Novel saccharinate-bridged palladium complexes for efficient C-O bond activation displaying promising luminescence properties.
Novel saccharinate-bridged palladium complexes for efficient C-O bond activation displaying promising luminescence properties.
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DOI：
10.1039/c2dt12187e
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发表时间：
2012-03
影响因子：
4
通讯作者：
M. Santana;Rocío García-Bueno;G. García;G. Sanchez;Joaquín García;A. Kapdi;M. Naik;S. Pednekar;José Pérez;L. García;E. Pérez;J. Serrano
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作者：
M. Santana;Rocío García-Bueno;G. García;G. Sanchez;Joaquín García;A. Kapdi;M. Naik;S. Pednekar;José Pérez;L. García;E. Pérez;J. Serrano
描述了单核和双核环化钯（II）配合物与去质子化糖精配体显示不同的配位模式的合成。通过糖精与相应的羟基配合物[{Pd（μ-OH）（C^N）}（2）]（C^N = 2-（2-吡啶基）苯基（Phpy）I; = 7，8-苯并喹啉基（Bzq）II）直接反应合成了新的化合物，其通式为[{Pd（μ-sac）（C^N）}（2）]，其中糖精根1以桥联-NCO-配位模式存在。用中性配体（L =吡啶（py）2、喹啉（quinol）3或吖啶（acrid）4）进行桥分裂，得到了新的单核衍生物，其中糖精盐作为N-单齿配体。配合物I1，I2和II 2的X-射线衍射结构表征证实了所提出的公式。所有配合物在室温下以溶液和固体形式发射。如果与在溶液中的发射相比，在固态中对于络合物I1和II 1在640-680 nm之间的发射特征显著红移。这些宽发射与同时存在的（3）ππ* 和（3）MMLCT跃迁一致，表明存在强的分子内Pd-Pd基态相互作用。二聚体络合物还显示在无膦条件下催化甲苯磺酸香豆酯和芳基硼酸的Suzuki-Miyaura交叉偶联。初步研究表明，钯纳米粒子的参与，这已被进一步研究使用汞滴试验和中毒实验。
The synthesis of mono- and dinuclear cyclometallated palladium(II) complexes with deprotonated saccharinate ligands displaying different coordination modes is described. The new compounds were prepared by direct reaction between saccharine and the corresponding hydroxo-complexes [{Pd(μ-OH)(C^N)}(2)] (C^N = 2-(2-pyridyl)phenyl (Phpy) I; = 7,8-benzoquinolyl (Bzq) II), showing a general formula [{Pd(μ-sac)(C^N)}(2)] with saccharinate 1 displaying a bridging -NCO-coordination mode. Bridge splitting with neutral ligands (L = pyridine (py) 2, quinoline (quinol) 3 or acridine (acrid) 4) yielded new mononuclear derivatives with saccharinate acting as an N-monodentated ligand. Structural characterization by X-ray diffraction of complexes I1, I2 and II2 confirmed the proposed formulae. All complexes emit in the solution and solid state at room temperature. Emission features between 640-680 nm in the solid state for complexes I1 and II1 are significantly red-shifted if compared to the emission in solution. These broad emissions are consistent with the simultaneous presence of (3)ππ* and (3)MMLCT transitions indicating the existence of a strong intramolecular Pd-Pd ground state interaction. The dimeric complexes have also shown to catalyze Suzuki-Miyaura cross-coupling of coumaryl tosylate and aryl boronic acids under phosphine-free conditions. Initial studies suggest the involvement of palladium nanoparticles, which has been further investigated using mercury-drop test and poisoning experiments.