QSPR Study Of Organic Pollutants Based On Topological Index And 3D-QSAR

Persistent organic pollutants(POPs),whose distribution ranges more widely,have been a growing threat to humans,plants and animals.It creates a large number of demand that determining physicochemical properties and bioical activity for POPs.However,experimental determination is a hard work because of the complexity of analytical methods,high cost of experiments,large expenditures of time and lack of the standards.Moreover,some POPs which is difficult to obtain pure material are inconvenient experimentally determined.Thus,the method of experimental determination of the indicators of POPs is difficult to implement.Quantitative structure-property/activity relationship(QSPR/QSAR)method,which is able to obtain the predicted values of these properties from the molecular structure,provides a way to solve this problem.Therefore,this paper carried out QSPR / QSAR studies of POPs.In the first chapter,QSPR/QSAR method,its origins and study procedures are introduced.The research progress of QSPR/QSAR in forecasting the properties of POPs are reviewed.In the second chapter,the QSPR for super-cooled liquid vapour pressures(PL)of polybrominated diphenyl ethers(PBDEs)was investigated.The molecular distance–edge vector(MDEV)index was used as the structural descriptor.The quantitative relationship between the MDEV index and PL was modelled by multivariate linear regression(MLR)and an artificial neural network(ANN).The leave-one-out cross validation and k-fold cross validation were performed to assess the prediction ability of the developed models.It was demonstrated that the established models were practicable for predicting the PL values of PBDEs.Subsequently,an MLR model,and an ANN model,were developed.The two models could be used to predict the PL value of each PBDE.In the third,fourth and fifth chapters,the QSPR for the photolysis half-life(t1/2)of polychlorinateddibenzo-p-dioxins and polychlorinated dibenzofurans(PCDD/Fs)on spruce(Picea abies(L.)Karst.)needle surfaces under sunlight irradiation was investigated.The quantitative relationship between the t1/2 and structure of PCDD/Fs was modeled by using the methods based on topoical index,holographic QSAR(HQSAR)and 3D-QSAR respectively.Leave-one-out cross validation and external validation were carried out toassess the prediction ability of the developed models.All the developed modell can be used to predict the t1/2 of PCDD/Fs.Thus,the t1/2 of each PCDD/F congener was predicted by using the developedmodels.Furthermore,HQSAR model gave the contribution of molecular fragments to molecular properties,the potential map obtained by the 3D-QSAR models can be used to guide on how to accelerate decomposition of PCDD/Fs practically.