Wydział Chemii

Katarzyna Choroba

Joanna Palion-Gazda

Barbara Machura

Alina Bieńko

Daria Wojtala

Dariusz Bieńko

Cyril Rajnák

Roman Boča

Andrew Ozarowski

Mykhaylo Ozerov

2024

Inorganic Chemistry

63

1068-1082

10.1021/acs.inorgchem.3c03405

Naukowa

Angielski

Artykuł

To get a better insight into understanding the factors affecting the enhancement of the magnetic anisotropy in single molecule (single ion) magnets, two cobalt(II) complexes based on a tridentate ligand 2,6-di(thiazol-2-yl)pyridine substituted at the 4-position with N-methyl-pyrrol-2-yl have been synthesized and studied by X-ray crystallography, AC and DC magnetic data, FIRMS and HFEPR spectra, and theoretical calculations. The change of the counteranion in starting Co(II) salts results in the formation of pentacoordinated mononuclear [Co(mpyr-dtpy)Cl₂]·2MeCN (1) complex and binuclear [Co(mpyr-dtpy)₂][Co(NCS)₄] (2) compound. The observed marked distortion of trigonal bipyramid geometry in 1 and cationic octahedral and anionic tetrahedral units in 2 brings up a question about the validity of the spin-Hamiltonian formalism and the possibility of determining the value and sign of the zero-field splitting D parameter. Both complexes exhibit field-induced slow magnetic relaxation with two or three relaxation channels at B_DC = 0.3 T. The high-frequency relaxation time in the reciprocal form τ(HF)⁻¹ = CTⁿ develops according to the Raman relaxation mechanism (for 2, n = 8.8) and the phonon-bottleneck-like mechanism (for 1, n = 2.3). The high-frequency relaxation time at T = 2.0 K and B_DC = 0.30 T is τ(HF) = 96 and 47 μs for 1 and 2, respectively.

Energy, Ligands, Magnetic properties, Mathematical methods, Quantum mechanics

http://dx.doi.org/10.1021/acs.inorgchem.3c03405

https://www.acs.org/content/acs/en.html