Determination of the number of unpaired electrons in metal-complexes. A comparison between the Evans' method and susceptometer results
Determination of the number of unpaired electrons in metal-complexes. A comparison between the Evans' method and susceptometer results
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DOI：
10.1016/j.chemphys.2005.04.022
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发表时间：
2005-08-29
期刊：
影响因子：
2.3
通讯作者：
Van Driessche, I
中科院分区：
文献类型：
--
作者：
De Buysser, K;Herman, GG;Van Driessche, I
1，4，8，11-四氮杂环十四烷（cyclam）作为螯合重金属离子（如Ni 2+和Cu 2+）的理想配体而广为人知。在这项工作中，螯合的后果对高自旋或低自旋配置的偏好进行了研究Fe 3+，Ni 2+，Cu 2+和Cr 3+。用两种方法测定了配合物中的未成对电子数。首先，测量了结晶粉末的磁化率变化作为温度升高的函数的依赖性。在第二种情况下，埃文斯的方法被用来获得有关的溶解的络合物中受损的电子的数量的信息。在某些情况下，如Fe 3+和Ni 2+，注意到两种方法获得的结果之间的差异。结果受络合物的几何形状、聚集态和离子的尺寸的影响。(C)2005 Elsevier B. V.保留所有权利。
1,4,8,11-Tetraazacyclotetradecane (cyclam) is widely known as an ideal ligand for chelating heavy metal ions such as Ni2+ and Cu2+. In this work, the consequences of chelation on the preference for high spin or low spin configuration were investigated for Fe3+, Ni2+, Cu2+ and Cr3+. Two methods were used to determine the number of unpaired electrons in the complex. First the dependence of magnetic susceptibility change of the crystalline powder as a function of temperature increase was measured. In the second case, the Evans' method was used to obtain information about the number of impaired electrons in the dissolved complexes. In some cases, such as Fe3+ and Ni2+, a discrepancy between the results obtained with the two methods was noticed. The results are influenced by the geometry of the complex, the aggregation state and the dimensions of the ions. (C) 2005 Elsevier B.V. All rights reserved.