A Dimeric NHC-Silicon Monotelluride: Synthesis, Isomerization, and Reactivity.

The reaction of the NHC-disilicon(0) complex [(IAr )Si=Si(IAr )] (1, IAr =:C{N(Ar)C(H)}2 , Ar=2,6-iPr2 C6 H3 ) with two equiv of elemental Te in toluene at room temperature for three days afforded a mixture of the first dimeric NHC-silicon monotelluride [(IAr )Si=Te]2 (2) and its isomeric complex [(IAr )Si(μ-Te)Si(IAr )=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 [{(IAr )Si(=Te)}2 Te] (5-Te), to form the dimeric NHC-silicon ditelluride [(IAr )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 [{(IAr )Si(=Te)}2 S] (5-S).