Two-dimensional ferromagnetic intermolecular interactions in crystals of the p-cyanophenyl nitronyl nitroxide radical
Two-dimensional ferromagnetic intermolecular interactions in crystals of the p-cyanophenyl nitronyl nitroxide radical
复制标题
对氰基苯基硝基硝基氧自由基晶体中的二维铁磁分子间相互作用
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
M. Kinoshita
中科院分区：
文献类型：
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作者：
Y. Hosokoshi;M. Tamura;H. Sawa;R. Kato;M. Kinoshita
对氰基苯基硝基氮氧自由基[2-(4-氰基苯基)-4,4,5,5-四甲基-4,5-二氢-1-H-咪唑-1-氧基3-N-氧化物，缩写为p-CNPNN]自由基的晶体结构已被解析。属于斜方晶系，空间群Ic2a，a=10.482(2)A，b=26.615(5)A，c=9.903(2)A，Z=8。不对称单元包含两个独立的自由基分子。氰基苯基和硝基氧基团之间的分子间接触形成准方晶格。在1.8–300 K的温度范围内测量了磁化率。4 K以上的顺磁化率的温度依赖性可以通过J/kB= 0.75 K的铁磁方格海森堡模型来解释。单晶电子顺磁共振（EPR）谱也证实了晶体的二维性。
The crystal structure of the p-cyanophenyl nitronyl nitroxide [2-(4-cyanophenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1-H-imidazol-1-oxyl 3-N-oxide, abbreviated as p-CNPNN] radical has been solved. It belongs to the orthorhombic system, space group Ic2a, with a= 10.482(2)A, b= 26.615(5)A, c=9.903(2)A and Z= 8. The asymmetric unit contains two independent radical molecules. The intermolecular contacts between the cyano phenyl groups and the nitroxide groups form a quasi-square lattice. The magnetic susceptibility has been measured in the temperature range 1.8–300 K. The temperature dependence of the paramagnetic susceptibility above 4 K can be explained by the ferromagnetic squarelattice Heisenberg model with J/kB= 0.75 K. Two-dimensionality of the crystal is also confirmed by single-crystal electron paramagnetic resonance (EPR) spectra.