Chemical and Structural Features of NMe₂Et Adducts of the Silanimines Me₂Si=NSi<i>t</i>Bu₃ and <i>t</i>Bu₂Si=NSiCl<i>t</i>Bu₂

Abstract

Abstract In contrast to t Bu 2 SiN(Li)SiX t Bu 2 (X = Cl, t Bu), the silyl amide Me 2 SiClN(Li)Si t Bu 3 is unstable towards LiCl elimination, which means that the silanimine donor adduct Me 2 Si=NSi t Bu 3 · NMe 2 Et can be synthesized in high yield from the reaction of Me 2 SiClN(H)Si t Bu 3 with n BuLi inthe presence of NMe 2 Et. The silanimine adduct t Bu 2 Si=NSiCl t Bu 2 · NMe 2 Et, with bulky t Bu substituents at the unsaturated Si center, is accessible by treating the donor‐free silanimine t Bu 2 Si=NSiCl t Bu 2 with NMe 2 Et. X‐rayquality crystals of the silanimine amine adduct Me 2 Si=NSi t Bu 3 · NMe 2 Et (monoclinic, P 2 1 / n ) were grown from pentane at –25 °C. During thermolysis of the adducts Me 2 Si=NSi t Bu 3 · NMe 2 Et and t Bu 2 Si=NSiCl t Bu 2 · NMe 2 Et in NMe 2 Et as solvent a Stevens rearrangement takes place to produce EtN(Me)CH 2 SiMe 2 N(H)Si t Bu 3 and EtN(Me)CH[Me 2 SiN(H)Si t Bu 3 ] 2 , and EtN(Me)CH 2 Si t Bu 2 N(H)SiCl t Bu 2 , respectively. In contrast, the thermolysis of Me 2 Si=NSi t Bu 3 · NMe 2 Et in vacuo gives the silanimine dimer (Me 2 SiNSi t Bu 3 ) 2 (monoclinic, P 2 1 / n ) in 80 % yield. The benzophenone imine Ph 2 C=NSi t Bu 3 (triclinic, P $\bar {1}$ ) was obtained from the Wittig‐like reaction of Me 2 Si=N‐Si t Bu 3 with Ph 2 CO. (© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2006)