Untitled

Abstract

Since the dawn of quantitative structure-properties relationships (QSPR), empirical parameters related to structural, electronic and hydrophobic molecular properties have been used as molecular descriptors to determine such relationships. Among all these parameters, Hammett sigma constants and the logarithm of the octanol-water partition coefficient, log P, have been massively employed in QSPR studies. In the present paper, a new molecular descriptor, based on quantum similarity measures (QSM), is proposed as a general substitute of these empirical parameters. This work continues previous analyses related to the use of QSM to QSPR, introducing molecular quantum self-similarity measures (MQS-SM) as a single working parameter in some cases. The use of MQS-SM as a molecular descriptor is first confirmed from the correlation with the aforementioned empirical parameters. The Hammett equation has been examined using MQS-SM for a series of substituted carboxylic acids. Then, for a series of aliphatic alcohols and acetic acid esters, log P values have been correlated with the self-similarity measure between density functions in water and octanol of a given molecule. And finally, some examples and applications of MQS-SM to determine QSAR are presented. In all studied cases MQS-SM appeared to be excellent molecular descriptors usable in general QSPR applications of chemical interest.

Notes on quantitative structure‐properties relationships (QSPR) part 2: The role of the number of atoms as a molecular descriptor

“…This fact has been empirically proved in several molecular sets, as shown in references, [40][41][42][43][44][45][46][47][48] where a number of diverse problems, connected with this substitutive quantum representation have been studied several years ago. Thus, in many instances there is more advisable to construct models with quantum selfsimilarities than simplified forms of them, like the present discussed molecular description, ending with number of atoms as a descriptor.…”

“…This kind of simplification of the fundamental QQSPR equations has been formerly tested in many application examples. [39][40][41][42][43][44][45][46][47][48][49] Due that one can consider the second term in eq. (14) almost a constant in a homogeneous CS fundamental QQSPR treatment, that is:…”

Chapter 6. Quantum Chemical Topology: on Descriptors, Potentials and Fragments

“…It has been shown in the first PLS study 68 that the locus of action in benzoic acids may be recovered. Hence, a priori knowledge of a centre of action for any given activity is unnecessary 70 with QTMS. Variable importance in the projection (VIP) values 71 may also be employed.…”

Metrics for measuring distances in configuration spaces

“…Diversity analysis is at the heart of any structure prediction method in material science and solid state physics [1][2][3][4][5] and conformer search in structural biology and drug discovery. [6][7][8][9][10][11][12] In the latter case, most of the proposed approaches [13][14][15] use approximate methods that reduce the structure description information, e.g. by excluding the side chains in a protein or a two dimensional representations of the molecule, [16] to speed up the searching procedure.…”