Ishimaru Yoichiro, Kitano Makoto, Kumada Harumi, Koga Noboru, Iwamura Hiizu
Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113, Japan, and Faculty of Pharmaceutical Science and Institute for Fundamental Research of Organic Chemistry, Kyushu University, Fukuoka 812-82, Japan.
Inorg Chem. 1998 May 4;37(9):2273-2280. doi: 10.1021/ic970602s.
Complexes of bis(hexafluoroacetylacetonato)copper(II) [Cu(hfac)(2)] ligated with 3- and 4-(N-oxyl-tert-butylamino)pyridines (3NOPy and 4NOPy) and N-{3- and 4-(N-oxyl-tert-butylamino)phenyl}imidazoles (3NOIm and 4NOIm) were prepared. The 1:2 complexes [Cu(hfac)(2)(3NOPy and 4NOPy)(2)] have hexacoordinated octahedral structures in which the two pyridyl nitrogen atoms are coordinated to the copper(II) ions in the trans configuration. The 1:1 complex [Cu(hfac)(2)(4NOPy)] has a distorted pentacoordinated pseudo-head-to-tail cyclic dimer structure in which the oxygen atom of the aminoxyl group of one complex is situated at a distance of 2.79 Å from the copper ion of the other complex. The magnetic properties of these and two other complexes, [Cu(hfac)(2)(3NOIm and 4NOIm)(2)], were investigated using a SQUID susceptometer. Temperature dependence studies of the chi(mol)Tvalues of [Cu(hfac)(2)(4NOPy)(2)] revealed that the two aminoxyl radicals interact ferromagnetically with the copper(II) ion (S = (1)/(2)) with an exchange parameter J/k(B) = 60.4 +/- 3.3 K to produce a quartet ground state (S = (3)/(2)). On the other hand, the chi(mol)T value of the isomeric [Cu(hfac)(2)(3NOPy)(2)] was nearly constant at 0.5 emu K mol(-)(1) in the temperature range 5-300 K. A rectangular four-spin model was fitted to the chi(mol)T vs T plot for complex [Cu(hfac)(2)(4NOPy)] to give J/k(B) = 58.6 and 58.5 K. Similarly, the J values for [Cu(hfac)(2)(3NOIm and 4NOIm)(2)] were negative and positive, respectively, but their absolute J values were too small to determine in both cases.
制备了双（六氟乙酰丙酮）铜（II）[Cu（hfac）₂]与3-和4-（N-氧基叔丁基氨基）吡啶（3NOPy和4NOPy）以及N-{3-和4-（N-氧基叔丁基氨基）苯基}咪唑（3NOIm和4NOIm）的配合物。1:2配合物[Cu（hfac）₂（3NOPy和4NOPy）₂]具有六配位八面体结构，其中两个吡啶氮原子以反式构型与铜（II）离子配位。1:1配合物[Cu（hfac）₂（4NOPy）]具有扭曲的五配位假头对尾环状二聚体结构，其中一个配合物的氨氧基的氧原子与另一个配合物的铜离子相距2.79 Å。使用超导量子干涉仪（SQUID）磁力计研究了这些配合物以及另外两个配合物[Cu（hfac）₂（3NOIm和4NOIm）₂]的磁性。对[Cu（hfac）₂（4NOPy）₂]的χ（mol）T值进行的温度依赖性研究表明，两个氨氧基自由基与铜（II）离子（S = 1/2）发生铁磁相互作用，交换参数J/kB = 60.4±3.3 K，产生四重基态（S = 3/2）。另一方面，异构体[Cu（hfac）₂（3NOPy）₂]的χ（mol）T值在5-300 K温度范围内几乎恒定在0.5 emu K mol⁻¹。将矩形四自旋模型拟合到配合物[Cu（hfac）₂（4NOPy）]的χ（mol）T对T的图上，得到J/kB = 58.6和58.5 K。同样，[Cu（hfac）₂（3NOIm和4NOIm）₂]的J值分别为负和正，但在两种情况下它们的绝对J值都太小而无法确定。
