A Soft Grip: Magnesium Complexes with a Phosphine-Modified Phosphonium Diylidic Lewis Base.
A Soft Grip: Magnesium Complexes with a Phosphine-Modified Phosphonium Diylidic Lewis Base.
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DOI：
10.1002/chem.201603775
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发表时间：
2016-11
期刊：
影响因子：
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通讯作者：
J. Langer;Irina Kosygin;R. Puchta;Jürgen Pahl;S. Harder
中科院分区：
文献类型：
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作者：
J. Langer;Irina Kosygin;R. Puchta;Jürgen Pahl;S. Harder
简单的策略，以获得镁配合物与软螯合二亚基配体[Ph 2 PCHPPh 2（芴亚基）]-（dppmflu-）的开发，以评估的影响，硬酸（阳离子）和软碱（阴离子）错配上形成的衍生物的稳定性和反应性。通过烷基镁衍生物或氨基镁将前体Ph 2 PCH 2 PPh 2（flu）（dppmfluH）去质子化提供了[{Mg（dppmflu）（μ-nBu）}2 ]、[Mg（dppmflu）{N（SiMe 3）2 }]和[{Mg（dppmflu）（μ-Me）}2 ]的途径，其用作进一步研究的起始材料。在THF存在下，[{Mg（dppmflu）（μ-nBu）}2 ]与PhSiH 3的反应允许分离氢化镁络合物[{Mg（dppmflu）（μ-H）（thf）}2 ]，而没有稳定的氮供体配体。长时间的加热增强了配体再分布，[{Mg（dppmflu）（μ-H）（thf）}2 ]转化为[Mg（dppmflu）2 ]和MgH 2。均配型衍生物[Mg（dppmflu）2 ]，其中镁中心处于非常软的配体环境中，可以通过受抑的刘易斯对反应性打开THF分子，得到[{Mg（dppmflu）（μ-OC 4 H8 dppmflu）}2 ]。
Simple strategies to obtain magnesium complexes with the soft chelating diylidic ligand [Ph2 PCHPPh2 (fluorenylidene)]- (dppmflu- ) were developed to evaluate the influence of the hard acid (cation) and soft base (anion) mismatch on the stability and reactivity of the formed derivatives. Deprotonation of the precursor Ph2 PCH2 PPh2 (flu) (dppmfluH) by an alkylmagnesium derivative or magnesium amide provided access to [{Mg(dppmflu)(μ-nBu)}2 ], [Mg(dppmflu){N(SiMe3 )2 }], and [{Mg(dppmflu)(μ-Me)}2 ], which were used as starting materials for further investigations. The reaction of [{Mg(dppmflu)(μ-nBu)}2 ] with PhSiH3 in the presence of THF allowed isolation of the magnesium hydride complex [{Mg(dppmflu)(μ-H)(thf)}2 ] without a stabilizing nitrogen donor ligand. Prolonged heating enforced ligand redistribution and [{Mg(dppmflu)(μ-H)(thf)}2 ] was converted to [Mg(dppmflu)2 ] and MgH2 . The homoleptic derivative [Mg(dppmflu)2 ], in which the magnesium center is in a very soft ligand environment, can open a THF molecule by frustrated Lewis pair reactivity to give [{Mg(dppmflu)(μ-OC4 H8 dppmflu)}2 ].