非平面七核镧系（III）配合物的合成、结构与磁性

Synthesis, structure, and magnetism of non-planar heptanuclear lanthanide(III) complexes.

作者信息

Goura Joydeb, Walsh James P S, Tuna Floriana, Chandrasekhar Vadapalli

机构信息

Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India.

出版信息

Dalton Trans. 2015 Jan 21;44(3):1142-9. doi: 10.1039/c4dt01603c.

DOI:10.1039/c4dt01603c

PMID:25412282

Abstract

The reaction of the hydrazone, 2-methoxy-6-(pyridin-2-yl-hydrazonomethyl) phenol (LH) with lanthanide(iii) nitrate salts in the presence of excess triethylamine afforded the heptanuclear Ln(iii) complexes: [Gd7(L)6(μ3-OH)8(NO3)4(H2O)]·(NO3)3·8CH3CN·H2O (), [Tb7(L)6(μ3-OH)8(NO3)4]·(NO3)3·9CH3CN·2CH3OH·3H2O (), [Dy7(L)6(μ3-OH)8(NO3)4(H2O)]·(NO3)3·7CH3CN·3H2O (), [Ho7(L)6(μ3-OH)8(NO3)4]·(NO3)3·11CH3CN·2CH3OH·2H2O () and [Er7(L)6(μ3-OH)8(NO3)4]·(NO3)3·8CH3CN·2CH3OH (). Single crystal X-ray diffraction studies reveal that these complexes are tri-cationic, possessing three nitrate counter anions. The heptanuclear ensemble is non-planar and consists of six L and eight μ3-OH ligands. These compounds show an interesting structural motif with two incomplete cubes fused to each other through a common Ln(iii) ion. Compound exhibits a magnetocaloric effect, with (-ΔSm(T) = 27.7 J kg(-1) K(-1) at 3 K and under a field change of 0-7 T), while compound shows slow magnetic relaxation at very low temperatures.

摘要

腙2-甲氧基-6-(吡啶-2-基-腙甲基)苯酚(LH)与硝酸镧(iii)盐在过量三乙胺存在下反应，得到七核Ln(iii)配合物：[Gd7(L)6(μ3-OH)8(NO3)4(H2O)]·(NO3)3·8CH3CN·H2O ()、[Tb7(L)6(μ3-OH)8(NO3)4]·(NO3)3·9CH3CN·2CH3OH·3H2O ()、[Dy7(L)6(μ3-OH)8(NO3)4(H2O)]·(NO3)3·7CH3CN·3H2O ()、[Ho7(L)6(μ3-OH)8(NO3)4]·(NO3)3·11CH3CN·2CH3OH·2H2O ()和[Er7(L)6(μ3-OH)8(NO3)4]·(NO3)3·8CH3CN·2CH3OH ()。单晶X射线衍射研究表明，这些配合物是三阳离子的，含有三个硝酸根抗衡阴离子。七核聚集体是非平面的，由六个L和八个μ3-OH配体组成。这些化合物呈现出一种有趣的结构基序，即两个不完整的立方体通过一个共同的Ln(iii)离子相互融合。化合物表现出磁热效应，在3 K且磁场变化为0 - 7 T时，(-ΔSm(T)=27.7 J kg(-1) K(-1))，而化合物在非常低的温度下表现出缓慢的磁弛豫。