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首页> 外文期刊>Polyhedron: The International Journal for Inorganic and Organometallic Chemistry >Cobalt(II) and copper(II) assembling through a functionalized oxamate-type ligand
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Cobalt(II) and copper(II) assembling through a functionalized oxamate-type ligand

机译：钴（II）和铜（II）通过功能性草酸酯型配体组装

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Two new metal complexes of formula {[Co(Hpcpa)(H_2O)_3]_n·3/2nH_2O} (1) and [Cu_2(MeHpcpa)_4(MeOH)_2] ·H_2O·3.68 MeOH (2) [H_3pcpa = N-(4-carboxyphenyl)oxamic acid and MeH_2pcpa = methyl ester derivative of H_3pcpa] have been synthesized and their structures determined by X-ray diffraction. 1 is a neutral zigzag chain of cobalt(II) ions bridged by Hpcpa~(2-) ligands exhibiting the bidentate/monodentate coordination mode. Each cobalt(II) ion is six-coordinate with three mer positioned water molecules, two oxamate- oxygens from a Hpcpa~(2-) ligand and a carboxylate-oxygen from another Hpcpa~(2-) group building a somewhat distorted octahedral surrounding. The intrachain cobalt-cobalt separation is 11.326(2) ?. The structure of 2 consists of discrete syn-syn tetracarboxylate-bridged dicopper(II) units of the paddle wheel-type, the oxamate fragment of the MeHpcpa ligand being not involved in the coordination. Each copper(II) ion is five-coordinate in a distorted square pyramidal environment with four carboxylateoxygens in the basal plane and a methanol molecule in the apical position. The intradimer copper-copper separation is 2.5974(11) ?. The magnetic properties of 1 and 2 have been investigated in the temperature range 1.9-300 K. The magnetic behavior of 1 corresponds to that of a magnetically isolated high-spin cobalt(II) ion with an important orbital contribution. The analysis of its magnetic data through the Hamiltonian, H = -αλL_(Co) · S_(Co) + ?[L_(ZCo~2) - 2/3] + βH(-aL_(Co) + g_eS_(Co)) leads to the following set of best-fit parameters: a = 1.28(1), λ = -160(5) cm~(-1) and |?| = 400(20) cm~(-1). The magnetic properties of 2 show the occurrence of a strong antiferromagnetic interaction between the two local spin doublets which lead to a ground singlet spin state [J = -315(2) cm~(-1), the Hamiltonian being defined as H = -JS_A·S_B]. This value is in the upper range of those previously reported for the large family of tetracarboxylate-bridged dicopper(II) complexes, the exchange pathway being provided by the four carboxylate bridges in the syn-syn conformation mode.
机译：两种新的式{{Co（Hpcpa）（H_2O）_3] _n·3 / 2nH_2O}（1）和[Cu_2（MeHpcpa）_4（MeOH）_2]·H_2O·3.68 MeOH（2）的金属配合物[H_3pcpa = N合成了-（4-羧基苯基）草酰胺酸和MeH_2pcpa ＝ H_3pcpa的甲基酯衍生物]，并通过X射线衍射确定了它们的结构。图1是由Hpcpa〜（2-）配体桥接的钴（II）离子的中性之字形链，显示出二齿/单齿配位模式。每个钴（II）离子与三个并列放置的水分子六配位，一个Hpcpa〜（2-）配体的两个草酸盐氧和另一个Hpcpa〜（2-）基团的羧酸氧，构成一个有点扭曲的八面体周围。链内钴-钴的分离度为11.326（2）Ω。 2的结构由桨轮型的离散的顺式-顺式四羧酸桥联双铜（II）单元组成，MeHpcpa配体的草酸盐片段不参与配位。每个铜（II）离子在扭曲的方形锥体环境中为五坐标，在基础平面中具有四个羧氧基，在顶端位置具有甲醇分子。二聚体中的铜-铜间隔为2.5974（11）Ω。已在1.9-300 K的温度范围内研究了1和2的磁性。1的磁性对应于具有重要轨道贡献的磁隔离高自旋钴（II）离子。通过哈密顿量分析其磁数据，H =-αλL_（Co）·S_（Co）+？[L_（ZCo〜2）-2/3] +βH（-aL_（Co）+ g_eS_（Co））导致以下一组最佳拟合参数：a = 1.28（1），λ= -160（5）cm〜（-1）和|？| = 400（20）cm〜（-1）。磁性2表明在两个局部自旋双峰之间存在强反铁磁相互作用，从而导致基态单峰自旋态[J = -315（2）cm〜（-1），哈密顿量定义为H =- JS_A·S_B]。该值在四羧酸盐桥联的双铜（II）配合物大家族先前报道的范围的较高范围内，交换途径是由四个羧酸盐桥以syn-syn构象模式提供的。

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