Quantum topological method studies on the thermodynamic properties of polychlorinated phenoxazines

•Novel quantum topological indices PY1,2 derived from molecular structure.•Quantum topological method on quantitative structure–property relationships of Phx and 135 PCPXs.•Model is statistically significant and shows good stability for data variation tested by leave-one-out cross-validation.

The novel quantum topological indices PY1,2 were derived from molecular structure combined with the effect of atom space, the character of bonding atoms (such as equilibrium electro-negativity) and the branching effect between the atoms. The quantitative structure–property relationships (QSPRs) were proposed between PY1,2 and the thermodynamic properties (△fHθ, △fGθ   and ΔfGRθ) of phenoxazine (Phx) and 135 kinds of polychlorinated phenoxazines (PCPXs), by Multiple linear regression (MLR) analysis method. The high-quality prediction models were evidenced by the correlation coefficient R, the standard error of estimate S, the Fisher statistic value and the cross-validated correlation coefficient RCV. With the new QSPR model, we are able to predict a wide range of thermodynamic properties of an extensive number of molecules. And the model is statistically significant and shows good stability for data variation as tested by the leave-one-out cross-validation (LOO-CV).