Predicting Melting Points by the Graovac-Pisanski Index

TL;DR

This paper demonstrates that the Graovac-Pisanski index, a molecular descriptor accounting for structure and symmetry, effectively predicts melting points across various hydrocarbon molecules in QSPR analysis.

Contribution

It introduces the use of the Graovac-Pisanski index for melting point prediction and shows its effectiveness for alkanes and other hydrocarbons.

Findings

Strong correlation between the index and alkane melting points

Effective prediction of melting points for hydrocarbons

Different regression models for various molecule families

Abstract

Theoretical molecular descriptors alias topological indices are a convenient means for expressing in a numerical form the chemical structure encoded in a molecular graph. The structure descriptors derived from molecular graphs are widely used in Quantitative Structure-Property Relationship (QSPR) and Quantitative Structure-Activity Relationship (QSAR). In this paper, we are interested in the Graovac-Pisanski index (also called modified Wiener index) introduced in 1991 by Graovac and Pisanski, which encounters beside the distances in a molecular graph also its symmetries. In the QSPR analysis we first calculate the Graovac-Pisanski index for different families of hydrocarbon molecules using a simple program and then we show a correlation with the melting points of considered molecules. We show that the melting points of the alkane series can be very effectively predicted by the Graovac-Pisanski index and for the rest of considered molecules (PAH's and octane isomers) the regression models are different, but we establish some correlation with the melting points for them as well.