An Index of Molecular Flexibility from Kappa Shape Attributes

Abstract

An index encoding the structural attribute known as flexibility has been devised based upon the chemical graph. The flexibility definition is based upon the role of molecular size, branching, cycles and heteroatom content. The calculation of the index, phi, uses information from the kappa indexes to encode these contributions. The flexibility index is made equal to the product of kappa‐one and kappa‐two, normalized to the number of atoms in the graph. Examples reveal the structure‐activity potential for the index.

Evaluation of descriptors and classification schemes to predict cytochrome substrates in terms of chemical information

“…For this study, we used topological descriptors that can be calculated using low-cost software that runs on the desktop. Thus, we used the original Kier and Hall chi, valence chi (v v ), kappa shape (j) and E-state (S) indices [41][42][43][44]. In selecting the specific descriptors for the classification analysis, each descriptor had to have a value for at least a third of the molecules.…”

Mold2Molecular Descriptors for QSAR

“…The Kier index [46][47][48][49] encodes the chemical structure flexibility, which depends on molecule size, branching, cycles, and heteroatom content. The flexibility index is made equal to the product of the kappa-one and kappa-two modified shape descriptors normalized to the number of atoms in the H-depleted molecular graph.…”

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“…Traditional topological descriptors [120][121][122] include molecular connectivity indices [123,124], shape and flexibility indices [125,126], topological indices [127,128], and electrotopological state indices [74]. Topological descriptors are counts of number of atoms, bonds, branching and electrons that are related to the fundamental quantities that determine properties [100,129].…”