Cukiernik Fabio D., Luneau Dominique, Marchon Jean-Claude, Maldivi Pascale
Département de Recherche Fondamentale sur la Matière Condensée, Service de Chimie Inorganique et Biologique, Laboratoire de Chimie de Coordination, URA CNRS 1194, CEA-Grenoble, 17 Rue des Martyrs, 38054 Grenoble Cedex 9, France.
Inorg Chem. 1998 Jul 27;37(15):3698-3704. doi: 10.1021/ic971366o.
The magnetic properties of several mixed-valent diruthenium long-chain carboxylates of general formula Ru(2)(RCO(2))(4)X (X = Cl, DOS, or RCO(2), DOS = dodecyl sulfate, and RCO(2) = linear aliphatic carboxylate or dialkoxy- or trialkoxybenzoate) were studied in the temperature range 6-400 K. All of the compounds exhibit a strong zero-field splitting (D = ca. 75 cm(-)(1)), independent of the nature of the axial anion X or of the equatorial substituent R. In the X = RCO(2) series an intermolecular antiferromagnetic (AF) interaction zJ = ca. -2 cm(-)(1) was found, whereas in the case of an X = DOS analogue, this interaction is very weak (-0.2 cm(-)(1)). The X = Cl series shows three distinct types of interdimer magnetic exchange: very weak, moderate (|zJ| approximately 2 cm(-)(1)), or strong (|zJ| > 10 cm(-)(1)). One representative complex in this series, Ru(2)(C(4)H(9)CO(2))(4)Cl, has been structurally characterized by X-ray crystallography. Crystal data: tetragonal system, space group I&fourmacr;2d, a = 14.137(3) Å, c = 26.246(5) Å, and Z = 8. Examination of the structures and magnetic behaviors suggests that the AF exchange in this series correlates with the Ru-Cl-Ru intermolecular angle; a qualitative explanation in terms of overlap of magnetic orbitals is proposed. Magnetic susceptibility measurements in the columnar mesophase of the mesomorphic congeners indicate that no significant structural change occurs at the crystal-liquid crystal transition.
研究了通式为Ru₂(RCO₂)₄X（X = Cl、十二烷基硫酸根（DOS）或RCO₂，DOS = 十二烷基硫酸根，RCO₂ = 直链脂肪族羧酸根或二烷氧基或三烷氧基苯甲酸根）的几种混合价态二钌长链羧酸盐在6 - 400 K温度范围内的磁性。所有化合物均表现出强烈的零场分裂（D约为75 cm⁻¹），与轴向阴离子X或赤道取代基R的性质无关。在X = RCO₂系列中，发现分子间反铁磁（AF）相互作用zJ约为 -2 cm⁻¹，而对于X = DOS类似物，这种相互作用非常弱（-0.2 cm⁻¹）。X = Cl系列显示出三种不同类型的二聚体间磁交换：非常弱、中等（|zJ|约为2 cm⁻¹）或强（|zJ| > 10 cm⁻¹）。该系列中的一个代表性配合物Ru₂(C₄H₉CO₂)₄Cl已通过X射线晶体学进行了结构表征。晶体数据：四方晶系，空间群I&4macr;2d，a = 14.137(3) Å，c = 26.246(5) Å，Z = 8。对结构和磁行为的研究表明，该系列中的反铁磁交换与Ru-Cl-Ru分子间角度相关；提出了基于磁轨道重叠的定性解释。对介晶同系物柱状中间相的磁化率测量表明，在晶体 - 液晶转变时没有发生明显的结构变化。
