Synthesis and characterization of imidazolate-bridged polynuclear copper complexes
Synthesis and characterization of imidazolate-bridged polynuclear copper complexes
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DOI：
10.1016/j.ica.2007.03.058
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发表时间：
2007-07
影响因子：
2.8
通讯作者：
Takumi Higa;Masaki Moriya;Y. Shimazaki;T. Yajima;F. Tani;S. Karasawa;M. Nakano;Y. Naruta;O. Yamauchi
中科院分区：
文献类型：
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作者：
Takumi Higa;Masaki Moriya;Y. Shimazaki;T. Yajima;F. Tani;S. Karasawa;M. Nakano;Y. Naruta;O. Yamauchi
合成了含咪唑基团的N4-给体配体4-[双（1-甲基咪唑-2-基-甲基）氨甲基]咪唑（Him-im 2）和4-[双（1-甲基咪唑-2-基-甲基）氨乙基]咪唑（Hhis-im 2）的铜（II）配合物，并通过X射线衍射方法对[Cu（Him-im 2）Cl] ClO 4（1）和[Cu（Hhis-im 2）Cl] ClO 4（2）进行了结构表征。配合物1和2具有单核结构，具有配位的氯离子。1中Cu（II）中心的几何构型为五配位三角双锥构型，而2中Cu（II）中心的几何构型为四方锥构型.配合物1和2在甲醇中表现出不同的吸收光谱和EPR谱，表明这些化合物在溶液中保持了在固态下所揭示的结构。在碱性条件下，Him-im 2与Cu（ClO 4）2·6 H2O反应生成四核Cu（II）配合物[Cu 4（im-im 2）4]（ClO 4）4（3），而与Hhis-im 2反应则生成两种多核配合物[Cu 4（his-im 2）4]（ClO 4）4（4）和[Cu 6（his-im 2）6]（ClO 4）6（5），它们具有不同的结构。多核配合物的X-射线晶体结构分析表明，它们的环状结构由咪唑部分桥接。因此，1和2之间的Cu（II）中心的几何形状的差异，从而确定四核配合物3和4的结构，分别。配合物3、4和5的磁化率随温度变化的测量结果表明它们存在反铁磁交换作用，耦合常数分别为J=−32.5、−27.1和−22.8cm−1。
Copper(II) complexes of N4-donor ligands containing imidazole moieties, 4-[bis(1-methylimidazole-2-yl-methyl)aminomethyl]imidazole (Him-im2) and 4-[bis(1-methylimidazole-2-yl-methyl)aminoethyl]imidazole (Hhis-im2), were prepared, and [Cu(Him-im2)Cl]ClO4(1) and [Cu(Hhis-im2)Cl]ClO4(2) were structurally characterized by the X-ray diffraction method. Complexes 1 and 2 have a mononuclear structure with a coordinated chloride ion. The geometry of the Cu(II) center in 1 was found to be 5-coordinate trigonal-bipyramidal, whereas that of 2 was square-pyramidal. Complexes 1 and 2 showed different absorption and EPR spectra in MeOH, indicating that these compounds in solution maintain the structures revealed in the solid state. On the other hand, the reaction of Him-im2with Cu(ClO4)2·6H2O under basic conditions gave a tetranuclear Cu(II) complex, [Cu4(im-im2)4](ClO4)4(3), whereas using the ligand Hhis-im2gave two kinds of polynuclear complexes [Cu4(his-im2)4](ClO4)4(4) and [Cu6(his-im2)6](ClO4)6(5) exhibiting discretely different structures. X-ray crystal structure analysis of the polynuclear complexes revealed their cyclic structures bridged by the imidazolate moiety. The geometry difference of the Cu(II) centers between 1 and 2 is thus concluded to determine the structures of tetranuclear complexes 3 and 4, respectively. Temperature dependent magnetic susceptibility measurements of complexes 3, 4, and 5 have shown an antiferromagnetic exchange interaction with a coupling constant of J=−32.5, −27.1 and −22.8cm−1, respectively.