Cyanide-bridged Fe(III)-Cu(II) complexes: Jahn-Teller isomerism and its influence on the magnetic properties.
Cyanide-bridged Fe(III)-Cu(II) complexes: Jahn-Teller isomerism and its influence on the magnetic properties.
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DOI：
10.1021/ic301122h
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发表时间：
2012-08
影响因子：
4.6
通讯作者：
M. Atanasov;P. Comba;Stefan Helmle
中科院分区：
文献类型：
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作者：
M. Atanasov;P. Comba;Stefan Helmle
我们在这里报道了四种双核氰化物桥联的Fe(III)-Cu(II)配合物的合成和表征，分别基于四齿或五齿双吡啶配体（L(1)或L(2)；双吡啶是3,7-二氮杂双环[3.3.1]壬烷衍生物）与Cu(II)中心配位，以及三齿联吡啶酰胺(bpca)与低自旋配位Fe(III) 位点，氰化物基团构成两个配位球，其中一个在两个金属离子之间桥接。四种结构特征配合物[{Fe(bpca)(CN)(3)}{Cu(L(1)·H(2)O)}]BF(4)、[{Fe(bpca)(CN)(3)}{Cu(L(2))}][Fe(bpca)(CN)(3)]·5H(2)O、 [{Fe(bpca)(CN)(3)}{Cu(L(2)·MeOH)}]PF(6)·MeOH·H(2)O和[{Fe(bpca)(CN)(3)}{Cu(L(2))}]PF(6)·2H(2)O属于不同的结构异构体。最重要的差异是铜（II）中心与氰化物桥的结构和电子强制（伪Jahn-Teller模式的方向）强或弱相互作用。结合实验磁、电子顺磁共振（EPR）、电子光谱数据以及基于配体场理论和密度泛函理论（DFT）的分析，分析了两个中心磁耦合的相关强度。
We report here the synthesis and characterization of four dinuclear cyanide-bridged Fe(III)-Cu(II) complexes, based on a tetra- or a pentadentate bispidine ligand (L(1) or L(2), respectively; bispidines are 3,7-diazabiyclo[3.3.1]nonane derivatives) coordinated to the Cu(II) center, and a tridentate bipyridineamide (bpca) coordinated to the low-spin Fe(III) site, with cyanide groups completing the two coordination spheres, one of them bridging between the two metal ions. The four structurally characterized complexes [{Fe(bpca)(CN)(3)}{Cu(L(1)·H(2)O)}]BF(4), [{Fe(bpca)(CN)(3)}{Cu(L(2))}][Fe(bpca)(CN)(3)]·5H(2)O, [{Fe(bpca)(CN)(3)}{Cu(L(2)·MeOH)}]PF(6)·MeOH·H(2)O, and [{Fe(bpca)(CN)(3)}{Cu(L(2))}]PF(6)·2H(2)O belong to different structural isomers. The most important differences are structurally and electronically enforced (direction of the pseudo-Jahn-Teller mode) strong or weak interactions of the copper(II) center with the cyanide bridge. The related strength of the magnetic coupling of the two centers is analyzed with a combination of experimental magnetic, electron paramagnetic resonance (EPR), electronic spectroscopic data together with a ligand-field theory- and density functional theory (DFT)-based analysis.