A QSPR Investigation of Octane Isomers Using Degcity Indices

K. B. Sudhakara; P. S. Guruprasad; M. A. Sriraj

doi:10.59828/pijms.v2i5.52

Authors

K. B. Sudhakara Department of Mathematics, Government Science College, Hassan-573 201, India Author https://orcid.org/0000-0003-4039-5011
P. S. Guruprasad Department of Mathematics, Government First Grade College, K.G.F.-563122, India Author https://orcid.org/0000-0002-8539-519X
M. A. Sriraj Department of Mathematics, Vidyavardhaka College of Engineering, Mysuru-570 002, India Author https://orcid.org/0000-0003-3805-4082

DOI:

https://doi.org/10.59828/pijms.v2i5.52

Keywords:

Degcity indices, MLR, Octane isomers, QSPR analysis, Topological index

Abstract

This study examines the use of degcity indices as molecular descriptors for modelling selected physicochemical properties of octane isomers. Seven indices involving vertex degree and eccentricity are considered. Simple linear regression is first used to investigate the individual correlations between these descriptors and entropy (S), acentric factor (AF), enthalpy of vaporization (ΔH_vap), standard enthalpy of vaporization (ΔH⁰_vap), and heat capacity (CP). Multiple linear regression models are then developed using backward stepwise selection. Their goodness of fit is assessed through the correlation coefficient, coefficient of determination, adjusted coefficient of determination and F-statistic. Predictive performance is further examined by leave-one-out cross-validation (LOOCV). The resulting models give comparatively strong results for S, AF, ΔH_vap and ΔH⁰_vap, whereas the model for CP has limited predictive performance. The findings illustrate the potential, as well as the limitations, of degcity indices for QSPR modelling of the considered octane isomers.