A formulated as △fH m ? (PPDs,g)=a+ΣbiPi + cifi is put forward for estimating standard formation enthalpies of pyridine-derivatives (PDDs), in which,P i is path index andc i f i is an amended term of interac...A formulated as △fH m ? (PPDs,g)=a+ΣbiPi + cifi is put forward for estimating standard formation enthalpies of pyridine-derivatives (PDDs), in which,P i is path index andc i f i is an amended term of interaction between substituent and N atom on pyridine ring. The Calculations based on the model were carried out for some pyridine-derivatives. The values of standard formation enthalpy calculated are consistent with those in literature.展开更多
Two C16H12O4 isomers of derivatives of pagodane were firstly reported and studied by using DFT method. Geometries, energies, and vibrational frequencies have been calculated for the two C16H12O4 isomers with pagodane-...Two C16H12O4 isomers of derivatives of pagodane were firstly reported and studied by using DFT method. Geometries, energies, and vibrational frequencies have been calculated for the two C16H12O4 isomers with pagodane-like structures at the B3LYP/6-31G^＊＊ level of theory. Symmetries of isomer 1 and 2 are D2h and D2d, respectively. Heats of formation for the two C16H12O4 isomers have been estimated in this paper. According to the heats of formation, the two C16H12O4 isomers are more stable than pagodane. Heats of formation as well as the vibrational analysis indicate that the two C16H12O4 isomers enjoy sufficient stability to allow for the experimental preparation.展开更多
基金Supported by the National Natural Science Foundation of China!(29971024)
文摘A formulated as △fH m ? (PPDs,g)=a+ΣbiPi + cifi is put forward for estimating standard formation enthalpies of pyridine-derivatives (PDDs), in which,P i is path index andc i f i is an amended term of interaction between substituent and N atom on pyridine ring. The Calculations based on the model were carried out for some pyridine-derivatives. The values of standard formation enthalpy calculated are consistent with those in literature.
基金This work was supported by the Natural Science Foundation of Shandong Province (Y2002G11)
文摘Two C16H12O4 isomers of derivatives of pagodane were firstly reported and studied by using DFT method. Geometries, energies, and vibrational frequencies have been calculated for the two C16H12O4 isomers with pagodane-like structures at the B3LYP/6-31G^＊＊ level of theory. Symmetries of isomer 1 and 2 are D2h and D2d, respectively. Heats of formation for the two C16H12O4 isomers have been estimated in this paper. According to the heats of formation, the two C16H12O4 isomers are more stable than pagodane. Heats of formation as well as the vibrational analysis indicate that the two C16H12O4 isomers enjoy sufficient stability to allow for the experimental preparation.
