Computational investigation of the SN2 reactivity of halogenated pollutants
Abstract/Contents
- Abstract
- The SN2 displacement reaction, in which a halide is displaced from a molecule by a nucleophile represents an important mechanism by which halogenated pollutants can be removed from the environment. Experimental SN2 transformation rates for halogenated pollutants vary widely and depend on both compound structure and whether the reaction takes place via abiotic or biological processes. I used computational methods to examine SN2 reactivity for a comprehensive set of halogenated compounds in order to develop structure-activity relationships, and to improve our understanding of the fundamental factors that govern reactivity of halogenated pollutants in the natural environment. I used a quantum chemistry method (Gaussian 98) to calculate activation energies and establish an order of reactivity for a comprehensive set of over 70 halogenated compounds. Examination of transition state structures and comparison to experimental and calculated measures of substrate electron affinity yielded valuable information about the nature of substituent effects. I employed a molecular docking algorithm (AUTODOCK) to study the effect of halogenated pollutant structure on enzyme-substrate interactions within the confined active sites of two haloalkane dehalogenase enzymes, and to understand the implications on catalysis by these enzymes. Output from both computational methods was then used in combination with experimentally derived properties to perform a statistical quantitative structure activity relationship (QSAR) analysis to develop models of reactivity. I identified the dominant structural effects on SN2 reactivity of halogenated pollutants, provided mechanistic insights about the origin of these effects, and demonstrated the importance of accounting for solvent and enzyme interactions in explaining observed transformation rates. My research provides a more complete picture of SN2 reactivity of halogenated pollutants based on sets of energies derived independently of experimental data. I have demonstrated that robust models can be developed from theoretical results that can account for the observed variability in experimental data as well as provide a means for estimation of SN2 transformation rates for untested compounds.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Copyright date | 2011 |
| Publication date | 2010, c2011; 2010 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Kawakami, Brett Taketsugu |
|---|---|
| Associated with | Stanford University, Civil & Environmental Engineering Department |
| Primary advisor | Reinhard, Martin |
| Thesis advisor | Reinhard, Martin |
| Thesis advisor | Hildemann, Lynn M. (Lynn Mary) |
| Thesis advisor | Leckie, Jim, 1939- |
| Advisor | Hildemann, Lynn M. (Lynn Mary) |
| Advisor | Leckie, Jim, 1939- |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Brett Taketsugu Kawakami. |
|---|---|
| Note | Submitted to the Department of Civil and Environmental Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2011. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2011 by Brett Taketsugu Kawakami
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