Alloyed Tetranuclear Metal Chains of Pd4-n Ptn (n=0-3) Scaffolded by a New Linear Tetraphosphine Containing a PNP Bridge.
Alloyed Tetranuclear Metal Chains of Pd4-n Ptn (n=0-3) Scaffolded by a New Linear Tetraphosphine Containing a PNP Bridge.
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DOI：
10.1002/chem.201901701
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发表时间：
2019-05
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通讯作者：
T. Tanase;Miho Tanaka;Mami Hamada;Yuka Morita;Kanako Nakamae;Y. Ura;Takayuki Nakajima
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作者：
T. Tanase;Miho Tanaka;Mami Hamada;Yuka Morita;Kanako Nakamae;Y. Ura;Takayuki Nakajima
合成了一种含PNP磷烷桥的新型线性四膦，rac1 -双[（二苯基膦甲基）苯基膦]苯胺（rac1 -dpmppan），并用于支撑一系列Pd/Pt混合金属四核链，[Pd4-n Ptn (μ-rac-dpmppan)2 (XylNC)2](PF6)2 (XylNC= xyyl异氰酸酯；n=0: Pd4 (1), 1: PtPd3 (2), 2: PtPd2 Pt (3), 2: Pt2 Pd2 (4), 3: Pt2 PdPt(5))，其中额外的Pt原子的数量和位置成功地控制取决于各自的合成过程，通过氧化还原偶联交换反应从1到3到2和从4到5的转化。31 P{1h} NMR和ESI质谱以及x射线衍射分析显示了几乎相同的四核结构，由于Pt原子的结合，金属-金属键略有收缩。1 ~ 5的电子吸收光谱在635 ~ 510 nm处表现出与Pt中心数目和位置有关的能量倾向，理论计算将其归为HOMO （dσ*σσ*）到LUMO （dσ*σ*σ*）跃迁。目前的研究结果表明，钯/铂混合金属四核配合物的电子结构通过原子精确地将铂掺入Pd4链而被精细地调谐为轨道重叠的合金金属链。
A new linear tetraphosphine containing a PNP phosphazane bridge, rac-bis[(diphenylphosphinomethyl)phenylphosphino]phenylamine (rac-dpmppan), was synthesized and utilized to support a series of Pd/Pt mixed metal tetranuclear chains, [Pd4-n Ptn (μ-rac-dpmppan)2 (XylNC)2 ](PF6 )2 (XylNC=xylyl isocyanide; n=0: Pd4 (1), 1: PtPd3 (2), 2: PtPd2 Pt (3), 2: Pt2 Pd2 (4), 3: Pt2 PdPt (5)), in which the number and positions of additional Pt atoms were successfully controlled depending on the respective synthetic procedures using transformations from 1 to 3 through 2 and from 4 to 5 by redox-coupled exchange reactions. The 31 P{1 H} NMR and ESI mass spectra and X-ray diffraction analyses revealed almost identical tetranuclear structures, with slight contraction of metal-metal bonds according to incorporation of Pt atoms. The electronic absorption spectra of 1-5 exhibited characteristic bands at 635-510 nm with an energy propensity depending on the number and positions of Pt centres, which were assigned to HOMO (dσ*σσ*) to LUMO (dσ*σ*σ*) transition by theoretical calculations. The present results demonstrated that the electronic structures of Pd/Pt mixed-metal tetranuclear complexes are finely tuned as orbital-overlapping alloyed metal chains by atomically precise Pt incorporation in the Pd4 chain.