Structural Characterization And Molecular Modelling For Representative Chemicals

Compound structures determine their nature and each character is closely related to their structures. Therefore, it is great significant that analysis and study their change rules between molecular structure characterizations and physico-chemical properties or biological activities. Building quantitative relationships between molecular structures and properties, and explaining and predicting the properties and functions of the material from theory are very important to quantitative structure activity/property relationships (QSAR/ QSPR). The key is to find the simple molecular structural descriptors which can efficiently reflect the molecular itself. Therefore, author built series simple descriptors according to molecular structural characterization of 35 nitrobenzenes and 135 polychlorinated biphnylsisomers, respectively. The molecular descriptors can not only represent substituents' differences, but also reflect the positions of substituents. The equations are established between molecular structure parameters and nitrobenzene acute toxicity for black head stupid fish, polychlorinated biphnylsisomers of gas chromatography retention index by using multivariate linear regression method, respectively. The results indicate that the models built by our methods show both better stability and stronger external predictive capability that ones by leave-one-out (LOO) cross validation and Jackknife random sample test. At the same time the author proposes a novel atom valence shell electron quantum topologiacal index based on topologidal chemical principle and atom valence shell electron structure characters with the help of hidden core graph of ground state atom valence shell electrons. With combining even ionization energy of atom valance shell electrons, a set of new scale for elemental electronegativity is put forward. Using the formula of elemental electronegativity certain elemental electronegativity vacants in the Periodic Table are filled. The methods can be also applied in the expansion of the series of rare earth compounds, and the results indicate that the index established has excellent structural selectivity and...