Single molecule magnet behavior and magnetic refrigeration of four tetranuclear lanthanide (Ln = Gd, Tb, Dy) clusters

• Published in: New journal of chemistry 2019-12, Vol.43 (48), p.19429-19436
• Main Authors: Yu, Hong, Cao, Jia-Miao, Zhang, Jun-Rui, Li, Rui-Cong, Cheng, Yan, Yang, Chen, Hou, Yin-Ling, Fang, Ming
• Format: Article
• Language: English
• Subjects: Clusters; Crystallography; Ligands; Magnetic properties; Oxygen atoms; Refrigeration
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/c9nj04260a

Four tetranuclear lanthanide clusters: {[Gd 4 (L 1 ) 6 (tmhd) 4 (μ 3 -OH) 2 ]·2CH 3 CN} ( 1 ), {[Tb 4 (L 1 ) 6 (tmhd) 4 (μ 3 -OH) 2 ]·4CH 3 CN} ( 2 ), {[Dy 4 (L 1 ) 6 (tmhd) 4 (μ 3 -OH) 2 ]·CH 3 CN} ( 3 ) and {[Gd 4 (L 2 ) 6 (tmhd) 4 (μ 3 -OH) 2 ]·8CH 3 CN·2CH 2 Cl 2 } ( 4 ) were fabricated by employing two Schiff based ligands (HL 1 = 5-((4-ethylbenzylidene)amino)quinolin-8-ol and HL 2 = 5-(([1,1′-biphenyl]-4-ylmethylene)amino)quinolin-8-ol). Interestingly, the cores of compounds 1-4 are nearly structurally identical. The core of the compounds contains a tetranuclear arrangement of Ln III ions, which is held together by two pyramidal μ 3 -OH − ions and six μ 2 phenol hydroxyl oxygen atoms derived from six ligands. Magnetic studies indicated that 1 and 4 exhibit a cryogenic magnetic refrigeration property (maximum −Δ S m = 18.02 J K −1 kg −1 for 1 , and 15.47 J K −1 kg −1 for 4 , Δ H = 7 T at 2.0 K), whereas compound 3 exhibits a slow relaxation of magnetization with an energy barrier ( U eff / k B ) of 83.1 K and τ 0 = 4.18 × 10 −8 s. Four lanthanide complexes were fabricated and characterized. 1 and 4 exhibit a cryogenic magnetic refrigeration property and 3 displays slow relaxation of magnetization.