Griffin Liam P, Ellwanger Mathias A, Clark Jonathon, Myers William K, Roper Aisling F, Heilmann Andreas, Aldridge Simon
Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK.
Angew Chem Int Ed Engl. 2024 May 27;63(22):e202405053. doi: 10.1002/anie.202405053. Epub 2024 Apr 22.
The homoleptic magnesium bis(aluminyl) compound Mg[Al(NON)] (NON=4,5-bis(2,6-diisopropylanilido)-2,7-di-tert-butyl-9,9-dimethylxanthene) can be accessed from K[Al(NON)] and MgI and shown to possess a non-linear geometry (∠Al-Mg-Al=164.8(1)°) primarily due to the influence of dispersion interactions. This compound acts a four-electron reservoir in the reductive de-fluorination of SF, and reacts thermally with polar substrates such as MeI via nucleophilic attack through aluminium, consistent with the QT-AIM charges calculated for the metal centres, and a formal description as a Al(I)-Mg(II)-Al(I) trimetallic. On the other hand, under photolytic activation, the reaction with 1,5-cyclooctadiene leads to the stereo-selective generation of transannular cycloaddition products consistent with radical based chemistry, emphasizing the covalent nature of the Mg-Al bonds and a description as a Al(II)-Mg(0)-Al(II) synthon. Consistently, photolysis of Mg[Al(NON)] in hexane in the absence of COD generates [Al(NON)] together with magnesium metal.
同配双（铝基）镁化合物Mg[Al(NON)]（NON = 4,5-双（2,6-二异丙基苯胺基）-2,7-二叔丁基-9,9-二甲基氧杂蒽）可由K[Al(NON)]和MgI制得，并显示具有非线性几何结构（∠Al-Mg-Al = 164.8(1)°），这主要归因于色散相互作用的影响。该化合物在SF的还原脱氟反应中充当四电子库，并通过铝的亲核进攻与极性底物如MeI发生热反应，这与为金属中心计算的QT-AIM电荷一致，并可形式上描述为Al(I)-Mg(II)-Al(I)三金属化合物。另一方面，在光解活化下，与1,5-环辛二烯的反应导致生成与基于自由基化学一致的跨环环加成产物的立体选择性，强调了Mg-Al键的共价性质，并可描述为Al(II)-Mg(0)-Al(II)合成子。同样，在没有COD的情况下，Mg[Al(NON)]在己烷中的光解会生成[Al(NON)]和镁金属。
