Sie befinden Sich nicht im Netzwerk der Universität Paderborn. Der Zugriff auf elektronische Ressourcen ist gegebenenfalls nur via VPN oder Shibboleth (DFN-AAI) möglich. mehr Informationen...
Fine-Tuning of Uniaxial Anisotropy and Slow Relaxation of Magnetization in the Hexacoordinate Co(II) Complexes with Acidoligands
Ist Teil von
Journal of physical chemistry. C, 2020-11, Vol.124 (47), p.25957-25966
Ort / Verlag
American Chemical Society
Erscheinungsjahr
2020
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
A new hexacoordinate Co(II) complex with the general formula [CoL(NCS)2]·DMSO (1) (L = biscondensation product of diacetyl and 2-hydrazinyl-4,6-dimethylpyrimidine, DMSO = dimethylsulfoxide) exhibiting field-induced single-ion magnet (SIM) behavior has been obtained and characterized. To explain such field-induced SIM behavior, we have performed the analysis of the observed direct current (DC) magnetic properties based on the Griffiths Hamiltonian in combination with the high-level quantum-chemical calculations of the crystal field parameters. The complex has been shown to exhibit strong easy-axis-type magnetic anisotropy arising from a large negative value Δax = −1538.0 cm–1 of the axial crystal parameter, which is accompanied by a weak rhombic contribution with |Δrh| = 219.3 cm–1. Magnetic properties of 1 have been compared with the previously studied field-induced SIM compound [CoLCl2]·H2O (2). Introduction of a thiocyanide anion in 1 (instead of chloride in 2) in the Co(II) coordination sphere resulted in improvement of uniaxial magnetic anisotropy and switch of the relaxation process from the combination of direct and Raman mechanisms in 2 to Orbach-type one in complex 1. Effects of substitution of acidoligands in the Co(II) coordination sphere on the crystalline structure, DC magnetic properties, magnetic anisotropy, and magnetization relaxation processes have been rationalized.