具有跷跷板几何构型的四核镧系（III）配合物：合成、结构与磁性

Tetranuclear lanthanide(III) complexes in a seesaw geometry: synthesis, structure, and magnetism.

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

Inorg Chem. 2014 Apr 7;53(7):3385-91. doi: 10.1021/ic4027915. Epub 2014 Mar 10.

DOI:10.1021/ic4027915

PMID:24611541

Abstract

The reaction of 2-methoxy-6-(pyridin-2-ylhydrazonomethyl)phenol (LH) with Ln(III) (Ln = Gd, Tb, Dy, Ho) salts in the presence of an excess of triethylamine afforded [Gd4(L)4(μ4-OH)(μ3-OH)2(NO3)4]·(NO3)·4CH3CN·CH3OH·2H2O (1), [Tb4(L)4(μ4-OH)(μ3-OH)2(NO3)4]·(NO3)·4CH3CN·3H2O (2), [Dy4(L)4(μ4-OH)(μ3-OH)2(NO3)4]·(NO3)·6CH3CN·H2O (3), and [Ho4(L)4(μ4-OH)(μ-OH)2(NO3)4]·(NO3)·8CH3CN·3CH3OH·2H2O (4). All four complexes contain a monocationic tetranuclear core with a unique seesaw topology. The tetranuclear assembly is formed through the coordination of four L, one μ4-OH, two μ3-OH, and four chelating nitrate ligands, with a charge-balancing nitrate counteranion. Magnetic studies reveal a weak antiferromagnetic coupling throughout the series. Compound 1 can be modeled well with an isotropic exchange between all centers parametrized by J = -0.09 cm(-1). Compound 3 exhibits slow magnetic relaxation at low temperatures.

摘要

在过量三乙胺存在的情况下，2-甲氧基-6-(吡啶-2-基肼基亚甲基)苯酚(LH)与Ln(III)(Ln = Gd、Tb、Dy、Ho)盐反应，得到[Gd4(L)4(μ4-OH)(μ3-OH)2(NO3)4]·(NO3)·4CH3CN·CH3OH·2H2O(1)、[Tb4(L)4(μ4-OH)(μ3-OH)2(NO3)4]·(NO3)·4CH3CN·3H2O(2)、[Dy4(L)4(μ4-OH)(μ3-OH)2(NO3)4]·(NO3)·6CH3CN·H2O(3)和[Ho4(L)4(μ4-OH)(μ-OH)2(NO3)4]·(NO3)·8CH3CN·3CH3OH·2H2O(4)。所有四种配合物都含有一个具有独特跷跷板拓扑结构的单核四核核心。四核组装体是通过四个L、一个μ4-OH、两个μ3-OH和四个螯合硝酸根配体的配位形成的，带有一个电荷平衡的硝酸根抗衡阴离子。磁性研究表明，整个系列中存在弱反铁磁耦合。化合物1可以用所有中心之间的各向同性交换很好地模拟，参数J = -0.09 cm(-1)。化合物3在低温下表现出缓慢的磁弛豫。