Díaz-Gallifa Pau, Fabelo Oscar, Pasán Jorge, Cañadillas-Delgado Laura, Lloret Francesc, Julve Miguel, Ruiz-Pérez Catalina
Laboratorio de Rayos X y Materiales Moleculares (MATMOL), Departamento de Física, Facultad de Ciencias, Universidad de La Laguna Avenida Astrofísico Francisco Sánchez s/n , E-38204 La Laguna, Tenerife, Spain.
Inorg Chem. 2014 Jun 16;53(12):6299-308. doi: 10.1021/ic5008582. Epub 2014 Jun 5.
Six new heterometallic cobalt(II)-lanthanide(III) complexes of formulas [Ln(bta)(H2O)2]2[Co(H2O)6]·10H2O [Ln = Nd(III) (1) and Eu(III) (2)] and [Ln2Co(bta)2(H2O)8]n·6nH2O [Ln = Eu(III) (3), Sm(III) (4), Gd(III) (5), and Tb(III) (6)] (H4bta = 1,2,4,5-benzenetretracaboxylic acid) have been synthesized and characterized via single-crystal X-ray diffraction. 1 and 2 are isostructural compounds with a structure composed of anionic layers of [Ln(bta)(H2O)2]n(n-) sandwiching mononuclear Co(H2O)6 cations plus crystallization water molecules, which are interlinked by electrostatic forces and hydrogen bonds, leading to a supramolecular three-dimensional network. 3-6 are also isostructural compounds, and their structure consists of neutral layers of formula [Ln2Co(bta)2(H2O)8]n and crystallization water molecules, which are connected through hydrogen bonds to afford a supramolecular three-dimensional network. Heterometallic chains formed by the regular alternation of two nine-coordinate lanthanide(III) polyhedra [Ln(III)O9] and one compressed cobalt(II) octahedron [Co(II)O6] along the crystallographic c-axis are cross-linked by bta ligands within each layer of 3-6. Magnetic susceptibility measurements on polycrystalline samples for 3-6 have been carried out in the temperature range of 2.0-300 K. The magnetic behavior of these types of Ln(III)-Co(II) complexes, which have been modeled by using matrix dagonalization techniques, reveals the lack of magnetic coupling for 3 and 4, and the occurrence of weak antiferromagnetic interactions within the Gd(III)-Gd(III) (5) and Tb(III)-Tb(III) (6) dinuclear units through the exchange pathway provided by the double oxo(carboxylate) and double syn-syn carboxylate bridges.
已合成了六种新的异金属钴（II）-镧系元素（III）配合物，其化学式为[Ln(bta)(H₂O)₂]₂[Co(H₂O)₆]·10H₂O [Ln = Nd(III) (1) 和 Eu(III) (2)] 以及 [Ln₂Co(bta)₂(H₂O)₈]ₙ·6nH₂O [Ln = Eu(III) (3), Sm(III) (4), Gd(III) (5), 和 Tb(III) (6)] （H₄bta = 均苯四甲酸），并通过单晶X射线衍射对其进行了表征。1和2是同构化合物，其结构由[Ln(bta)(H₂O)₂]ₙⁿ⁻阴离子层夹着单核[Co(H₂O)₆]²⁺阳离子以及结晶水分子组成，它们通过静电力和氢键相互连接，形成超分子三维网络。3 - 6也是同构化合物，其结构由化学式为[Ln₂Co(bta)₂(H₂O)₈]ₙ的中性层和结晶水分子组成，它们通过氢键相连，形成超分子三维网络。由两个九配位镧系元素（III）多面体[Ln(III)O₉]和一个压缩的钴（II）八面体[Co(II)O₆]沿晶体学c轴规则交替形成的异金属链在3 - 6的每层中通过bta配体交联。在2.0 - 300 K的温度范围内对3 - 6的多晶样品进行了磁化率测量。这些类型的Ln(III)-Co(II)配合物的磁行为，已通过矩阵对角化技术进行建模，结果表明3和4不存在磁耦合，而在Gd(III)-Gd(III)（5）和Tb(III)-Tb(III)（6）双核单元中通过双氧（羧酸盐）和双顺-顺羧酸盐桥提供的交换途径发生了弱反铁磁相互作用。
