Two novel topological electro-negativity indices based on distance matrix,named YC and WC indices,were proposed to be used for modeling properties of multiple bond organic compounds by equilibrium electro-negativity o...Two novel topological electro-negativity indices based on distance matrix,named YC and WC indices,were proposed to be used for modeling properties of multiple bond organic compounds by equilibrium electro-negativity of atom and relative bond length of molecule.A quantitative structural property relationship(QSPR) model for estimating flash point of 92 compounds was developed based on the newly introduced topological electro-negativity indices YC and WC and path number parameter P3.The model correlation coefficient and standard error for training set in multiple linear regression were 0.9923 and 5.28,respectively.The average absolute error of flash point was only 3.86 K between experimental and calculated values,and the relative error was 1.46%.Furthermore,the model was strictly tested by both internal and external validations.The predicted values were in good agreement with experimental values for leave-one-out(LOO),and the training set and validation set.The results show that this QSPR model is of good stability and powerful prediction ability.展开更多
In this paper,Topological Electronegativity Index (TEI) was developed to express the relatively power of an group in a molecule to attract electrons to itself.The charge effect,the relaxation effect and the electrosta...In this paper,Topological Electronegativity Index (TEI) was developed to express the relatively power of an group in a molecule to attract electrons to itself.The charge effect,the relaxation effect and the electrostatic field effect on the C 1s core ionization energies of saturated molecules were evaluated,based on the topological electronegativity index TEI,the atomic electronegativity χP and the polarizability α.The charge effect was scaled by the topological electronegativity index discrepancy between the C and X (X is atom or group) in the C-X bond.The relaxation effect (induced dipole) was scaled by the charge on the ionized carbon atom together with the polarizabiliy of the X.The electrostatic field effect was scaled by the charges on the atoms attached directly to the ionized carbon atom.Further,the shielding effect ΔSi of the C 1s electron in the saturated molecules was expressed by the charge effect and the relaxation effect together with the electrostatic field effect.By introducing the ΔSi into the Slater model,a Slater-like model was obtained for calculating the C 1s core ionization energy E1,C of saturated molecules,whose correlation coefficient r is 0.99943 and the average absolute error between the calculated and the experimental C 1s core ionization energies is only 0.094eV for 81 saturated molecules.Also the cross-correlation was tested by the leave-one-out (LOO) cross-validation method,and the obtained model has good predictive ability and stability (the correlation coefficient rcv is 0.99928,the average absolute error between the predicted and the experimental values is only 0.105 eV).展开更多
文摘Two novel topological electro-negativity indices based on distance matrix,named YC and WC indices,were proposed to be used for modeling properties of multiple bond organic compounds by equilibrium electro-negativity of atom and relative bond length of molecule.A quantitative structural property relationship(QSPR) model for estimating flash point of 92 compounds was developed based on the newly introduced topological electro-negativity indices YC and WC and path number parameter P3.The model correlation coefficient and standard error for training set in multiple linear regression were 0.9923 and 5.28,respectively.The average absolute error of flash point was only 3.86 K between experimental and calculated values,and the relative error was 1.46%.Furthermore,the model was strictly tested by both internal and external validations.The predicted values were in good agreement with experimental values for leave-one-out(LOO),and the training set and validation set.The results show that this QSPR model is of good stability and powerful prediction ability.
文摘In this paper,Topological Electronegativity Index (TEI) was developed to express the relatively power of an group in a molecule to attract electrons to itself.The charge effect,the relaxation effect and the electrostatic field effect on the C 1s core ionization energies of saturated molecules were evaluated,based on the topological electronegativity index TEI,the atomic electronegativity χP and the polarizability α.The charge effect was scaled by the topological electronegativity index discrepancy between the C and X (X is atom or group) in the C-X bond.The relaxation effect (induced dipole) was scaled by the charge on the ionized carbon atom together with the polarizabiliy of the X.The electrostatic field effect was scaled by the charges on the atoms attached directly to the ionized carbon atom.Further,the shielding effect ΔSi of the C 1s electron in the saturated molecules was expressed by the charge effect and the relaxation effect together with the electrostatic field effect.By introducing the ΔSi into the Slater model,a Slater-like model was obtained for calculating the C 1s core ionization energy E1,C of saturated molecules,whose correlation coefficient r is 0.99943 and the average absolute error between the calculated and the experimental C 1s core ionization energies is only 0.094eV for 81 saturated molecules.Also the cross-correlation was tested by the leave-one-out (LOO) cross-validation method,and the obtained model has good predictive ability and stability (the correlation coefficient rcv is 0.99928,the average absolute error between the predicted and the experimental values is only 0.105 eV).
