A Dimeric NHC–Silicon Monotelluride: Synthesis, Isomerization, and Reactivity

The reaction of the NHC–disilicon(0) complex [(I_Ar)Si=Si(I_Ar)] (1, I_Ar=:C{N(Ar)C(H)}₂, Ar=2,6-iPr₂C₆H₃) with two equiv of elemental Te in toluene at room temperature for three days afforded a mixture of the first dimeric NHC–silicon monotelluride [(I_Ar)Si=Te]₂ (2) and its isomeric complex [(I_Ar)Si(μ-Te)Si(I_Ar)=Te] (3). When the same reaction was performed for ten days, only 3 was isolated from the reaction mixture. Compound 1 reacted with four equiv of elemental Te in toluene for four weeks, which proceeded through the formation of 2, 3 and the NHC–disilicon tritelluride complex [{(I_Ar)Si(=Te)}₂Te] (5-Te), to form the dimeric NHC–silicon ditelluride [(I_Ar)Si(=Te)(μ-Te)]₂ (4). The reactions are in line with theoretical mechanistic studies for the formation of 4. Compound 3 reacted with one equiv of elemental sulfur in toluene to form the first NHC–disilicon sulfur ditelluride complex [{(I_Ar)Si(=Te)}₂S] (5-S).