Assembly of Hydrazine-Bridged Cyclic FeIII4LnIII4 Octanuclear Complexes
Assembly of Hydrazine-Bridged Cyclic FeIII4LnIII4 Octanuclear Complexes
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肼桥环状 Fe(4)(III)Ln(4)(III) 八核配合物的组装
DOI：
10.1021/acs.cgd.1c01222
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发表时间：
2022-01-21
影响因子：
3.8
通讯作者：
Kou, Hui-Zhong
中科院分区：
文献类型：
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作者：
Jin, Yi-Shu;Wang, Xuan;Kou, Hui-Zhong
三个同晶环状八核簇合物[Fe（4）Ln（4）（L）（8）（H2O）（4）-（NO3）（4）]（NO3）（4）的精心设计与合成（Ln = Dy（1&BCH_3;5CH（3）CN &BCH_3;14H（2）O），Gd（2 &BH; 5CH（3）CN &BH; 19 H（2）O），Y（3 &BH; 6CH（3）CN &BH; 16 H（2）O）与席夫碱配体H2 L（2-（羟基亚氨基）丙酸（二吡啶-2基亚甲基）酰肼）反应得到了新的配合物。配体H2 L具有N-3-内配位和N2 O-外配位，分别螯合低自旋Fe（III）和Ln（III）。稀土离子周围剩余的配位位点被硝酸根离子和水分子占据。这是首次报道在配体中引入肼基连接Fe-Ⅲ和Ln（III）离子，不仅可以稳定分子环的骨架，而且可以传递Fe-Ⅲ和Ln（III）（Ln = Dy，Gd）离子之间弱的反铁磁相互作用。在1600 Oe的外加直流磁场下的交流磁化率测量揭示了配合物1的SMM行为，U-eff = 25.8 K。配合物2中Fe（III）和Gd（III）之间的磁交换量为2 J（FeGd）=-0.324cm（-1），同时配合物2在2K、5 T下表现出中等的磁热效应（MCE），-Δ S_m = 17.06J·kg（-1）·K ~（-1）.
The elaborate design and synthesis of three isomorphous cyclic octanuclear clusters [Fe(4)Ln(4)(L)(8)(H2O)(4)-(NO3)(4)](NO3)(4) (Ln = Dy (1 & BULL;5CH(3)CN & BULL;14H(2)O), Gd (2 & BULL; 5CH(3)CN & BULL;19H(2)O), Y (3 & BULL;6CH(3)CN & BULL;16H(2)O)) with the Schiff base ligand H2L (2-(hydroxyimino)propionic acid (dipyridin-2ylmethylene)hydrazide) have been achieved. The compartmental ligand H2L has N-3-inner and N2O-outer coordination sites, which chelate low-spin Fe(III) and Ln(III), respectively. The remaining coordination sites around the rare-earth ions are occupied by nitrate ions and water molecules. This is the first report on the use of a hydrazine group within a ligand to connect Fe-III and Ln(III) ions, which can not only stabilize the skeleton of the molecular ring but also transmit a weak antiferromagnetic interaction between Fe-III and Ln(III) (Ln = Dy, Gd) ions. ac magnetic susceptibility measurements under an external applied dc field of 1600 Oe reveal the SMM behavior of complex 1 with U-eff = 25.8 K. The magnitude of the magnetic exchange between Fe(III) and Gd(III) in complex 2 is evaluated to be 2J(FeGd) = -0.324 cm(-1); meanwhile, complex 2 shows a moderate magnetocaloric effect (MCE) with -& UDelta;S-m = 17.06 J kg(-1) K-1 under 5 T at 2 K.