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Oxidation and Reduction Process for Polycyclic Aromatic Hydrocarbons and Nitrated Polycyclic Aromatic Hydrocarbons

Tian, Zhenjiao
http://rave.ohiolink.edu/etdc/view?acc_num=osu1228333650

Abstract Details

2008, Doctor of Philosophy, Ohio State University, Chemistry.
Epoxidation is the first metabolic activation step necessary for polycyclic aromatic hydrocarbons (PAHs) to exert their biological activity. Nitrated polycyclic aromatic hydrocarbons (NPAHs) may undergo nitro reduction or ring oxidation, or a combination of ring oxidation and nitro reduction. We used density functional theory at the B3LYP/6-31+G**//B3LYP/6-31G* level of theory to explore both the reduction of NPAHs and epoxidation of PAHs and NPAHs. Substituent effects on the stability of nitrobenzene and its derivatives generated in the process of the nitro reduction were investigated. Two linear (free) energy relationships were observed: (1) a correlation between the enthalpy difference ΔH0meta [ΔH0 = H0 (meta) - H0 (para)] and the charge differences on the carbon bonded to the reaction site for neutral molecules; and (2) a correlation between the ΔH0meta and the Hammett substituent constant difference Δσ (Δσ = σm - σρ). We also explored substituent and solvent effects on the reduction, and linear Hammett correlations were obtained. The effects of ring systems on the reduction thermodynamics were also examined. Larger ring systems and azaheterocycles were found to be generally more feasibly reduced than the parent nitrobenzene system. The thermochemistry of the epoxidation reactions of various PAHs and NPAHs were explored. The regioselectivities of the epoxidations were found to be consistent with the available experimental data. We also investigated the isomerization process for arene oxides, derived from both PAHs and NPAHs, to form the corresponding oxepines. The calculated results quantitatively demonstrate the facility and the feasibility of the isomerization at room temperature. The results reveal the significant effect of the aromaticity changes on the isomerization. By comparing the results for NPAHs with the results for PAHs, the effect of the nitro group on the isomerization was found to be dependent on the location of the oxirane and the structure of the NPAH. The calculations also reveal that solvation effects on the isomerization of the NPAH oxides are different from and more complex than that of the parent PAH oxides. Our results elucidate the origin of the racemization of the optically active arene oxides.
Christopher M. Hadad, PhD (Advisor)
David J. Hart, PhD (Committee Member)
Jovica D. Badjic, PhD (Committee Member)
143 p.
Chemistry; Pharmacology
oxidation; epoxidation; reduction; Hammett Correlation; density function; computational chemistry; polycyclic aromatic hydrocarbons; nitrated metabolic activation; thermodynamic kinetic enthalpy; free energy; isomerization; oxepine

Recommended Citations

Citations

  • Tian, Z. (2008). Oxidation and Reduction Process for Polycyclic Aromatic Hydrocarbons and Nitrated Polycyclic Aromatic Hydrocarbons [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1228333650

    APA Style (7th edition)

  • Tian, Zhenjiao. Oxidation and Reduction Process for Polycyclic Aromatic Hydrocarbons and Nitrated Polycyclic Aromatic Hydrocarbons. 2008. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1228333650.

    MLA Style (8th edition)

  • Tian, Zhenjiao. "Oxidation and Reduction Process for Polycyclic Aromatic Hydrocarbons and Nitrated Polycyclic Aromatic Hydrocarbons." Doctoral dissertation, Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1228333650

    Chicago Manual of Style (17th edition)

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© 2008, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.