1. Dinuclear and trinuclear cyano-bridged {DyIIIMIV} (M = W, Mo) single-ion magnets supported by pentadentate Schiff-base ligands.
- Author
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Mao, Pan-Dong, Sun, Hui-Ying, Yan, Fei-Fei, Zhang, Shi-Hui, Li, Xin-Feng, Zhou, Ren-He, Zhang, Yi-Quan, Meng, Yin-Shan, and Liu, Tao
- Subjects
SUPERCONDUCTING magnets ,COORDINATION polymers ,AB-initio calculations ,ACTIVATION energy ,LIGANDS (Chemistry) ,MAGNETIC relaxation ,MAGNETS - Abstract
The modular construction method provides a feasible way to construct pre-designed cyano-bridged {Ln
III MIV/V } systems with more attractive structures and adjustable interactions between 4d/5d and 4f ions. In this work, the pentadentate Schiff-base ligands H2 Ln (H2 L1 : 2,6-diacetylpyridine bis(nicotinoylhydrazone); H2 L2 : 2,6-diacetylpyridine bis(isonicotinoylhydrazone)) with multiple coordination sites were designed to coordinate with DyIII ions firstly, and then combined with K4 M(CN)8 ·2H2 O (M = W, Mo) by a liquid–liquid diffusion method to successfully synthesize two trinuclear structures {Dy[MIV (CN)8 ]0.5 (HL1 )(H2 O)3 }2 ·8H2 O (1: M = W; 2: M = Mo), and two dinuclear structures {[Dy[MIV (CN)8 ](H3 L2 )(H2 O)3 ]}·sol (3: M = W, sol = 11.5H2 O; 4: M = Mo, sol = 2CH3 OH·9.5H2 O). Interestingly, deprotonation occurs in ligand H2 L1 during the formation of complexes 1 and 2, while deprotonation/protonation processes both occur in ligand H2 L2 during the synthesis of complexes 3 and 4. Magnetic analyses reveal that complexes 1–4 are all field-induced single-ion magnets (SIMs). The energy barriers (Ueff /kB ) of complexes 1 and 2 are 92.83 K and 101.08 K, respectively, which are nearly three-fold higher than those of complexes 3 (30.19 K) and 4 (32.77 K). Ab initio calculations were performed on these series of {LnIII MIV } heteronuclear complexes to provide more insights into the magnetic relaxation properties. This work provides another example of improving the SMM behaviors of cyano-bridged {LnIII MIV } systems by deprotonation/protonation at different sites in the ligands. [ABSTRACT FROM AUTHOR]- Published
- 2023
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