Thiacalix[4]arene-supported mononuclear lanthanide compounds: slow magnetic relaxation in dysprosium and erbium analogues

• Published in: New journal of chemistry 2018-11, Vol.42 (22), p.17968-17974
• Main Authors: Ge, Jing-Yuan, Chen, Zhongyan, Wang, Hai-Ying, Wang, Haiou, Wang, Peng, Duan, Xing, Huo, Dexuan
• Format: Article
• Language: English
• Subjects: Absorption spectra; Crystal structure; Crystallography; Dysprosium compounds; Erbium compounds; Format; Ligands; Magnetic induction; Magnetic measurement; Magnetic properties; Magnetic relaxation; Magnets; Single crystals; Structural analysis; X ray spectra
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/c8nj04016h

Four mononuclear lanthanide compounds, [Ln(TC4A-di-OMe)(L OEt )] (Ln = Tb ( 1 ); Dy ( 2 ); Ho ( 3 ); Er ( 4 )), were synthesized based on a thiacalix[4]arene derivative (H 2 TC4A-di-OMe = 5,11,17,23-tetrakis(1,1-dimethylethyl)-25,27-dihydroxy-26,28-dimethoxy thiacalix[4]arene) and one auxiliary ligand (L OEt = (η 5 -cyclopentadienyl)tris-(diethylphosphito- p )cobaltate( iii )). Compounds 1-4 were characterized using single crystal X-ray structural analysis and magnetization measurements. The Ln( iii ) ion features a seven-coordinated {LnO 7 } environment, capped by one bowl-shaped thiacalix[4]arene ligand and one tripodal L OEt ligand. Magnetic measurements reveal that dysprosium compound 2 shows a characteristic two-step relaxation process while erbium compound 4 behaves as a field-induced single-molecule magnet with a higher energy barrier at 31.7 K. The mononuclear erbium-based compound based on the macrocyclic multidentate thiacalix[4]arene ligand is rarely observed in molecular magnets. Four mononuclear Ln III compounds have been synthesized, and the dysprosium and erbium analogues exhibit typical field-induced SMM behavior.