On use of the variable Zagreb vM2 index in QSPR: Boiling points of benzenoid hydrocarbons

Abstract

The variable Zagreb vM2 index is introduced and applied to the structure-boiling point modeling of benzenoid hydrocarbons. The linear model obtained (the standard error of estimate for the fit model S fit=6.8°C) is much better than the corresponding model based on the original Zagreb M2 index (Sfit=16.4°C). Surprisingly, the model based on the variable vertex-connectivity index (S fit=6.8°C) is comparable to the model based on vM 2 index. A comparative study with models based on the vertex-connectivity index, edge-connectivity index and several distance indices favours models based on the variable Zagreb vM2 index and variable vertex-connectivity index. However, the multivariate regression with two-, three- and four-descriptors gives improved models, the best being the model with four-descriptors (but vM2 index is not among them) with Sfit=5°C, though the four-descriptor model contaning vM2 index is only slightly inferior (Sfit=5. 3°C).