A quantative relationship exists between the structrue and physical properties of organic compounds.The molecular structrue of the examined compounds is selectively described by a molecular distance-edge（MDE）vector....A quantative relationship exists between the structrue and physical properties of organic compounds.The molecular structrue of the examined compounds is selectively described by a molecular distance-edge（MDE）vector.The physical properties of alkanes such as boiling points,density at 25℃,refractive index at 25℃, heat capacity at 300K,Gibbs energy,enthalpy at 300K are estimated with satisfactory results by a novel modified back- propagation neural network method based on the above MDEvectot.展开更多
Based on the identical group as a pseudo atom instead of a typical atom, a novel modified molecular dis-tance-edge (MDE) vector μ was developed in our laboratory to characterize chemical structure of polychlorinated ...Based on the identical group as a pseudo atom instead of a typical atom, a novel modified molecular dis-tance-edge (MDE) vector μ was developed in our laboratory to characterize chemical structure of polychlorinated diben-zofurans (PCDFs) congeners and/or isomers. Quantitative structure-retention relationships (QSRRs) between the new VMDE parameters and gas chromatographic (GC) retention behavior of PCDFs were then generated by multiple linear regression (MLR) method for non-polar, moderately polar, and polar stationary phases. Four excellent models with high correlation coefficients, R=0.984-0.995, were proposed for non-polar columns (DB-5, SE-54, OV-101). For the moder-ately polar columns (OV-1701), the correlation coefficient of the developed good model is only 0.958. For the polar col-umns (SP-2300), the QSRR model is poor with R=0.884. Then cross validation with leave-one out of procedure (CV) is performed in high correlation with the non-polar (Rcv=992-0.974) and weakly polar (Rcv=921) columns and in little cor-relation (Rcv=0.834) with the polar columns. These results show that the new μ vector is suitable for describing the re-tention behaviors of PCDFs on non-polar and moderately polar stationary phases and not for the various gas chroma-tographic retention behaviors of PCDFs on the different po-larity-varying stationary phases.展开更多
文摘A quantative relationship exists between the structrue and physical properties of organic compounds.The molecular structrue of the examined compounds is selectively described by a molecular distance-edge（MDE）vector.The physical properties of alkanes such as boiling points,density at 25℃,refractive index at 25℃, heat capacity at 300K,Gibbs energy,enthalpy at 300K are estimated with satisfactory results by a novel modified back- propagation neural network method based on the above MDEvectot.
基金This work was supported by the Chunhui Project Fund of the Ministry of Education(Grant No.SCPF99-4-4+37)Fok Ying-Tung Educational Foundation(Grant No.FYTF98-7-6)+1 种基金Chongqing Applied Science Fund(Grant No,CASF01-3-6)Chongqing University ZYXT Innovation Fund(Grant No.CUIF03-5-6+04-10-10).
文摘Based on the identical group as a pseudo atom instead of a typical atom, a novel modified molecular dis-tance-edge (MDE) vector μ was developed in our laboratory to characterize chemical structure of polychlorinated diben-zofurans (PCDFs) congeners and/or isomers. Quantitative structure-retention relationships (QSRRs) between the new VMDE parameters and gas chromatographic (GC) retention behavior of PCDFs were then generated by multiple linear regression (MLR) method for non-polar, moderately polar, and polar stationary phases. Four excellent models with high correlation coefficients, R=0.984-0.995, were proposed for non-polar columns (DB-5, SE-54, OV-101). For the moder-ately polar columns (OV-1701), the correlation coefficient of the developed good model is only 0.958. For the polar col-umns (SP-2300), the QSRR model is poor with R=0.884. Then cross validation with leave-one out of procedure (CV) is performed in high correlation with the non-polar (Rcv=992-0.974) and weakly polar (Rcv=921) columns and in little cor-relation (Rcv=0.834) with the polar columns. These results show that the new μ vector is suitable for describing the re-tention behaviors of PCDFs on non-polar and moderately polar stationary phases and not for the various gas chroma-tographic retention behaviors of PCDFs on the different po-larity-varying stationary phases.
