Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, D-07743 Jena, Germany.
Dalton Trans. 2018 Sep 18;47(36):12562-12569. doi: 10.1039/c8dt01539b.
Rubidium bis(trimethylsilyl)amide (rubidium hexamethyldisilazanide, Rb(hmds)) is accessible on a large scale with excellent yields via a magnetite-catalyzed metalation of hexamethyldisilazane (H(hmds)) in liquid ammonia. Recrystallization of solvent-free alkali metal hexamethyldisilazanides [A(hmds)]n of sodium to cesium from solutions containing 2,2,5,5-tetramethyltetrahydrofuran (Me4THF, thf*) yields the dinuclear complexes [(thf*)A(hmds)]2, which show a rather asymmetric coordination behavior of the bulky ether ligand with strongly bent A-A-O moieties for the heavier K, Rb, and Cs congeners, whereas in the Na complex, the ether ligand is clamped between the trimethylsilyl groups. In hydrocarbon solutions, dissociation of these compounds is observed leading to the liberation of this bulky and weakly binding cyclic ether.
双(三甲基硅基)氨基化铷（六甲基二硅基叠氮化铷，Rb(hmds)）可通过磁铁矿催化六甲基二硅氮烷（H(hmds)）在液氨中的金属化作用大规模、高产率地获得。从含有 2,2,5,5-四甲基四氢呋喃（Me4THF，thf*）的溶液中重结晶无溶剂碱金属六甲基二硅氮烷[A(hmds)]n（从钠到铯）得到双核配合物[(thf*)A(hmds)]2，对于较重的 K、Rb 和 Cs 同系物，该配合物显示出大体积醚配体的强烈弯曲 A-A-O 部分的相当不对称配位行为，而在 Na 配合物中，醚配体被夹在三甲基硅基之间。在碳氢化合物溶液中，观察到这些化合物的离解，导致这种大体积和弱结合的环状醚的释放。
