Nickel(II) complexes containing a pyrrole-diphosphine pincer ligand.
Nickel(II) complexes containing a pyrrole-diphosphine pincer ligand.
复制标题
含有吡咯-二膦钳配体的镍(II)络合物。
DOI：
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发表时间：
2012
影响因子：
4.6
通讯作者：
Zachary J. Tonzetich
中科院分区：
文献类型：
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作者：
G. Venkanna;T. Ramos;H. Arman;Zachary J. Tonzetich
以吡咯为原料，经四步反应合成了一种新的钳形配体（P（2）（Ph）Pyr）（-）。该配体在环境条件下氧化为二氧化膦，因此分离为硼烷加合物H（P（2）（Ph）Pyr）·2BH（3）（2）。在Et（2）NH存在下，通过NiCl（2）与2的直接反应来实现配体到镍（II）的传递，得到[NiCl（P（2）（Ph）Pyr）]。通过盐复分解反应得到了新的配合物[Ni（CH（3））（P（2）（Ph）Pyr）]和[Ni（NCCH（3））（P（2）（Ph）Pyr）]（OTf）。在所有情况下，配体都会产生抗磁性方形平面复合物，这些复合物已在溶液和固态中得到充分表征。根据循环伏安法，所有检测的络合物显示不可逆的镍（III）氧化。氯络合物在二氯甲烷中的还原导致电催化过程，而在四氢呋喃中的还原导致镍（I）物质的不可逆形成。
A new pincer ligand, (P(2)(Ph)Pyr)(-), based on the anion of 2,5-bis[(diphenylphosphino)methyl]pyrrole has been prepared in four steps from pyrrole. The ligand undergoes oxidation to diphosphine oxide under ambient conditions and was therefore isolated as its borane adduct, H(P(2)(Ph)Pyr)·2BH(3) (2). Delivery of the ligand to nickel(II) was accomplished by the direct reaction of NiCl(2) with 2 in the presence of Et(2)NH to afford [NiCl(P(2)(Ph)Pyr)]. Salt metathesis reactions of the chloro complex afford new compounds including [Ni(CH(3))(P(2)(Ph)Pyr)] and [Ni(NCCH(3))(P(2)(Ph)Pyr)](OTf). In all cases, the ligand gives rise to diamagnetic square-planar complexes, which have been fully characterized in solution and the solid state. All complexes examined display an irreversible oxidation to nickel(III) according to cyclic voltammetry. Reduction of the chloro complex in dichloromethane results in an electrocatalytic process, whereas reduction in tetrahydrofuran leads to the irreversible formation of a nickel(I) species.