Low Valent Magnesium Chemistry with a Super Bulky β-Diketiminate Ligand
Low Valent Magnesium Chemistry with a Super Bulky β-Diketiminate Ligand
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DOI：
10.1002/anie.201812051
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发表时间：
2019-01-08
影响因子：
16.6
通讯作者：
Harder, Sjoerd
中科院分区：
文献类型：
--
作者：
Gentner, Thomas Xaver;Roesch, Bastian;Harder, Sjoerd
通过用异丙基取代异戊基，增加了公知的（BDI）-B-DIPP配体（CH[C（CH 3）N-DIPP]（2），DIPP= 2，6-二异丙基苯基）的空间体积。这种非常庞大的（BDI）-B-DIPeP配体不能稳定自由基物质（（BDI）-B-DIPeP）Mg-。用Na还原（（BDI）-B-DIPeP）MgI得到具有3.0513（8）埃的相当长的Mg-Mg键的（（BDI）-B-DIPeP）（2）Mg-2。在还原之前加入TMEDA得到配合物（（BDI）-B-DIPeP）（2）Mg-2（C6 H6），其也可以作为其THF加合物获得。据推测，庞大的旁观者配体和TMEDA的组合防止中间体Mg-I自由基的二聚化，其然后与苯溶剂反应。配合物（（BDI）-B-DIPeP）（2）Mg-2（C6 H6），其形式上含有反芳香阴离子C6 H62-，与tBuOH作为布朗斯台德碱反应生成1，3-和1，4-环己二烯，与H-2作为双电子供体反应生成（（BDI）-B-DIPeP）（2）Mg 2 H2和C6 H6。它还还原裂解氟苯中的C-F键，得到（（BDI）-B-DIPeP）MgPh、（（BDI）-B-DIPeP）MgF和C_6H_6。
The steric bulk of the well-known (BDI)-B-DIPP ligand (CH[C(CH3)N-DIPP](2), DIPP=2,6-diisopropylphenyl) was increased by replacing isopropyl for isopentyl groups. This very bulky (BDI)-B-DIPeP ligand could not stabilize the radical species ((BDI)-B-DIPeP)Mg-.: reduction of ((BDI)-B-DIPeP)MgI with Na gave ((BDI)-B-DIPeP)(2)Mg-2 with a rather long Mg-Mg bond of 3.0513(8) angstrom. Addition of TMEDA prior to reduction gave complex ((BDI)-B-DIPeP)(2)Mg-2(C6H6), which could also be obtained as its THF adduct. It is speculated that combination of a bulky spectator ligand and TMEDA prevents dimerization of the intermediate Mg-I radical, which then reacts with the benzene solvent. Complex ((BDI)-B-DIPeP)(2)Mg-2(C6H6), which formally contains the anti-aromatic anion C6H62-, reacted with tBuOH as a Bronsted base to 1,3- and 1,4-cyclohexadiene and with H-2 as a two electron donor to ((BDI)-B-DIPeP)(2)Mg2H2 and C6H6. It also reductively cleaved the C-F bond in fluorobenzene and gave ((BDI)-B-DIPeP)MgPh, ((BDI)-B-DIPeP)MgF, and C6H6.