Pincers with diverse donors and their interconversion: application to Ni(II)
Pincers with diverse donors and their interconversion: application to Ni(II)
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DOI：
10.1002/zaac.202100064
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发表时间：
2021-07-01
影响因子：
1.4
通讯作者：
Caulton, Kenneth G.
中科院分区：
文献类型：
--
作者：
Cabelof, Alyssa C.;Carta, Veronica;Caulton, Kenneth G.
由邻位被大膦臂和吡唑臂 (PNNH) 取代的吡啶组成的钳式配体安装在镍 (II) 上，产生抗磁性平面配合物 [(PNNH)NiCl]Cl。氯阴离子可通过复分解被 BPh4- 取代。酸性吡唑质子可以用 LiN(SiMe3)(2) 去除，得到方形平面中性分子 (PNN-)NiCl。配位氯化物可以被叠氮化物复分解生成抗磁性 (PNN-)Ni(N-3)。为了评估改变硫化膦的膦供体，合成了相应的钳配体 SPNNH 并将其安装在 NiBr2 上。较远的磷减少的空间体积使两种卤化物在顺磁分子物种 (SPNNH)NiBr2 中保持配位。对该物质脱溴氢的多次尝试导致了两种意想不到的产物的合成和表征。一项研究表明，P(V) 的亲电特性使 (SPNNH)NiBr2 中的磷原子容易受到亲核攻击，从而产生了已表征的 P/C 裂解产物。
A pincer ligand composed of a pyridine with ortho positions substituted by a bulky phosphine arm and a pyrazole arm (PNNH) is installed on nickel(II) to yield the diamagnetic planar complex [(PNNH)NiCl]Cl. The chloride anion can be replaced by BPh4- by a metathesis. The acidic pyrazole proton can be removed with LiN(SiMe3)(2) to yield the square planar neutral molecule (PNN-)NiCl. The coordinated chloride can be metathetically replaced by azide to yield diamagnetic (PNN-)Ni(N-3). To evaluate changing the phosphine donor for a phosphine sulfide, the corresponding pincer ligand SPNNH was synthesized and installed on NiBr2. The reduced steric bulk from the more distant phosphorous keeps both halides coordinated in the paramagnetic molecular species (SPNNH)NiBr2. Several attempts to dehydrobrominate this species result in synthesis and characterization of two unexpected products. One effort revealed that the electrophilic character of P(V) leaves the phosphorus atom in (SPNNH)NiBr2 vulnerable to nucleophilic attack, resulting in a P/C cleavage product which was characterized.