Synthesis and Crystal Structure of tert‐Butylamino)di‐tert‐butyl)siliceniotrichloroaluminate, (Me₃C)₂SiNCMe₃·AlCl₃, and Dimethylazomethine‐Aluminium Trichloride, Me₂CNH·AlCl₃

Abstract

Lithiated text‐butylaminolfluorosilanes react with aluminum trichloride in ether, eliminating LiF to give AlCl3 adducts of iminosilanes — aminosiliceniotrichloroaluminates {R2Si‐NCMe3·AlCl3}, which thermally form the dimethylazomethine‐ aluminium trichloride, Me2CNH·AlCl3.

First Trichloroaluminum Adducts of Silyliminoborenes

“…With the AlCl 3 adducts of iminosilenes in hands, prepared from lithiated aminofluorosilanes and free iminosilenes [3,6], we investigated the reaction of (Me 3 Si) 2 Compound 1 is the first silylsubstituted iminoborene as well as the first alane adduct of an iminoborene that could be investigated by X-ray diffraction. It can be obtained as a crystalline solid, which is completely inert to dimerization or decomposition if stored under dry nitrogen gas.…”

“…Moreover, the adduct 2 is thermodynamically favored by ∆G = 0.9 kcal mol −1 (from B3LYP/6-311+G(2d,p)). The mechanism for the formation of 1 and 2 most probably consists of two steps: the addition of the Lewis acid to one of the planar amino groups followed by the rate-determining elimination of Me 3 SiF via a four-membered ring transition state. The quantum-chemical investigation of the potential energy surface for this reaction is currently performed in our laboratory.…”

“…BHal 3 , AlCl 3 , AlBr 3 , and GaCl 3 are the preferred reagents for this reaction [1b, c, d] (Eq. 1) which resembles the one applied for the synthesis of phosphenium ions [2] or AlCl 3 adducts of iminosilenes [3]. (1) The B-Hal bond cleavage becomes more difficult with increasing bond strength in the series X = F > Cl > Br > I [1d].…”

From lithiumhalosilylamide to small and large ring compounds, iminosilenes and iminosilanes

“…(11)). Substituting the isopropyl by the bulkier tert-butyl groups, no dicationic cyclosilazane but a monomeric 14 [9] adduct of an iminosilene and trichloroalane is obtained (19) [1,11].…”

“…Such adducts can be distilled without decomposition. Hydrolyses lead to a planar six-membered cyclosiloxane (20) [12] and the tert-butyl-amino-trichloroalane adduct (21) [11] (Eq. (12)):…”