1. Octahedral–Tetrahedral Systems [Co(dppmO,O)3]2+[CoX4]2– Showing Slow Magnetic Relaxation with Two Relaxation Modes
- Author
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Ján Moncol, Roman Boča, Cyril Rajnák, Ján Titiš, and Filip Varga
- Subjects
Magnetic measurements ,010405 organic chemistry ,Chemistry ,Relaxation (NMR) ,Cationic polymerization ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,Crystallography ,Magnetic anisotropy ,Octahedron ,Ab initio quantum chemistry methods ,Tetrahedron ,Magnetic relaxation ,Physical and Theoretical Chemistry - Abstract
Three compounds with octahedral-tetrahedral Co(II) moieties of [Co( dppm O, O)3][CoX4] type, where X = SCN (1), Cl (2), or I (4) have been synthesized and characterized by the X-ray structure analysis (1 and 4), and spectroscopic methods. The dc magnetic measurements show high magnetic anisotropy for octahedral centers whereas tetrahedral sites possess moderate D values. These results are confirmed by the ab initio calculations. The ac susceptibility data reveals a slow magnetic relaxation for 2 and 4, similar to that of the X = Br analogue (3), whereas 1 displays no ac-absorption signal. There are two relaxation channels; the slower for 2 (4) possesses a relaxation time as long as τLF= 178 (588) ms at T = 1.9 K and Bdc = 0.7 T. Also, the half-Zn analogue, [Co( dppm O, O)3][ZnI4], shows slow magnetic relaxation with two relaxation channels conditioned by the cationic unit [Co( dppm O, O)3]2+.
- Published
- 2018
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