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Low‐Dimensional Carboxylate‐Bridged Gd III Complexes for Magnetic Refrigeration
Author(s) -
Liu SuiJun,
Xie ChenChao,
Jia JiMin,
Zhao JiongPeng,
Han SongDe,
Cui Yu,
Li Yue,
Bu XianHe
Publication year - 2014
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.201301586
Subject(s) - magnetic refrigeration , carboxylate , antiferromagnetism , ferromagnetism , crystallography , chemistry , ion , hydrothermal reaction , gadolinium , hydrothermal synthesis , hydrothermal circulation , materials science , stereochemistry , magnetization , magnetic field , condensed matter physics , physics , organic chemistry , quantum mechanics , seismology , geology
Abstract Four carboxylate‐bridged Gd III complexes ( 1 – 4 ) with 1D/2D structures have been synthesized by using the hydrothermal reaction of Gd 2 O 3 with various carboxylate ligands. Compounds 1 and 2 contained the same [2n] Gd III OH ladders, but with different crystallographically independent Gd III ions, whilst the structures of compounds 3 and 4 were composed of [Gd 4 (μ 3 ‐OH) 2 (piv) 8 (H 2 O) 2 ] 2+ units and 1D ladder Gd III chains, respectively. Antiferromagnetic interactions occurred in compounds 1 – 3 , owing to their small GdOGd angles, whereas ferromagnetic coupling occurred in compound 4 , in which the GdOGd angles were larger. These complexes exhibited a distinct magnetocaloric effect (MCE), which was affected by their different magnetic densities and exchange interactions. Among these compounds, complex 4 presented the largest MCE (−Δ S m max =43.6 J kg −1 K −1 ), the lowest M w / N Gd ratio (the highest magnetic density), and weak ferromagnetic coupling. Therefore, a lower M w / N Gd ratio and weaker exchange interactions (a smaller absolute value of θ ) between Gd III ions resulted in a larger MCE for the Gd III complexes.