Koolhaas G. J. Anthony A., Driessen Willem L., Reedijk Jan, van Der Plas Jacob L., de Graaff Rudolf A. G., Gatteschi Dante, Kooijman Huub, Spek Anthony L.
Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
Inorg Chem. 1996 Mar 13;35(6):1509-1517. doi: 10.1021/ic951128y.
The synthesis and characterization of three dinuclear copper(II) complexes and one mixed-valence tetranuclear cluster with the asymmetric imidazole-containing ligand bis(1,1'-imidazole-2-yl)(4-imidazole-4(5)-yl)-2-azabutane (biib) are described. X-ray crystallographic parameters for the copper complexes are as follows. Cu(2)(biib)(2)(BF(4))(2)(2)(H(2)O)(4): triclinic, space group P&onemacr;, a = 10.178(1) Å, b = 9.4881(9) Å, c = 11.037(1) Å, alpha = 95.130(10) degrees, beta = 112.20(1) degrees, gamma = 92.142(9) degrees, and Z = 1. Cu(2)(biib)(2)(NO(3))(2)(2)(H(2)O)(4): monoclinic, space group &Pmacr;2(1)/n, a = 9.207(6) Å, b = 17.0516(6) Å, c = 12.6107(7) Å, beta = 109.82(1) degrees, and Z = 2. [Cu(2)(biib)(2)(CuBr(3))(2)]: monoclinic, space group P2(1)/c, a = 11.583(2) Å, b = 11.864(2) Å, c = 16.070(2) Å, beta = 112.459(12) degrees, and Z = 2. The two Cu(II) ions in all four complexes are coordinated in a square-pyramidal geometry by three imidazole nitrogens and one amine nitrogen donor in the equatorial plane, and each copper ion is weakly coordinated at the axial position by respectively a tetrafluoroborate, a perchlorate, a nitrate, or a tribromocuprate(I) anion. By comparison of the structural data of the four complexes a relationship has been established between the donor strength of the anion and some structural features, like the Cu(II)-Cu(II) distance, of the dinuclear Cu(II)-Cu(II) unit in the four complexes. Single-crystal EPR spectra of Cu(2)(biib)(2)(BF(4))(2)(2)(H(2)O)(4) were recorded at room temperature at X-band frequencies. The triplet spectra have been fit with nonparallel g and D tensors, whose principle values are as follows: g(xx)() = 2.022(8), g(yy)() = 2.060(7), g(zz)() = 2.211(8), D(x)()(')(x)()(') = -0.0182(9) cm(-)(1), D(y)()(')(y)()(') = -0.081(6) cm(-)(1), D(z)()(')(z)()(') = 0.0264(7) cm(-)(1). The compounds were further characterized and studied by ligand field and by frozen-solution and polycrystalline powder EPR spectroscopy. EPR spectra recorded at 77 K of frozen solutions of the perchlorate complex show that upon dilution in methanol the dinuclear complex reacts to form a mononuclear species.
描述了三种双核铜（II）配合物和一种含不对称咪唑配体双（1,1'-咪唑-2-基）（4-咪唑-4（5）-基）-2-氮杂丁烷（biib）的混合价四核簇合物的合成与表征。铜配合物的X射线晶体学参数如下。Cu₂(biib)₂(BF₄)₂₂(H₂O)₄：三斜晶系，空间群P&onemacr;，a = 10.178(1) Å，b = 9.4881(9) Å，c = 11.037(1) Å，α = 95.130(10)°，β = 112.20(1)°，γ = 92.142(9)°，Z = 1。Cu₂(biib)₂(NO₃)₂₂(H₂O)₄：单斜晶系，空间群&Pmacr;2(1)/n，a = 9.207(6) Å，b = 17.0516(6) Å，c = 12.6107(7) Å，β = 109.82(1)°，Z = 2。[Cu₂(biib)₂(CuBr₃)₂]：单斜晶系，空间群P2(1)/c，a = 11.583(2) Å，b = 11.864(2) Å，c = 16.070(2) Å，β = 112.459(12)°，Z = 2。所有四种配合物中的两个Cu（II）离子在赤道平面上由三个咪唑氮和一个胺氮供体以四方锥几何构型配位，并且每个铜离子在轴向位置分别由一个四氟硼酸根、一个高氯酸根、一个硝酸根或一个三溴铜（I）阴离子弱配位。通过比较四种配合物的结构数据，在阴离子的供体强度与四种配合物中双核Cu（II）-Cu（II）单元的一些结构特征（如Cu（II）-Cu（II）距离）之间建立了关系。Cu₂(biib)₂(BF₄)₂₂(H₂O)₄的单晶EPR光谱在室温下于X波段频率记录。三重态光谱已用非平行的g和D张量拟合，其主值如下：g(xx)() = 2.022(8)，g(yy)() = 2.060(7)，g(zz)() = 2.211(8)，D(x)()(')(x)()(') = -0.0182(9) cm⁻¹，D(y)()(')(y)()(') = -0.081(6) cm⁻¹，D(z)()(')(z)()(') = 0.0264(7) cm⁻¹。通过配体场以及冷冻溶液和多晶粉末EPR光谱对这些化合物进行了进一步表征和研究。高氯酸根配合物冷冻溶液在77 K下记录的EPR光谱表明，在甲醇中稀释时，双核配合物反应形成单核物种。
