Universität Heidelberg, Anorganisch-Chemisches Institut, D-69120 Heidelberg, Germany.
Inorg Chem. 2011 Aug 1;50(15):6890-901. doi: 10.1021/ic102430a. Epub 2011 Jun 28.
The synthesis and structural analysis (single crystal X-ray data) of two mononuclear ([Cu(L(1))(CN)]BF(4) and Cu(L(3))(CN)) and three related, cyanide-bridged homodinuclear complexes ({Cu(L(1))}(2)(CN)(3)·1.35 H(2)O, {Cu(L(2))}(2)(CN)(3) and {Ni(L(3))}(2)(CN)(3)) with a tetradentate (L(1)) and two isomeric pentadentate bispidine ligands (L(2), L(3); bispidines are 3,7-diazabicyclo[3.3.1]nonane derivatives) are reported, together with experimental magnetic, electron paramagnetic resonance (EPR), and electronic spectroscopic data and a ligand-field-theory-based analysis. The temperature dependence of the magnetic susceptibilities and EPR transitions of the dicopper(II) complexes, together with the simulation of the EPR spectra of the mono- and dinuclear complexes leads to an anisotropic set of g- and A-values, zero-field splitting (ZFS) and magnetic exchange parameters (Cu1: g(z) = 2.055, g(x) = 2.096, g(y) = 2.260, A(z) = 8, A(x) = 8, A(y) = 195 × 10(-4) cm(-1), Cu2: g and A as for Cu(1) but rotated by the Euler angles α = -6°, β = 100°, D(exc) = -0.07 cm(-1), E(exc)/D(exc) = 0.205 for {Cu(L(1))}(2)(CN)(3)·1.35 H(2)O; Cu1,2: g(z) = 2.025, g(x) = 2.096, g(y) = 2.240, A(z) = 8, A(x) = 8, A(y) = 190 × 10(-4)cm(-1), D(exc) = -0.159 cm(-1), E(exc)/D(exc) = 0.080 for {Cu(L(2))}(2)(CN)(3)). Thorough ligand-field-theory-based analyses, involving all micro states and all relevant interactions (Jahn-Teller and spin-orbit coupling) and DFT calculations of the magnetic exchange leads to good agreement between the experimental observations and theoretical predictions. The direction of the symmetric magnetic anisotropy tensor D(exc) in {Cu(L(2))}(2)(CN)(3) is close to the Cu···Cu vector (22°), that is, nearly perpendicular to the Jahn-Teller axis of each of the two Cu(II) centers, and this reflects the crystallographically observed geometry. Antisymmetric exchange in {Cu(L(1))}(2)(CN)(3)·1.35 H(2)O causes a mixing between the singlet ground state and the triplet excited state, and this also reflects the observed geometry with a rotation of the two Cu(II) sites around the Cu···Cu axis.
报告了两个单核([Cu(L(1))(CN)]BF(4)和Cu(L(3))(CN))和三个相关的、氰桥联同双核配合物({Cu(L(1))}(2)(CN)(3)·1.35 H(2)O、{Cu(L(2))}(2)(CN)(3)和{Ni(L(3))}(2)(CN)(3))的合成和结构分析(单晶 X 射线数据)，它们具有一个四齿(L(1))和两个异构五齿双吡啶配体(L(2)、L(3);双吡啶是 3,7-二氮杂双环[3.3.1]壬烷衍生物)。此外，还报道了实验磁性、电子顺磁共振(EPR)和电子光谱数据以及基于配体场理论的分析。双核铜(II)配合物的磁磁化率和 EPR 跃迁的温度依赖性，以及单核和双核配合物的 EPR 光谱的模拟，导致各向异性的 g 和 A 值、零场分裂(ZFS)和磁交换参数(Cu1：g(z)=2.055，g(x)=2.096，g(y)=2.260，A(z)=8，A(x)=8，A(y)=195×10(-4)cm(-1)，Cu2：g 和 A 与 Cu(1)相同，但通过欧拉角α=-6°，β=100°旋转，D(exc)=-0.07 cm(-1)，E(exc)/D(exc)=0.205对于{Cu(L(1))}(2)(CN)(3)·1.35 H(2)O；Cu1，2：g(z)=2.025，g(x)=2.096，g(y)=2.240，A(z)=8，A(x)=8，A(y)=190×10(-4)cm(-1)，D(exc)=-0.159 cm(-1)，E(exc)/D(exc)=0.080对于{Cu(L(2))}(2)(CN)(3))。彻底的基于配体场理论的分析，包括所有微观状态和所有相关的相互作用( Jahn-Teller 和自旋轨道耦合)和磁交换的 DFT 计算，使得实验观察结果与理论预测之间有很好的一致性。{Cu(L(2))}(2)(CN)(3)中对称磁各向异性张量 D(exc)的方向接近于 Cu···Cu 矢量(22°)，即几乎垂直于两个 Cu(II)中心的 Jahn-Teller 轴，这反映了晶体学观察到的几何形状。{Cu(L(1))}(2)(CN)(3)·1.35 H(2)O 中的反铁磁交换导致单重基态和三重激发态之间的混合，这也反映了观察到的几何形状，两个 Cu(II)位点围绕 Cu···Cu 轴旋转。
