1. Enhancement of Single-Molecule Magnet Properties by Manipulating Intramolecular Dipolar Interactions.
- Author
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Huang JQ, Chen QW, Ding YS, Zhu XF, Wang BW, Pan F, and Zheng Z
- Abstract
A new single-molecule magnet (SMM) complex [K(18-crown-6)][(COT)Er(µ-Cl)
3 Er(COT)] (Er2 Cl3 , COT = cyclooctatetraenide dianion) is obtained by the reaction of [(COT)Er(µ-Cl)(THF)]2 (Er2 Cl2 , THF = tetrahydrofuran) with an equivalent of KCl in the presence of 18-crown-6. The two COT-Er units in the newly formed complex are triply bridged by µ-Cl ligands, leading to the "head-to-tail" alignment of the magnetic easy axes distinctly different from the "staggered" arrangement in the precursor complex. This structural transformation has led to significantly enhanced intramolecular dipolar interactions and a reduced transverse component of the crystal fields, increasing the energy barrier from 150(8) K for Er2 Cl2 to 264(4) K for Er2 Cl3 and extending its magnetic relaxation time at 2 K by 2500 times with respect to Er2 Cl2 . More importantly, the blocking temperature increased from lower than 2 K for Er2 Cl2 to 8 K for Er2 Cl3 , and the magnetic hysteresis loops at 2 K changed from butterfly-shaped for Er2 Cl2 to open hysteresis loop with coercive force of 7 kOe for Er2 Cl3 . These results suggest that the properties of SMMs can be effectively tuned and improved by rationally arranging magnetic spins via molecular engineering., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)- Published
- 2024
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