Evidence for zero-field slow magnetic relaxation in a Co(ii) complex with a pseudo-tetrahedral N2I2 environment

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Evidence for zero-field slow magnetic relaxation in a Co(ii) complex with a pseudo-tetrahedral N2I2 environment

Dalton Transactions. 2022. Vol. 51. No. 311. P. 11916–11921.

Аничкин А. А., Yureva E. A., Korchagin, D. V., Shilov G. V., Babeshkin K. A., Efimov N. N., Palii A. V., Aldoshin S. M.

Herein, we report on the synthesis, structure and magnetic properties of a four-coordinate mononuclear Co(ii) diiodide complex with the 3,5-dimethylpyrazole ligand. A distorted tetrahedral local coordination environment around the central cobalt ion is formed by the two nitrogen atoms of two monodentate pyrazole ligands and by iodide ions. Direct current (dc) magnetic measurements in combination with ab initio SA-CASSCF/NEVPT2 quantum-chemical calculations revealed a strong easy-axis-type magnetic anisotropy with a record value Dexp = −30.58(3) cm−1 of the axial zero field splitting parameter for pseudo-tetrahedral Co(ii)-based CoL2Hal2 complexes. Moreover, it is the only complex in this series demonstrating the slow relaxation of magnetization at zero dc field. The Orbach process is shown to be the dominant mechanism of magnetic relaxations in the high temperature range, while the quantum tunneling of magnetization produces the leading contribution to the overall relaxation at temperatures below 4 K.

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On the Issue of Biological Activity of Cobalt bis(dicarbollide) Derivatives: Conformation of the [8-EtO-8’-I-3,3’-Co(1,2-C2B9H10)2]− Anion

Dudarova N., Kosenko I., Varvara E. Maltseva et al., Journal of Cluster Science 2025 Vol. 36 No. 5 Article 161

The conformational mobility of the [8-EtO-8’-I-3,3’-Co(1,2-C2B9H10)2]− anion, which has been chosen as a model compound for many potential drugs based on cobalt bis(dicarbollide), was studied by 1H NMR spectroscopy, single crystal X-ray diffraction and quantum chemical calculations. According to the results of quantum chemical calculations, the most favourable conformation for [8-EtO-8’-I-3,3’-Co(1,2-C2B9H10)2]− is the transoid conformation, which is stabilized by one ...

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Odintsova E., Journal of Molecular Liquids 2018 Vol. 264 P. 343–351

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Evidence for zero-field slow magnetic relaxation in a Co(II) complex with a pseudo-tetrahedral N2I2 environment

Yureva E. A., Korchagin D. V., Anichkin A. A. et al., Dalton Transactions 2022 Vol. 51 P. 11916–11921

Herein, we report on the synthesis, structure and magnetic properties of a four-coordinate mononuclear Co(II) diiodide complex with the 3,5-dimethylpyrazole ligand. A distorted tetrahedral local coordination environment around the central cobalt ion is formed by the two nitrogen atoms of two monodentate pyrazole ligands and by iodide ions. Direct current (dc) magnetic measurements in combination ...

Added: November 15, 2022

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Buikin P., Vologzhanina A. V., Arkhipov D. E. et al., Russian Chemical Bulletin 2022 Vol. 71 No. 6 P. 1111–1122

Anionic complexes LSi(CatR)2 (L is a chelate N-methyl-N-(acetamido)methyl-C,O group or (2-oxo-1-hexahydroazepinyl)methyl-C,O group; CatR is a substituted catecholate ligand) were studied by quantum chemistry at the PBE0/6-311G(d,p) and RI-MP2/def2-TZVPP levels with inclusion of nonspecific solvation using the PCM model. It was shown that the nature of substituents in the catecholate phenyl ring and the L group ...

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Kramarova E. P., Negrebetskii V. V., Volodin A. D. et al., Russian Journal of Coordination Chemistry/Koordinatsionnaya Khimiya 2022 Vol. 48 No. 10 P. 647–658

Abstract: A series of anionic phenylsilicon(IV) bis-catecholate complexes, where (Cat1)– = catecholate, (Cat2)– = 3,4,5,6-tetrabromocatecholate, (Cat3)– = 4-cyanocatecholate, (Cat4)– = 4-nitrocatecholate, (Cat5)– = 3-fluorocatecholate, and (Cat6)– = 4,5-dibromocatecholate, were prepared by the reaction of trimethoxyphenylsilane with two equivalents of catechol or its derivatives containing electron-withdrawing substituents in the benzene ring in the presence of dicyclohexylamine. The complexes were characterized by IR ...

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Tkachev V., Bozhenko K., Utenyshev A. et al., Известия РАН. Серия химическая 2021 Т. 70 № 5 С. 847–856

The structure of the newly synthesized palladium(ii) 3,5-di(tert-butyl)-2-oxyazobenzene, PdL2, was determined by X-ray diffraction. The metal chelate was found to adopt an unusual domed conformation, with the trans-planar coordination unit at the top. This is the first complex of this class, the domed structure of which was confirmed by X-ray diffraction and in which the ...

Added: September 14, 2021

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Ionov A. M., Ageeva T., Golubev D. et al., Macroheterocycles 2018 Vol. 11 No. 2 P. 155–161

Synthesis of bismuth complexes of etioporphyrin II, protoporphyrin IX dimethyl ester and three tetraphenylporphyrin derivatives in which iodine atom is an extraligand, was carried out. Obtained compounds were characterized by mass spectrometry, UV-vis, 1H NMR spectroscopy, and HPLC. The study of X-ray spectra showed that bismuth valence is +3. Bismuth atom coordinates four nitrogen atoms ...

Added: December 10, 2020