Open AccessAsymmetric Assembly of Chiral Lanthanide(III) Tetranuclear Cluster Complexes Using Achiral Mixed Ligands: Single-molecule Magnet Behavior and Magnetic Entropy Change
Author(s) -
CaiMing Liu,
Xiang Hao
Publication year - 2022
Publication title -
acs omega
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.779
H-Index - 40
ISSN - 2470-1343
DOI - 10.1021/acsomega.2c02155
Subject(s) - magnetic refrigeration , crystallography , single molecule magnet , lanthanide , magnet , molecule , materials science , cluster (spacecraft) , dumbbell , magnetic field , magnetic relaxation , stereochemistry , chemistry , magnetization , physics , medicine , ion , organic chemistry , quantum mechanics , computer science , programming language , physical therapy
It is challenging to use achiral ligands to spontaneously construct chiral molecular magnets. In this work, two new Ln 4 cluster complexes based on N , N '-(1,3-propanediyl)bis[ N -[1,1-bis(hydroxymethyl)-2-hydroxyethyl]amine] (H 6 L) have been assembled, which are crystallized in a chiral space group due to the asymmetric distribution of acetate (OAc - ) groups and hexafluoroacetylacetonate (F 6 acac - ) groups on both sides of the parallelogram-like Ln 4 core. Complex 1 , [Dy 4 (H 3 L) 2 (OAc) 3 (F 6 acac) 3 ]·5MeOH·2H 2 O, exhibits single-molecule magnet properties at the zero field with the U eff / k value of 48.4 K; notably, besides the Orbach process, the Raman process is also prominent for the magnetic relaxation of 1 . Complex 2 , [Gd 4 (H 3 L) 2 (OAc) 3 (F 6 acac) 3 ]·4MeOH·2.5H 2 O, displays a large magnetocaloric effect, whose largest -Δ S m value is 21.88 J kg -1 K -1 (when T = 2 K and Δ H = 5 T); it thus can be utilized as a good magnetic refrigeration molecular material.