DFT Study of Structural and Thermodynamic Properties for Polybrominated 5,10-Dihydrophenazines

Abstract

The structural and thermodynamic properties of 75 polybrominated 5,10-dihydrophenazines (PBDPs) in the ideal gas state at 298.15 K and 1.013 × 10 5 Pa have been calculated at the B3LYP/6-31G* level using the Gaussian 03 program. The isodesmic reactions are developed to calculate the standard enthalpy of formation ( f H θ ) and standard free energy of formation ( f G θ ) of PBDP congeners. The relationships of these thermodynamic parameters with the number and position of the Br atom substitution (N PBS ) are discussed, and it is found that there exists a high correlation between thermodynamic parameters and N PBS . In addition, the correlations between structural parameters and N PBS are discussed. High correlations were found between the energy of the highest occupied molecular orbital (E HOMO ), the most negative atomic partial charge in the molecule (q − ) and N PBS , and all R 2 values are larger than 0.90.

Studies of thermodynamic properties and relative stability of a series of polyfluorinated dibenzo-p-dioxins by density functional theory

“…The most stable isomer The most unstable isomer 19.111 kJ mol −1 than that for 2,7-DFDD, with two fluorines attached on two different aromatic rings.…”

“…Studies have shown that lots of compounds, such as PCDDs/PCDFs, polychlorinated thianthrenes, and polychlorinated phenoxathiins, have been explored by B3LYP density functional theory [13][14][15][16]. Also, thermodynamic data of polybrominated dibenzofurans, polybrominated phenoxazine, polybrominated 5,10-dihydrophenazines and polybrominated phenoxathiins were calculated by the same method [17][18][19][20], and the relative stability of their isomers was theoretically proposed. The results showed that the thermodynamic properties of these compounds were found to be closely related with the number and position of Cl or Br substitution.…”

Photodegradation of Polyfluorinated Dibenzo-p-Dioxins in Organic Solvents: Experimental and Theoretical Studies

“…However, with a great deal of expenditures of time and equipment it becomes difficult to obtain the data on the photochemical process of all POPs by an experimental method. In comparison with fund and time-consuming experimental assessments, theoretical calculations were found to be an effective and inexpensive method for predicting the environmental behavior and fate of POPs. ,− Thus, we investigated the photolysis of PFDDs in organic solvents using both experimental and theoretical methods.…”