Metal-Biradical Chains from a High-Spin Ligand and Bis(hexafluoroacetylacetonato)copper(II)
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- 作者：Chandrasekar Rajadurai ; Volker Enkelmann ; Vladimir Ikorskii ; Victor I. Ovcharenko ; Martin Baumgarten
- 刊名：Inorganic Chemistry
- 出版年：2006
- 出版时间：November 27, 2006
- 年：2006
- 卷：45
- 期：24
- 页码：9664 - 9669
- 全文大小：368K
- 年卷期：v.45,no.24(November 27, 2006)
- ISSN：1520-510X
文摘
The synthesis, X-ray crystal structure, and magnetic studies of a rare example of organic/inorganic spin hybridclusters extended in infinite ladder-type chain [Cu(C5F6HO2)2]7(C35H35N5O4)2 ([Cu(hfac)2]7(pyacbisNN)2, 2) formedby 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 P
space groupof 2 with the following parameters: a =10.6191(4) Å, b = 19.6384(7) Å, c = 21.941(9) Å, 
= 107.111(7)
, 
= 95.107(8), 
= 94.208(0), Z = 2. Each repeating unit in 2 carries a centrosymmetric cyclic six spin and alinear five spin cluster with four different copper coordination environments having octahedral and square planargeometries. These clusters are interconnected to form infinite chains which are running along the crystallographicb axis. The magnetic measurements show nearly paramagnetic behavior with very small variations over a largetemperature range. The magnetic properties are thus result of complex competitions of many weak ferro- andantiferromagnetic interactions, which appear as small deviations from quite linear 
eff vs T dependence at lowtemperature. At high temperature (300-14 K), antiferromagnetic behavior dominates a little, while at very lowtemperature (14-2 K), a small increase of eff was observed. The magnetic susceptibility data are described by theCurie-Weiss law [
= C/(T - 
)] with the optimal parameters C = 4.32 ± 0.01 emuK/mol and = - 0.6 ± 0.3K, where C is the Curie constant and is the Weiss temperature.
space groupof 2 with the following parameters: a =10.6191(4) Å, b = 19.6384(7) Å, c = 21.941(9) Å, = 107.111(7), = 95.107(8), = 94.208(0), Z = 2. Each repeating unit in 2 carries a centrosymmetric cyclic six spin and alinear five spin cluster with four different copper coordination environments having octahedral and square planargeometries. These clusters are interconnected to form infinite chains which are running along the crystallographicb axis. The magnetic measurements show nearly paramagnetic behavior with very small variations over a largetemperature range. The magnetic properties are thus result of complex competitions of many weak ferro- andantiferromagnetic interactions, which appear as small deviations from quite linear eff vs T dependence at lowtemperature. At high temperature (300-14 K), antiferromagnetic behavior dominates a little, while at very lowtemperature (14-2 K), a small increase of eff was observed. The magnetic susceptibility data are described by theCurie-Weiss law [ = C/(T - )] with the optimal parameters C = 4.32 ± 0.01 emuK/mol and = - 0.6 ± 0.3K, where C is the Curie constant and is the Weiss temperature.