Theoretical Studies on the Molecular Structures and Thermodynamic Properties of Polychlorinated Fluorenes

T Geometric structures of 135 polychlorinated fluorene (PCFR) molecules were optimized using density functional theory (DFT) at the B3LYP/6-311G** level and their thermodynamic properties in the ideal gas state were calculated. The relations of these thermodynamic properties with the number and position of chlorine atoms were also explored, from which the relative stability of PCFR congeners was theoretically proposed according to the magnitude of the relative standard Gibbs free energy of formation (△_r,_fG~θ). The results show that the geometric configuration of PCFR isomers is determined by the position of chlorine atoms. There molecules. The change of △_fH~θ and △_fG~θ of most stable PCFR isomers with increasing the number of chlorine atoms is different from that in most unstable PCFR congeners. The values of △_fH~θ and △_fG~θ for PCFR isomers with the same number of chlorine atoms strongly depend on the position of chlorine atoms and the relative stability of PCFR congeners is mainly determined by intramolecular