A New Disilene with π-Accepting Groups from the Reaction of Disilyne RSiSiR (R = Si^<i>i</i>Pr[CH(SiMe₃)₂]) with Isocyanides

The reaction of 1,1,4,4-tetrakis­[bis­(trimethylsilyl)­methyl]-1,4-diisopropyltetrasila-2-yne (1) with tert-butylisocyanide or tert-octylisocyanide produced the corresponding disilyne–isocyanide adducts [RSiSiR­(CNR′)2] (R = SiiPr­[CH­(SiMe3)2]2, R′ = tBu (2a) or CMe2CH2tBu (2b)), which are stable below −30 °C and were characterized by spectroscopic data and, in the case of 2a, X-ray crystallography. Upon warming to room temperature, 2 underwent thermal decomposition to produce 1,2-dicyanodisilene R­(NC)­SiSi­(CN)­R (3) and 1,2-dicyanodisilane R­(NC)­HSiSiH­(CN)­R (4) via C–N bond cleavage and elimination of an alkane and an alkene. The 1,2-dicyanodisilene derivative 3 was characterized by X-ray crystallography.1,1,4,4-四[双(三甲基硅基)甲基]-1,4-二异丙基四硅-2-炔（化合物1）与叔丁基异氰或叔辛基异氰发生反应，生成对应的二硅炔-异氰加合物[RSiSiR(CNR')₂]（其中R = SiiPr[CH(SiMe₃)₂]₂，R'为叔丁基（2a）或CMe₂CH₂tBu（2b））。该类加合物在-30℃以下稳定，通过光谱数据完成表征；针对化合物2a，还借助X射线晶体衍射进行了结构确认。当升温至室温后，化合物2发生热分解，经碳氮键断裂、消除烷烃与烯烃的过程，生成1,2-二氰基二硅烯R(NC)Si=Si(CN)R（3）与1,2-二氰基二硅烷R(NC)HSiSiH(CN)R（4）。1,2-二氰基二硅烯衍生物3同样通过X射线晶体衍射完成了结构表征。