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Mononuclear Heptacoordinated 3d-Metal Helicates as a New Family of Single Ion Magnetsстатья
- Авторы: Tupolova Yulia P., Korchagin Denis V., Andreeva Anastasya S., Tkachev Valery V., Shilov Gennadii V., Lazarenko Vladimir A., Popov Leonid D., Babeshkin Konstantin A., Efimov Nikolay N., Morgunov Roman B., Palii Andrei V., Kubrin Stanislav P., Shcherbakov Igor N., Aldoshin Sergey M.
- Журнал: Magnetochemistry
- Том: 8
- Год издания: 2022
- Издательство: MDPI
- Местоположение издательства: Basel, Switzerland
- Номер статьи: 153
- DOI: 10.3390/magnetochemistry8110153
- Аннотация: The series of Co(II), Fe(II), and Ni(II) mononuclear coordination compounds of [CoL(NCS)2]·3DMSO(1), [CoL(H2O)2](ClO4)2·DMSO (2), [CoL(H2O)(EtOH)][CoCl4]·2H2O (2a), [FeL(NCS)2]·DMSO (3),and [NiL(NCS)2]·CH3CN (4) composition (where L is 2,6-bis(1-(2-(4,6-dimethylpyrimidin-2-yl)hydrazineylidene)ethyl)pyridine), with an [MLA2] coordination unit (where A is a pair of apical mon-odentate ligands), was synthesized. In compounds 1, 2, 2a, and 3, the ligand L is pentadentate, andcobalt and iron ions are placed in a heavily distorted pentagonal pyramidal coordination environment,while in 4 the Ni(II) ion is hexacoordinated. Easy plane-type magnetic anisotropy (D = 13.69, 11.46,19.5, and 6.2 cm−1 for 1, 2, 2a, and 4, respectively) was established for cobalt and nickel compounds,while easy axis-type magnetic anisotropy (D = −14.5 cm−1) was established for iron compound 3.The cobalt coordination compounds 1 and 2 show SIM behavior under a 1500 Oe external magneticfield, with effective magnetization reversal barriers of 65(1) and 60(1) K for 1 and 2, respectively.The combination of Orbach and Raman relaxation mechanisms was shown to adequately describethe temperature dependence of relaxation times for 1 and 2. CASSCF/NEVPT2 calculations wereperformed to model the parameters of the effective spin Hamiltonian for the compounds under study.
- Добавил в систему: Алдошин Сергей Михайлович