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A Family of Double Cubanes {Cr III 2 Ln III 4 O 6 } (Ln = Tb, Ho, Er, Yb, Y) Based on Sulfate: Single‐Molecule Magnet Behavior in the Terbium and Erbium Analogues
Author(s) -
Xiang Hua,
Lu WenGuan,
Jiang Long,
Zhang WeiXiong,
Lan Yanhua
Publication year - 2016
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201501285
Subject(s) - crystallography , antiferromagnetism , chemistry , magnetic susceptibility , metal , ferromagnetism , diamagnetism , space group , cubane , lanthanide , crystal structure , x ray crystallography , diffraction , ion , physics , condensed matter physics , magnetic field , organic chemistry , quantum mechanics , optics
The synthesis and characterization of a family of compounds (pipzH 2 )[Cr III 2 Ln III 4 (µ 4 ‐O) 2 (µ 3 ‐OH) 4 (H 2 O) 10 (µ 3 ‐SO 4 ) 4 (SO 4 ) 2 ] · 2H 2 O [hereafter abbreviated as Cr 2 Ln 4 ; Ln = Tb ( 1 ), Ho ( 2 ), Er ( 3 ), Yb ( 4 ), and Y ( 5 ); pipz = piperazine] are reported. The compounds were obtained from hydrothermal reactions of Ln(NO 3 ) 3 · 6H 2 O (Ln = Tb, Ho, Er, Yb, and Y), Cr(NO 3 ) 3 · 9H 2 O, Na 2 SO 4 , and pipz in a 2:1:3:4 molar ratio. Single‐crystal X‐ray diffraction studies revealed that 1 – 5 crystallize isomorphously in the space group P 2 1 / c with Z = 2. The metallic core is composed of a rare face‐fused double‐cubane [Cr III 2 Ln III 4 (µ 4 ‐O 2– ) 2 (µ 3 ‐OH – ) 4 ] 10+ unit. The temperature dependence of bulk magnetic susceptibilities is indicative of antiferromagnetic interactions dominant in the Tb, Ho, and Er compounds. In fitting with the data of the diamagnetic Y III analogue, the interactions of Cr–Cr in this system are determined to be ferromagnetic with a coupling strength of 3.61(11) cm –1 , but the type of Cr–Ln could be antiferromagnetic. The dynamic magnetic properties revealed the presence of slow magnetic relaxation in the Tb and Er analogues, which represent two rare examples of Cr III ‐containing clusters that exhibit single‐molecule magnet (SMM) behavior.