Revision and Extension of a Generally Applicable Group Additivity Method for the Calculation of the Refractivity and Polarizability of Organic Molecules at 298.15 K

Abstract

In a continuation and extension of an earlier publication, the calculation of the refractivity and polarizability of organic molecules at standard conditions is presented, applying a commonly applicable computer algorithm based on an atom group additivity method, where the molecules are broken down into their constituting atoms, these again being further characterized by their immediate neighbor atoms. The calculation of their group contributions, carried out by means of a fast Gauss–Seidel fitting calculus, used the experimental data of 5988 molecules from literature. An immediate subsequent ten-fold cross-validation test confirmed the extraordinary accuracy of the prediction of the molar refractivity, indicated by a correlation coefficient R2 and a cross-validated analog Q2 of 0.9997, a standard deviation σ of 0.38, a cross-validated analog S of 0.41, and a mean absolute deviation of 0.76%. The high reliability of the predictions was exemplified with three classes of molecules: ionic liquids and silicon- and boron-containing compounds. The corresponding molecular polarizabilities were calculated indirectly from the refractivity using the inverse Lorentz–Lorenz relation. In addition, it could be shown that there is a close relationship between the “true” volume and the refractivity of a molecule, revealing an excellent correlation coefficient R2 of 0.9645 and a mean absolute deviation of 7.53%.

Calculation of the Three Partition Coefficients logPow, logKoa and logKaw of Organic Molecules at Standard Conditions at Once by Means of a Generally Applicable Group-Additivity Method

“…The present study, which is part of an ongoing project, put to use a tool for the simple and reliable calculation of the two partition coefficients logP ow and logK oa that has proven its unmatched versatility in the equally reliable prediction of now up to 19 physical, thermodynamic, solubility-, optics-, charge-and environment-related molecular descriptors [13,[49][50][51][52][53][54][55], based on a common group-additivity method. The large database of more than 3300 and 1900 experimental data, respectively, upon which the group parameters for the logP ow and logK oa calculations are founded enabled their prediction for nearly 29,500 and more than 27,000 molecules, respectively, of the presently more than 37,100 compounds in ChemBrain's database.…”

Calculation of the Three Partition Coefficients logPow, logKoa and logKaw of Organic Molecules at Standard Conditions at Once by Means of a Generally Applicable Group-Additivity Method

“…The present study, which is part of an ongoing project, put to use a tool for the simple and reliable calculation of the two partition coefficients logPow and logKoa, that has proven its unmatched versatility in the equally reliable prediction of up to now 19 physical, thermodynamic, solubility-, optics-, charge-, and environment-related molecular descriptors [11,[44][45][46][47][48][49][50], based on a common group-additivity method. The large database of more than 3300 and 1900 experimental data, respectively, upon which the group parameters for the logPow and logKoa calculations are founded enabled their prediction for nearly 29500 and more than 27000 molecules, respectively, of the presently more than 37100 compounds in ChemBrain's database.…”