On the Geometrical Stability of Square‐Planar Platinum(0) Complexes That Bear a PNP‐Pincer‐Type Phosphaalkene Ligand (Eind 2 ‐BPEP)
On the Geometrical Stability of Square‐Planar Platinum(0) Complexes That Bear a PNP‐Pincer‐Type Phosphaalkene Ligand (Eind 2 ‐BPEP)
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关于带有 PNP-钳型磷烯配体 (Eind 2 -BPEP) 的方形平面铂 (0) 配合物的几何稳定性
DOI：
10.1002/chem.201803097
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Ozawa Fumiyuki
中科院分区：
文献类型：
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作者：
Taguchi Hiro‐omi;Tanigawa Ippei;Takeuchi Katsuhiko;Ozawa Fumiyuki
四配位Pt0配合物[Pt(PPh3)(Eind2-BPEP)]（Eind=1,1,3,3,5,5,7,7-八乙基-1,2,3,5,6,7-六氢-s-indacen-4-基；BPEP=2,6-双(1-苯基-2-磷乙烯基)吡啶），其中 具有 PNP 钳型磷烯配体（Eind2-BPEP；PNP=N,N-双（二苯基膦）-2,6-二氨基吡啶），被发现在 Pt 中心周围采用方形平面构型（τ4=0.11）。这种配位几何对于正式的 d10 配合物来说非常罕见。在本研究中，引入了一系列具有不同电子特性的配体（即 DMAP、2,6-二甲基吡啶、PMe3、tBuNC 和 CO）来代替 PPh3，并检查了它们对配位几何的影响。 X射线衍射分析表明，所有配合物均采用方形平面构型（τ4=0.20-0.27）。相反，DFT 计算表明，Pt 周围变形的几何稳定性随配体的不同而变化。具有吡啶基配体的配合物具有刚性的平面结构，而具有π接受配体（例如CO）的配合物对于变形相对灵活。配体的电子效应反映在配合物的光谱特性上，在近红外区域显示出较大的颜色变化。
The four‐coordinate Pt0complex [Pt(PPh3)(Eind2‐BPEP)] (Eind=1,1,3,3,5,5,7,7‐octaethyl‐1,2,3,5,6,7‐hexahydro‐s‐indacen‐4‐yl; BPEP=2,6‐bis(1‐phenyl‐2‐phosphaethenyl)pyridine), which bears a PNP‐pincer‐type phosphaalkene ligand (Eind2‐BPEP; PNP=N,N‐bis(diphenylphosphine)‐2,6‐diaminopyridine), were found to adopt a square‐planar configuration around the Pt center (τ4=0.11). This coordination geometry is very uncommon for formal d10complexes. In this study, a series of ligands with different electronic properties (i.e., DMAP, 2,6‐lutidine, PMe3,tBuNC, and CO) were introduced in place of PPh3, and their effects on the coordination geometry were examined. X‐ray diffraction analysis revealed that all complexes adopted a square‐planar configuration (τ4=0.20–0.27). In contrast, DFT calculations indicated that the geometrical stability towards distortion around Pt varied with the ligand. The complexes with pyridine‐based ligands had rigid planar structures, whereas those with π‐accepting ligands, such as CO, were relatively flexible towards distortion. The electronic effects of the ligands were reflected in the spectroscopic properties of the complexes, which showed a large color change in the near‐infrared region.