|
ИСТИНА |
Войти в систему Регистрация |
ИСТИНА ИНХС РАН |
||
5-Fluoro-1-Methyl-Pyrazol-4-yl-Substituted Nitronyl Nitroxide Radical and Its 3d Metal Complexes: Synthesis, Structure, and Magnetic Propertiesстатья
Дата последнего поиска статьи во внешних источниках: 29 января 2024 г.
- Авторы: Kudryavtseva Ekaterina, Andrey Serykh, Bogdan Ugrak, Dutova Tatyana, Nasyrova Darina, Aleshin Dmitrii, Efimov Nikolay, Dorovatovskii Pavel, Bogomyakov Artem, Fokin Sergey, Romanenko Galina, Sergeeva Anna, Tretyakov Evgeny
- Журнал: Crystals
- Том: 13
- Год издания: 2023
- Издательство: MDPI
- Местоположение издательства: Basel, Switzerland
- Первая страница: 1655
- DOI: 10.3390/catal13081206
- Аннотация: The metal–radical approach is a well-established synthetic way toward multi-spin systemsthat relies on the coordination of stable radical ligands with transition metal ions. The advantageoffered by the use of paramagnetic ligands is that metal–radical magnetic exchange coupling isdirect between the magnetic orbitals of the radical and metal ion. With the aim of further exploring this approach, crystals of four heterspin complexes, [M(hfac)2LF]2 {M = Mn, Co, or Ni and hfac = hexafluoroacetylacetonate} and [Cu(hfac)2LF]n, were obtained using a new fluorinated pyrazolyl-substituted nitronyl nitroxide radical, 4,4,5,5-tetramethyl-2-(5-fluoro-1-methyl-1H-pyrazol-4-yl)-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (LF) as a ligand. The newly synthesized complexeswere fully characterized, including X-ray crystallography and magnetometry. XRD analysis revealed that complexes [M(hfac)2LF]2 have similar dimer structures in which a metal ion is in asix-coordinated environment with four O atoms from the two hfac ligands, one radical O atom, andone pyrazole N atom from ligand LF. Nonetheless, the packing patterns of the complexes were foundto be considerably different. In [Mn(hfac)2LF]2, there are no magnetically important short contactsbetween manganese dimers. By contrast, in [Co(hfac)2LF]2 and [Ni(hfac)2LF]2, there are short contacts between non-coordinate O atoms of nitronyl nitroxide moieties. Magnetic behaviors of [M(hfac)2LF]2 showed that the M ions and the directly coordinated radicals are strongly antiferromagnetically coupled (JMn-ON = 84.1 1.5 cm1, JCo-ON = 134.3 2.6 cm1, and JNi-ON = 276.2 2.1 cm1; ˆH = 2J ˆ * S M ˆ * S NO). Notably, the magnetization of [Mn(hfac)2LF]2 having molecular structure proved to be accompanied by hysteresis. The [Cu(hfac)2LF]n complex has a chain-polymer structure with alternating magnetic fragments: three spin exchange clusters {ONO–Cu(II)–ONO} and {Cu(II)} ions. Despite the direct coordination of radicals, its magnetic properties are weakly ferromagnetic (JCu-ON = 14.8 0.3 cm1).
- Добавил в систему: Серых Андрей Антонович