Tb/3d-Tb clusters derived from a 1,4,7-triazacyclononane-based hexadentate ligand with field-induced slow magnetic relaxation and oxygen-sensitive luminescence

• Published in: New journal of chemistry 2019-03, Vol.43 (1), p.467-474
• Main Authors: Wen, He-Rui, Zhang, Jia-Li, Liang, Fu-Yong, Yang, Kai, Liu, Sui-Jun, Liao, Jin-Sheng, Liu, Cai-Ming
• Format: Article
• Language: English
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/c8nj05777j

A family of new Tb III and 3d-Tb III cluster complexes, namely [Tb(L)(CH 3 COCH 3 )] ( 1 ), [Tb 2 (μ-H 2 O)(L) 2 ] ( 2 ), [Zn 2 Tb(L) 2 ]·ClO 4 ( 3 ) and [Ni 2 Tb(L) 2 ]·ClO 4 ( 4 ) (H 3 L = N , N ′, N ′′-tris(3,5-dimethyl-2-hydroxybenzyl)-1,4,7-triazacyclononane), have been synthesized through the reaction of H 3 L and metal salts. Structural analysis reveals that 1 and 2 exhibit mononuclear and binuclear structures, respectively, and both 3 and 4 exhibit trinuclear 3d-4f-3d structures. Interestingly, complex 1 could undergo reversible transformation to complex 2 by adjusting the reaction solvents. The alternating current (ac) magnetic susceptibilities of 3 reveal that out-of-phase ( χ ′′) is frequency- and temperature-dependent, which is a typical feature of field-induced slow magnetic relaxation with an energy barrier of 35.71 K. Moreover, complexes 1-3 show strong oxygen-sensitive luminescence, with typical narrow emission bands of lanthanide ions. The luminescence intensity and lifetime ( 5 D 4 of Tb III ) of 3 are obviously stronger than those of 1 and 2 . Therefore, complex 3 can be considered as a good candidate as a bi-functional magneto-luminescent molecular material. A family of new Tb III /3d-Tb III cluster complexes based on N , N ′, N ′′-tris(3,5-dimethyl-2-hydroxybenzyl)-1,4,7-triazacyclononane have been synthesized and they exhibit interesting magnetic and luminescent properties.