dichlorobenzoate (MDL 72222), C15H17C12NO2, Mr = 314.21, triclinic, P{\bar 1}, a = 8.480 (3), b = 9.840 (3), c = 10.15 (4) Å, α = 90.04 (3), β = 111.77 (3), γ = 105.07 (3)°, V = 755.6 (5) Å3, Z = 2, Dx = 1.38 Mg m−3, λ(Mo Kα) = 0.71069 Å, μ = 0.430 mm−1, F(000) = 328, T = 295 K, R = 0.070 for 1685 observed reflections; (4) 1,2,3,4,10,14b-hexahydro-2-methyldibenzo[cf]pyrizino[1,2-a]azepine hydrochloride (mianserin.HCl), C18H21N2 +.Cl−, Mr = 300.83, monoclinic, P21/a, a = 9.014 (2), b = 14.917 (2), c = 12.412 (2) Å, β = 108.84 (1)°, V = 1579.5 (5) Å3, Z = 4, Dx = 1.26 Mg m−3, λ(Mo Kα) = 0.71069 Å, μ = 0.237 mm−1, F(000) = 640, T = 295 K, R = 0.063 for 1493 observed reflections. A systematic structural analysis of the present compounds and others known to interact with the 5-HT1, 5-HT2 and 5-HT3 receptors allows to identify their similarities with the endogenous ligand serotonin (5-HT) and the stereochemical differences which determine selectivity for the various receptor subtypes. The pharmacophoric feature for 5-HT receptor binding is identified in a constant-length vector linking an aromatic ring with a protonated nitrogen, while specific affinities for receptorial subtypes and the nature of the effect appear to be modulated by the dimensions of the substituents at nitrogen.

LIGHT-INDUCED MODIFICATION OF KINETIC MOLECULAR PROPERTIES: ENHANCEMENT OF OPTICAL KERR EFFECT IN ABSORBING LIQUIDS, PHOTOINDUCED TORQUE AND MOLECULAR MOTORS IN DYE-DOPED NEMATICS

2000 ◽  
Vol 09 (02) ◽  
pp. 157-182 ◽  
Author(s):  
M. KREUZER ◽  
L. MARRUCCI ◽  
D. PAPARO
Keyword(s):  
Liquid Crystals ◽  
Molecular Motors ◽  
Kerr Effect ◽  
Optical Nonlinearity ◽  
Molecular Structures ◽  
Molecular Properties ◽  
Main Role ◽  
Theoretical Results ◽  
Insight Into ◽  
Dye Molecule

In this paper we review some experimental and theoretical results on the enhancement of orientational optical nonlinearities observed in dye-doped liquids and liquid crystals. We argue that this enhancement is derived from a photoinduced modification of kinetic molecular properties. Moreover we highlight an analogy between the mechanism of this effect in nematic liquid crystals and the working principles of "molecular motors". This analogy helps us to refine the understanding of this effect and to identify the molecular parameters which play the main role. Finally we review some recent experimental results about the dependence of the optical nonlinearity enhancement on the detailed dye and host molecular structures. These results provide some insight into the light-induced phenomena taking place inside a dye molecule.

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