DFT studies of ESR parameters for N-O centered radicals, N-alkoxyaminyl and aminoxyl radicals
Copyright © 2011 John Wiley & Sons, Ltd.
| Veröffentlicht in: | Magnetic resonance in chemistry : MRC. - 1985. - 49(2011), 9 vom: 30. Sept., Seite 603-10 |
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| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2011
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| Zugriff auf das übergeordnete Werk: | Magnetic resonance in chemistry : MRC |
| Schlagworte: | Journal Article 14N hfcc DFT calculation ESR NO centered radical PCM g-factor hybrid functional |
| Zusammenfassung: | Copyright © 2011 John Wiley & Sons, Ltd. Theoretical calculations of ESR parameters for aminoxyl radicals have been widely studied using the density functional theory (DFT) calculations. However, the isomer N-alkoxyaminyl radicals have been limitedly studied. With the use of experimental data for 46 N-alkoxyaminyl and 38 aminoxyl radicals, the isotropic (14)N hyperfine coupling constants (aN ) and g-factors have been theoretically estimated by several DFT calculations. The best calculation scheme of aN for N-alkoxyaminyl radicals was PCM/B3LYP/6-31 + + G(d,p) (R(2) = 0.9519, MAE = 0.034 mT), and that for aminoxyl radicals was PCM/BHandHLYP/6-31 + + G(3df,3pd) (R(2) = 0.9336, MAE = 0.057 mT). For aminoxyl radicals, the solvation models in calculations enhanced the accuracy of reproducibility. In contrast, for N-alkoxyaminyl radicals the calculations with solvation models provided no improvement. The differences in the best functionals between two types of radicals were thought to come from the contribution ratios of neutral and dipolar canonical structures in resonance forms. The aN for N-alkoxyaminyl radicals that were stabilized by small contribution of dipolar canonical structures could be precisely reproduced by B3LYP with only 20% HF exact exchange. In contrast, the aN for aminoxyl radicals stabilized by large contribution of dipolar canonical structures was well reproduced by BHandHLYP with 50% HF exchange. The best calculation scheme of g-factors was IEFPCM/B3LYP/6-31 + G(d,p) (R(2) = 0.9767, MAE = 0.0001) for not only aminoxyl but also N-alkoxyaminyl radicals |
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| Beschreibung: | Date Completed 21.05.2015 Date Revised 03.11.2014 published: Print-Electronic Citation Status PubMed-not-MEDLINE |
| ISSN: | 1097-458X |
| DOI: | 10.1002/mrc.2792 |