Effect of the metal-assisted assembling mode on the redox states of hexaazatriphenylene hexacarbonitrile
Effect of the metal-assisted assembling mode on the redox states of hexaazatriphenylene hexacarbonitrile
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DOI：
10.1002/anie.200462962
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发表时间：
2005-01-01
影响因子：
16.6
通讯作者：
Kitagawa, S
中科院分区：
文献类型：
--
作者：
Furukawa, S;Okubo, T;Kitagawa, S
金属导向的自组装通过几个分子识别事件的多齿配体与一个合适的安排的结合位点提供了一种途径，自发但可控的超分子结构的产生。[1]特别是，具有氧化还原活性单元的无机超分子的性质对于它们在传感器，[2]机器，[3]和电子设备中的应用潜力具有强烈的兴趣。[4]然而，少得多的是已知的同时控制这两个组件和这些单位的氧化还原状态。具有低π* 轨道的有机氰化物是特别有希望的氧化还原活性单元的候选者，因为它们的特征电子结构基于不同的、容易获得的氧化态（中性和阴离子自由基态），并且产生迷人的导电和磁性材料。[5]此外，这些π-接受分子的金属导向方法不仅具有合理的自下而上的构建的优点，其调节的配位几何形状，而且在影响配体中心的氧化还原电位方面也起着重要作用。在金属/π配体体系中，络合作用的净电荷转移起作用。这种转移产生了“正常”效应，[6]由于配位的σ-极化效应，导致了大的阳极位移。[7]然而，强π反馈经常发生，并且过度补偿σ-极化效应，从而提供阴极位移。[8]因此，我们专注于通过金属定向自组装来控制配体的氧化态。在接受π的有机氰化物中，hat-（CN）6是一种有趣的分子单元[9，10]，因为其特征性的缺电子杂环核，提供了三种可逆的氧化还原转变以及两种可能的配位模式：联吡啶螯合位点（bpy位点）和末端腈N-结合位点（CN位点，图1）。在此，我们报告两个超分子的
Metal-directed self-assembly through several molecular recognition events on polydentate ligands with a suitable arrangement of binding sites has provided a route for the spontaneous but controlled generation of supramolecular architectures.[1] In particular, the properties of inorganic supramolecules with redox-active units are of intense interest with respect to their potential for application in sensors,[2] machines,[3] and electronic devices.[4] However, much less is known about the simultaneous control of both the assembly and the redox-state of these units. Organocyanides with lowlying π* orbitals are particularly promising candidates for redox-active units because of their characteristic electronic structures, which are based on different, readily accessible oxidation states (neutral and anion radical states) and give rise to fascinating conductive and magnetic materials.[5] In addition, a metal-directed approach with these π-accepting molecules has the advantage not only of rational bottom-up construction, with its regulated coordination geometry, but also plays an important role in influencing the ligand-centered redox potential. A net charge transfer on complexation operates in metal/π ligand systems. This transfer gives rise to the “normal” effect,[6] which causes a large anodic shift because of the σ-polarization effect of coordination.[7] However, strong π back donation often occurs and overcompensates the σ-polarization effect, thus affording a cathodic shift.[8] Hence, we have focused on controlling the oxidation states of the ligand through metal-directed self-assembly. Among the π-accepting organocyanides, hexaazatriphenylene hexacarbonitrile hat-(CN) 6 is an intriguing molecular unit [9, 10] because of its characteristic electron-deficient heterocyclic core, which affords three reversible redox transitions as well as two possible modes of coordination: the bipyridine chelating (bpy sites) and the terminal nitrile N-binding sites (CN sites, Figure 1). Herein, we report two supramolecules of