Combination of Neural Networks and DFT Calculations for the Comprehensive Analysis of FDMPO Radical Adducts from Fast Isotropic Electron Spin Resonance Spectra

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• 作者：Katerina Makarova ; Ekaterina V. Rokhina ; Elena A. Golovina ; Henk Van As ; Jurate Virkutyte
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：January 12, 2012
• 年：2012
• 卷：116
• 期：1
• 页码：443-451
• 全文大小：962K
• 年卷期：v.116,no.1(January 12, 2012)
• ISSN：1520-5215

文摘

The 4-hydroxy-5,5-dimethyl-2-trifluoromethylpyrroline-1-oxide (FDMPO) spin trap is very attractive for spin trapping studies due to its high stability and high reaction rates with various free radicals. However, the identification of FDMPO radical adducts is a challenging task since they have very comparable Electron Spin Resonance (ESR) spectra. Here we propose a new method for the analysis and interpretation of the ESR spectra of FDMPO radical adducts. Thus, overlapping ESR spectra were analyzed using computer simulations. As a result, the N- and F-hyperfine splitting constants were obtained. Furthermore, an artificial neural network (ANN) was adopted to identify radical adducts formed during various processes (e.g., Fenton reaction, cleavage of peracetic acid over MnO₂, etc.). The ANN was effective on both 鈥渒nown鈥?FDMPO radical adducts measured in slightly different solvents and not a priori 鈥渒nown鈥?FDMPO radical adducts. Finally, the N- and F-hyperfine splitting constants of 路OH, 路CH₃, 路CH₂OH, and CH₃(C鈺怬)O^路 radical adducts of FDMPO were calculated using density functional theory (DFT) at the B3LYP/6-31G(d,p)//B3LYP/6-31G++//B3LYP/EPR-II level of theory to confirm the experimental data.