Molecular connectivity indices revisited

1990 ◽  
Vol 55 (3) ◽  
pp. 630-633 ◽  
Author(s):  
Milan Kunz
Keyword(s):  
Adjacency Matrix ◽  
Connectivity Index ◽  
Regular Graphs ◽  
Randić Index ◽  
Molecular Connectivity ◽  
Randic Index ◽  
Molecular Connectivity Indices ◽  
Connectivity Indices

It is shown that the product νiνj of degrees ν of vertices ij, incident with the edge ij, is the number of paths of length 1, 2, and 3 in which the edge is in the center. The unified connectivity index χm = Σ(νiνj)m, where the sum is made over all edges, with m = 1, is the sum of the number of edges, the Platt number and the polarity number. And it is identical with the half sum of the cube A3 of the adjacency matrix A. The Randić index χ-1/2 of regular graphs does not depend on their connectivity.

scholarly journals Ordering of alkane isomers by means of connectivity indices

2002 ◽  
Vol 67 (2) ◽  
pp. 87-97 ◽  
Author(s):  
Ivan Gutman ◽  
Dusica Vidovic ◽  
Anka Nedic
Keyword(s):  
Carbon Atom ◽  
Organic Molecule ◽  
Molecular Graph ◽  
Connectivity Index ◽  
Randić Index ◽  
Randic Index ◽  
Connectivity Indices ◽  
The Difference

The connectivity index of an organic molecule whose molecular graph is Gis defined as C(?)=?(?u?v)??where ?u is the degree of the vertex u in G, where the summation goes over all pairs of adjacent vertices of G and where ? is a pertinently chosen exponent. The usual value of ? is ?1/2, in which case ?=C(?1/2) is referred to as the Randic index. The ordering of isomeric alkanes according to ??follows the extent of branching of the carbon-atom skeleton. We now study the ordering of the constitutional isomers of alkanes with 6 through 10 carbon atoms with respect to C(?) for various values of the parameter ?. This ordering significantly depends on ?. The difference between the orderings with respect to ??and with respect to C(?) is measured by a function ??and the ?-dependence of ??was established.

Inhibition of Hill Reaction by 2-Azido-s-triazine Derivatives: QSAR Study with Molecular Connectivity Indices

1989 ◽  
Vol 44 (3-4) ◽  
pp. 255-261 ◽  
Author(s):  
Milan Š Šoškić ◽  
Aleksandar Sabljić
Keyword(s):  
Structural Features ◽  
Second Order ◽  
Fine Tuning ◽  
Superior Performance ◽  
Hill Reaction ◽  
Retention Data ◽  
Molecular Connectivity ◽  
Inhibitory Potency ◽  
Molecular Connectivity Indices ◽  
Connectivity Indices

Abstract 2-A zido-s-T riazines, Connectivity Indices. Inhibition of Hill Reaction. Photosystem II, OSAR Modelling This study was undertaken to find a simple and accurate structural parameters for the quantita­tive description of inhibitory potency of 2-azido-s-triazines in Hill reaction and to gain more information about the mechanism of inhibition on molecular level. A very good correlation (r = 0.946) was obtained between the pl50 values (the negative logarithm of the molar concentra­tion that causes 50% inhibition) and the valence zero-order and the difference between the second-order and the valence second-order molecular connectivity indices. This model, when com pared with the empirical models based on the 1-octano/water partition coefficients and the chromatographic retention data, shows superior performance in accuracy and range of applicabili­ty. In addition, the direct correspondence between molecular structure and above connectivity indices makes it possible to locate structural features responsible for the inhibitory potency of 2-azido-s-triazines in Hill reaction. From our OSAR analysis, the interaction between the chloro­plast receptor site and 2-azido-s-triazines, which causes inhibition of Hill reaction, is primarily influenced by the size of alkylamino substituents and it accounts for the most variation in the pl50 data. The structural features of secondary importance that control the magnitude of pl50’s are the polarity of alkylamino chains and the degree of branching on alpha carbon atom of R:alkylamino substituent. Com pared with the main factor, the size of alkylamino substituents, they can be viewed as a fine tuning elements for the inhibitory potency of 2-azido-s-triazines.

Internal Pressure and Molecular Connectivity Indices for Alkanes

1998 ◽  
Vol 14 (05) ◽  
pp. 407-412
Author(s):  
Zhang Guo-Zheng ◽  
◽  
Ying Xu-Gen ◽  
Liu Guo-Jie
Keyword(s):  
Internal Pressure ◽  
Molecular Connectivity ◽  
Molecular Connectivity Indices ◽  
Connectivity Indices

Research on Calculation of Molecular Connectivity Index

2013 ◽  
Vol 303-306 ◽  
pp. 2671-2674 ◽  
Author(s):  
Wei Ye Tao ◽  
Lai You Wang ◽  
Guo Quan Huang ◽  
Hua Ying Zhou ◽  
Man Luo
Keyword(s):  
Adjacency Matrix ◽  
Molecular Descriptor ◽  
Connectivity Index ◽  
Molecular Connectivity ◽  
Molecular Connectivity Index ◽  
Ascii File ◽  
Structural Selectivity ◽  
2D And 3D ◽  
3D Topology ◽  
Mol2 Format

Compared to other topological indices, molecular connectivity index has good structural selectivity and correlation.According to the molecule’s 2D and 3D topology file, we conducted research on the mol2 format file to consider how to convert the ASCII file into the adjacency matrix. Based on the adjacency matrix, we analyzed the relevant algorithm to calculate the molecules’ molecular connectivity index through adjacency matrix. As a molecular descriptor, the molecular connectivity index can be used in QSAR.

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