Donor–Acceptor Stabilized Tetra(silanimine)

The synthesis of an oligo­(silanimine) is described. The reaction of the amidinato silylene [LSiN­(SiMe₃)₂] (1, L = PhC­(NtBu)₂) with SiI₄ in toluene afforded a mixture of the silanimine [LSi­(I)­NSiI₃] (2), SiMe₃I, and Si₂I₆. The mechanistic studies showed that 1 reacts with SiI₄ to form the silyl ionic intermediate “{LSi­(I)­N­(SiMe₃)₂}⁺{SiI₃}⁻”, which then eliminates SiMe₃I and “SiI₂” to form the silanimine intermediate “LSi­(I)­NSiMe₃”. It further undergoes a substitution with another molecule of SiI₄ to form a mixture of 2 and SiMe₃I. In addition, “SiI₂” undergoes an oxidative addition with SiI₄ to form Si₂I₆. Subsequently, compound 2 reacted with [LiN­(SiMe₃)­Ar] to form the silanimine [LSi­(I)­NSiI₂N­(SiMe₃)­Ar] (6, Ar = 2,6-iPr₂C₆H₃), which was then treated with KC₈ to give the donor–acceptor stabilized tetra­(silanimine) [LSiN­(SiMe₃)­SiNAr]₂ (7). It comprises four formal silanimine “>SiN-” units, which are linked together. Compounds 2, 6, and 7 were characterized by NMR spectroscopy and X-ray crystallography.