Colour tuning by the stepwise synthesis of mononuclear and homo- and hetero-dinuclear platinum(II) complexes using a zwitterionic quinonoid ligand
Colour tuning by the stepwise synthesis of mononuclear and homo- and hetero-dinuclear platinum(II) complexes using a zwitterionic quinonoid ligand
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DOI：
10.1039/c6dt02328b
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发表时间：
2016-01-01
影响因子：
4
通讯作者：
Kato, Masako
中科院分区：
文献类型：
--
作者：
Kar, Paramita;Yoshida, Masaki;Kato, Masako
两性离子配体4 - 甲基氨基 - 6 - 甲基亚氨基 - 3 - 氧代环己 - 1,4 - 二烯 - 1 - 醇盐（QH₂）与[Pt₂(μ - Cl)₂(ppy)₂]（Hppy = 2 - 苯基吡啶）逐步反应，得到单核配合物[Pt(ppy)(QH)]（1）和双核配合物[{Pt(ppy)}₂(μ - Q)]（2）。在第二步中使用[Pd₂(μ - Cl)₂(ppy)₂]导致形成异双核配合物[{Pt(ppy)}(μ - Q){Pd(ppy)}]（3），这是首个由醌型配体桥连的异双核配合物。单晶X射线衍射分析表明，所有三种配合物在晶体中都采用双层结构。对于1，两个相邻的平面正方形单核单元中未配位的N - H和O基团之间的分子间N - H···O相互作用导致形成氢键二聚体，这些二聚体堆积形成具有双层四核基序的人字形结构。对于2和3，由Q²⁻桥连的双核单元形成了与1类似的双层基序，但人字形图案中的四核链是双核配合物的特征。Pt···Pt（或Pt···Pd）距离大于3.5 Å，是Pt的范德华半径的两倍，这表明在晶体结构中金属 - 金属电子相互作用较弱。因此，观察到的不同颜色（1、2和3分别为棕色、紫色和深绿色）主要源于分子结构。实际上，这三种配合物呈现出黄色、红色和绿色的彩色溶液。紫外 - 可见吸收光谱和含时密度泛函理论（TD - DFT）计算表明，颜色变化取决于由金属离子和醌型配体组成的电子态。
The stepwise reaction of a zwitterionic ligand, 4-methylamino-6-methyliminio-3-oxocyclohexa-1,4-dien-1-olate (QH(2)) with [Pt-2(mu-Cl)(2)(ppy)(2)] (Hppy = 2-phenylpyridine) afforded a mononuclear complex, [Pt(ppy)(QH)] (1), and a dinuclear complex, [{Pt(ppy)}(2)(mu-Q)] (2). Using [ Pd-2(mu-Cl)(2)(ppy)(2)] in the second step resulted in the formation of a heterodinuclear complex, [{Pt(ppy)}(mu-Q){Pd(ppy)}] (3), which is the first heterodinuclear complex bridged by a quinonoid ligand. Single crystal X-ray diffraction analysis revealed that all three complexes adopted double-decker structures in the crystal. For 1, intermolecular N-H center dot center dot center dot O interactions between uncoordinated N-H and O groups in two adjacent square-planar mononuclear units led to the formation of hydrogen-bonded dimers, which stacked to form a herringbone structure with a double-decker tetranuclear motif. For 2 and 3, dinuclear units bridged by Q(2) formed a double-decker motif similar to that of 1, but a tetranuclear chain in the herringbone pattern was characteristic of the dinuclear complexes. Pt. Pt (or Pt. Pd) distances were more than 3.5 angstrom, twice the van der Waals radii of Pt, suggesting weak electronic metal-metal interactions in the crystal structures. Thus, the different colours observed (brown, purple, and dark green for 1, 2, and 3, respectively) mainly originated from the molecular structures. In fact, the three complexes exhibited colourful solutions of yellow, red, and green. UV-vis absorption spectroscopy and time-dependent density-functional theory (TD-DFT) calculations revealed that colour variations occurred depending on the electronic states composed of metal ions and the quinonoid ligand.