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Updated: Nov 26, 2025
Site Directed Spin Labeling and EPR Spectroscopic Studies of Pentameric Ligand-Gated Ion Channels
Published on: July 4, 2016
Evolution from a single relaxation process to two-step relaxation processes of Dy2 single-molecule magnets via the
Dawei Li1, Man-Man Ding, Yuan Huang
1College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China. liyahong@suda.edu.cn.
Abstract:
To explore the influences of magnetic interactions on the relaxation dynamics of single-molecule magnets (SMMs) and to understand the relationship between single-ion relaxation and the relaxation of a molecular entity, it is very important to design dinuclear lanthanide-based SMMs with two-step relaxation processes. Here, three Dy2 complexes of compositions [Dy2(L)2(NO3)2(MeOH)2] (1), [Dy2(L)2(NO3)2(EtOH)2] (2), and [Dy2(L)2(NO3)2(DMF)2]·0.5EtOH (3) (H2L = 2-(((2-hydroxy-3-methoxybenzyl)imino)methyl)-4-methoxyphenol) were successfully synthesized via elaborately introducing different terminal solvent ligands. X-ray single-crystal diffraction analyses revealed that complexes 1-3 are isostructural. The two DyIII ions of 1 and 2 both adopt D2d symmetry, while the two DyIII centres of 3 display D2d and D4d symmetries, respectively. The magnetic property studies of 1-3 indicated that all three complexes exhibit single-molecule magnet (SMM) behaviours with energy barriers of 104 K for 1, 98.94 K for 2, and 76.28 K and 45.54 K for 3 under zero dc field. The target of assembling Dy2 SMMs with two-step relaxation processes was achieved by gradually increasing the sizes of the terminal solvent ligands. Complex 3 exhibits two-step relaxation processes. Complete active space self-consistent field (CASSCF) calculations were performed on 1-3 to rationalize the observed differences in the magnetic behaviour. It is found that both the angles θ between the magnetic axis and the vector connecting two DyIII ions and the symmetries of DyIII ions are vital factors that affect the energy barriers of 1-3. The high local symmetries of the central metals in 1 and 2 make the complexes act as SMMs with higher energy barriers, while the smaller θ angle and different symmetries of the two DyIII ions render complex 3 as a SMM with a two-step relaxation process. This work demonstrates a new methodology for preparing SMMs with two-step relaxation processes by fine-tuning the terminal solvent ligands.
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