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Single‐Molecule Magnetism in Three Dy 2 Complexes from the Use of a Pentadentate Schiff Base Ligand and Different Benzoates
Author(s) -
Ge Yu,
Li Dawei,
Wang Guoqing,
Cui Yanfeng,
Najib Muhammad Saleem,
Li Yahong,
Wang BaoLin
Publication year - 2019
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201900636
Subject(s) - dysprosium , antiferromagnetism , chemistry , crystallography , magnetism , ligand (biochemistry) , benzoates , magnetic susceptibility , benzoic acid , ion , schiff base , inorganic chemistry , condensed matter physics , physics , biochemistry , receptor , organic chemistry
Three dinuclear dysprosium(III) complexes, [Dy 2 L 2 (O 2 CPh) 2 ]⋅2 MeOH ( 1 ), [Dy 2 L 2 {(2‐NO 2 )O 2 CPh} 2 ] ( 2 ), and [Dy 2 L 2 {(2‐OH)O 2 CPh} 2 ] ⋅ MeOH ⋅ MeCN ( 3 ) (H 2 L= N 1 , N 3 ‐bis(4‐chlorosalicyladehyde)diethylenetriamine), have been synthesized and structurally characterized. Complexes 1 – 3 possess similar Ln 2 cores and differ in substituents at the benzyl rings of benzoates. Direct current (dc) magnetic susceptibility studies in the 2–300 K range showed weak antiferromagnetic interactions between two dysprosium(III) ions in 1 – 3 . The alternating current (ac) magnetic susceptibility measurements indicated that they all exhibited SMM behavior. The strategic attachment of the −NO 2 group (in 2 ) and the −OH functionality (in 3 ) on the skeleton of the benzoic acid led to subtle variations of the bond lengths and bond angles in the coordination environments of the central dysprosium(III) ions, consequently resulting in the enhancement of the energy barriers for 2 and 3 . Complete‐active‐space self‐consistent field (CASSCF) calculations were employed to rationalize the experimental outcomes. Theoretical calculations confirm the existence of antiferromagnetic interactions in 1 – 3 , and the calculated dc magnetic susceptibility data agree well with those obtained experimentally. The computational results reveal more axial g tensors, as well as higher first excited Kramers doublets in 2 and 3 ; thus resulting in higher energy barriers in compounds 2 and 3 .