Enantioselective self-assembly of triangular Dy3 clusters with single-molecule magnet behavior

Shuang-Yan Lin; Chao Wang; Lang Zhao; Jinkui Tang

doi:10.1002/asia.201402670

Enantioselective self-assembly of triangular Dy3 clusters with single-molecule magnet behavior

Chem Asian J. 2014 Dec;9(12):3558-64. doi: 10.1002/asia.201402670. Epub 2014 Sep 18.

Authors

Shuang-Yan Lin¹, Chao Wang, Lang Zhao, Jinkui Tang

Affiliation

¹ State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (P. R. China), Fax: (+86) 431-85262878; University of Chinese Academy of Sciences, Beijing, 100039 (P. R. China).

PMID: 25234668
DOI: 10.1002/asia.201402670

Abstract

Three pairs of enantiopure chiral triangular Ln3 clusters, [Ln3LRRRRRR/SSSSSS(μ3-OH)2(H2O)2(SCN)4]⋅xCH3OH⋅yH2O (R-Dy3, Ln=Dy, x=6, y=0; S-Dy3, Ln=Dy, x=6, y=1; R-Ho3, Ln=Ho, x=6, y=1; S-Ho3, Ln=Ho, x=6, y=1; R-Er3, Ln=Er, x=6, y=0; S-Er3, Ln=Er, x=6, y=1), have been successfully synthesized by a rational enantioselective synthetic strategy. The core of triangular Ln3 is bound in the central N6O3 of the macrocyclic ligand, and the coordination spheres of Ln ions are completed by four SCN(-) anions and two H2O molecules in axial positions of the macrocycle. The circular dichroism (CD) and vibrational circular dichroism (VCD) spectra of the enantiomers demonstrate that the chirality is successfully transferred from the ligands to the resulting Ln3 clusters. Ac susceptibility measurements reveal that single-molecule magnet behavior occurs for both enantiopure clusters of R-Dy3 and S-Dy3. This work is one of the few examples of the successful design of a pair of triangular Dy3 clusters showing simultaneously slow magnetic relaxation and optical activity, and this might open up new opportunities to develop novel multifunctional materials.

Keywords: chirality; lanthanides; macrocycles; magnetic properties; single-molecule magnets.