(Pyrrole-2,5-Diyl)-Bis(Nitronyl Nitroxide) and-Bis(Iminonitroxide): Specific Features of the Synthesis, Structure, and Magnetic Properties
<b> </b>In contrast to diradicals connected by alternant hydrocarbons, only a few studies have addressed diradicals connected by nonalternant hydrocarbons and their heteroatom derivatives. Here, the synthesis, structure, and magnetic properties of pyrrole-2,5-diyl−linked bis(ni...
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MDPI AG
2020-03-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/25/7/1503 |
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| author | Evgeny Tretyakov Anastasia Tkacheva Galina Romanenko Artem Bogomyakov Dmitri Stass Alexander Maryasov Ekaterina Zueva Boris Trofimov Victor Ovcharenko |
| author_facet | Evgeny Tretyakov Anastasia Tkacheva Galina Romanenko Artem Bogomyakov Dmitri Stass Alexander Maryasov Ekaterina Zueva Boris Trofimov Victor Ovcharenko |
| author_sort | Evgeny Tretyakov |
| collection | DOAJ |
| description | <b> </b>In contrast to diradicals connected by alternant hydrocarbons, only a few studies have addressed diradicals connected by nonalternant hydrocarbons and their heteroatom derivatives. Here, the synthesis, structure, and magnetic properties of pyrrole-2,5-diyl−linked bis(nitronyl nitroxide) and bis(iminonitroxide) diradicals are described. The diradicals show characteristic electron spin resonance spectra in dilute glassy solutions, from which conclusions about the presence of distinct conformations, their symmetry, and interspin distance were made. X-ray diffraction analysis of the diradicals revealed that paramagnetic moieties lie in the plane of the pyrrole ring, because of the formation of an intramolecular hydrogen bond, O<sub>NO</sub>…HN, with O…H distances of 2.15−2.23 Å. The N−O groups participating in the formation of H-bonds have greater bond lengths (~1.29 Å) as compared with nonparticipating groups (~1.27 Å). The nitronyl nitroxide and iminonitroxide diradicals showed an intramolecular antiferromagnetic interaction, with <i>J</i> = −77.3 and −22.2 cm<sup>−1</sup>, respectively (H = −2<i>J</i><b>S</b><sub>1</sub><b>S</b><sub>2</sub>). |
| first_indexed | 2024-12-13T02:55:30Z |
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| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-12-13T02:55:30Z |
| publishDate | 2020-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-b624a756f994430db9ecc2736268c55c2022-12-22T00:01:57ZengMDPI AGMolecules1420-30492020-03-01257150310.3390/molecules25071503molecules25071503(Pyrrole-2,5-Diyl)-Bis(Nitronyl Nitroxide) and-Bis(Iminonitroxide): Specific Features of the Synthesis, Structure, and Magnetic PropertiesEvgeny Tretyakov0Anastasia Tkacheva1Galina Romanenko2Artem Bogomyakov3Dmitri Stass4Alexander Maryasov5Ekaterina Zueva6Boris Trofimov7Victor Ovcharenko8N. N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences, 9 Ac. Lavrentiev Avenue, 630090 Novosibirsk, RussiaInternational Tomography Center, Siberian Branch of Russian Academy of Sciences, 3a Institutskaya Str., 630090 Novosibirsk, RussiaInternational Tomography Center, Siberian Branch of Russian Academy of Sciences, 3a Institutskaya Str., 630090 Novosibirsk, RussiaInternational Tomography Center, Siberian Branch of Russian Academy of Sciences, 3a Institutskaya Str., 630090 Novosibirsk, RussiaV. V. Voevodsky Institute of Chemical Kinetics and Combustion, Siberian Branch of Russian Academy of Sciences, 3 Institutskaya Str., 630090 Novosibirsk, RussiaN. N. Vorozhtsov Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences, 9 Ac. Lavrentiev Avenue, 630090 Novosibirsk, RussiaKazan National Research Technological University, 68 Karl Marx Str., 420015 Kazan, RussiaA. E. Favorsky Institute of Chemistry, Siberian Branch of Russian Academy of Sciences, 1 Favorsky Str., Irkutsk 664033, RussiaInternational Tomography Center, Siberian Branch of Russian Academy of Sciences, 3a Institutskaya Str., 630090 Novosibirsk, Russia<b> </b>In contrast to diradicals connected by alternant hydrocarbons, only a few studies have addressed diradicals connected by nonalternant hydrocarbons and their heteroatom derivatives. Here, the synthesis, structure, and magnetic properties of pyrrole-2,5-diyl−linked bis(nitronyl nitroxide) and bis(iminonitroxide) diradicals are described. The diradicals show characteristic electron spin resonance spectra in dilute glassy solutions, from which conclusions about the presence of distinct conformations, their symmetry, and interspin distance were made. X-ray diffraction analysis of the diradicals revealed that paramagnetic moieties lie in the plane of the pyrrole ring, because of the formation of an intramolecular hydrogen bond, O<sub>NO</sub>…HN, with O…H distances of 2.15−2.23 Å. The N−O groups participating in the formation of H-bonds have greater bond lengths (~1.29 Å) as compared with nonparticipating groups (~1.27 Å). The nitronyl nitroxide and iminonitroxide diradicals showed an intramolecular antiferromagnetic interaction, with <i>J</i> = −77.3 and −22.2 cm<sup>−1</sup>, respectively (H = −2<i>J</i><b>S</b><sub>1</sub><b>S</b><sub>2</sub>).https://www.mdpi.com/1420-3049/25/7/1503nitronyl nitroxidesiminonitroxidesdiradicalspyrrole derivativesmagnetochemistryquantum-chemical calculations |
| spellingShingle | Evgeny Tretyakov Anastasia Tkacheva Galina Romanenko Artem Bogomyakov Dmitri Stass Alexander Maryasov Ekaterina Zueva Boris Trofimov Victor Ovcharenko (Pyrrole-2,5-Diyl)-Bis(Nitronyl Nitroxide) and-Bis(Iminonitroxide): Specific Features of the Synthesis, Structure, and Magnetic Properties Molecules nitronyl nitroxides iminonitroxides diradicals pyrrole derivatives magnetochemistry quantum-chemical calculations |
| title | (Pyrrole-2,5-Diyl)-Bis(Nitronyl Nitroxide) and-Bis(Iminonitroxide): Specific Features of the Synthesis, Structure, and Magnetic Properties |
| title_full | (Pyrrole-2,5-Diyl)-Bis(Nitronyl Nitroxide) and-Bis(Iminonitroxide): Specific Features of the Synthesis, Structure, and Magnetic Properties |
| title_fullStr | (Pyrrole-2,5-Diyl)-Bis(Nitronyl Nitroxide) and-Bis(Iminonitroxide): Specific Features of the Synthesis, Structure, and Magnetic Properties |
| title_full_unstemmed | (Pyrrole-2,5-Diyl)-Bis(Nitronyl Nitroxide) and-Bis(Iminonitroxide): Specific Features of the Synthesis, Structure, and Magnetic Properties |
| title_short | (Pyrrole-2,5-Diyl)-Bis(Nitronyl Nitroxide) and-Bis(Iminonitroxide): Specific Features of the Synthesis, Structure, and Magnetic Properties |
| title_sort | pyrrole 2 5 diyl bis nitronyl nitroxide and bis iminonitroxide specific features of the synthesis structure and magnetic properties |
| topic | nitronyl nitroxides iminonitroxides diradicals pyrrole derivatives magnetochemistry quantum-chemical calculations |
| url | https://www.mdpi.com/1420-3049/25/7/1503 |
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