Rajadurai Chandrasekar, Enkelmann Volker, Ikorskii Vladimir, Ovcharenko Victor I, Baumgarten Martin
Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128, Mainz, Germany.
Inorg Chem. 2006 Nov 27;45(24):9664-9. doi: 10.1021/ic060197h.
The synthesis, X-ray crystal structure, and magnetic studies of a rare example of organic/inorganic spin hybrid clusters extended in infinite ladder-type chain [Cu(C5F6HO2)2]7(C35H35N5O4)2 ([Cu(hfac)2]7(pyacbisNN)2, 2) formed by the reaction of a high spin nitronylnitroxide biradical C35H35N5O4 (pyacbisNN, 1) and bis(hexafluroacetylacetonate)copper(II) = Cu(hfac)2 are described. Single-crystal X-ray structure analysis revealed the triclinic P1 space group of 2 with the following parameters: a = 10.6191(4) A, b = 19.6384(7) A, c = 21.941(9) A, alpha = 107.111(7) degrees, beta = 95.107(8) degrees, gamma = 94.208(0) degrees , Z = 2. Each repeating unit in 2 carries a centrosymmetric cyclic six spin and a linear five spin cluster with four different copper coordination environments having octahedral and square planar geometries. These clusters are interconnected to form infinite chains which are running along the crystallographic b axis. The magnetic measurements show nearly paramagnetic behavior with very small variations over a large temperature range. The magnetic properties are thus result of complex competitions of many weak ferro- and antiferromagnetic interactions, which appear as small deviations from quite linear mu(eff) vs T dependence at low temperature. At high temperature (300-14 K), antiferromagnetic behavior dominates a little, while at very low temperature (14-2 K), a small increase of mu(eff) was observed. The magnetic susceptibility data are described by the Curie-Weiss law [chi = C/(T - theta)] with the optimal parameters C = 4.32 +/- 0.01 emuK/mol and theta = - 0.6 +/- 0.3 K, where C is the Curie constant and theta is the Weiss temperature.
通过高自旋硝酰基氮氧化物双自由基C35H35N5O4（pyacbisNN，1）与双（六氟乙酰丙酮）铜（II）= Cu（hfac）2反应形成的无限阶梯型链状[Cu（C5F6HO2）2]7（C35H35N5O4）2（[Cu（hfac）2]7（pyacbisNN）2，2）这种有机/无机自旋杂化簇的罕见实例的合成、X射线晶体结构和磁性研究进行了描述。单晶X射线结构分析揭示了2的三斜P1空间群，其参数如下：a = 10.6191（4）Å，b = 19.6384（7）Å，c = 21.941（9）Å，α = 107.111（7）度，β = 95.107（8）度，γ = 94.208（0）度，Z = 2。2中的每个重复单元带有一个中心对称的环状六个自旋和一个线性五个自旋簇，具有四个不同的铜配位环境，具有八面体和正方形平面几何形状。这些簇相互连接形成沿结晶学b轴延伸的无限链。磁性测量表明在很大的温度范围内具有几乎顺磁行为且变化非常小。因此，磁性是许多弱铁磁和反铁磁相互作用复杂竞争的结果，在低温下表现为与相当线性的μ（eff）对T的依赖性有小的偏差。在高温（300 - 14 K）时，反铁磁行为略有主导，而在非常低的温度（14 - 2 K）时，观察到μ（eff）有小的增加。磁化率数据由居里 - 外斯定律[χ = C/（T - θ）]描述，最佳参数为C = 4.32 +/- 0.01 emuK/mol和θ = - 0.6 +/- 0.3 K，其中C是居里常数，θ是外斯温度。
