Magnetocaloric Properties of Heterometallic 3d–Gd Complexes Based on the [Gd(oda)3]3− Metalloligand |
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| Authors: | Jiang‐Zhen Qiu Long‐Fei Wang Yan‐Cong Chen Ze‐Min Zhang Quan‐Wen Li Prof?Dr Ming‐Liang Tong |
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| Affiliation: | Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry & Chemical Engineering, Sun Yat‐Sen University, Guangzhou, 510275 (P. R. China), Fax: (+86)?20‐8411‐2245 |
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| Abstract: | A series of heterometallic 3d–Gd3+ complexes based on a lanthanide metalloligand, M(H2O)6]Gd(oda)3] ? 3 H2O M=Cr3+ ( 1‐Cr )] (H2oda=2,2′‐oxydiacetic acid), M(H2O)6]MGd(oda)3]2 ? 3 H2O M=Mn2+ ( 2‐Mn ), Fe2+ ( 2‐Fe ) and Co2+ ( 2‐Co )], and M3Gd2(oda)6(H2O)6] ? 12 H2O M=Ni2+ ( 3‐Ni ), Cu2+ ( 3‐Cu ), and Zn2+ ( 3‐Zn )], are reported. Magnetic and heat‐capacity studies revealed a significant impact on the magnetocaloric effect depending on the anisotropy of the 3d transition metal ions, as confirmed by comparison of the observed maximum values of ?ΔSm between complexes 2‐Co and 1‐Cr . In these two complexes, the 3d metal ions have the same spin (S=3/2 for Co2+ and Cr3+ ions), and the theoretical calculation suggested a larger ?ΔSm value for 2‐Co (47.8 J K?1 kg?1) than 1‐Cr (37.5 J K?1 kg?1); however, the significant anisotropy of Co2+ ions in 2‐Co , which can result in smaller effective spins, gives a smaller value of ?ΔSm for 2‐Co (32.2 J K?1 kg?1) than for 1‐Cr (35.4 J K?1 kg?1) at ΔH=9 T. |
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| Keywords: | carboxylate ligands heterometallic complexes lanthanides magnetic properties transition metals |
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