Segizbayev Medet, Tho Nguyen Minh, Gusev Dmitry G, Dmitrienko Anton, Pilkington Melanie, van der Est Art, Nikonov Georgii I
Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada.
Department of Chemistry and Biochemistry, Wilfrid Laurier University, 75 University Ave W, Waterloo, Ontario N2 L 3 C5, Canada.
Chemistry. 2023 Nov 13;29(63):e202301981. doi: 10.1002/chem.202301981. Epub 2023 Oct 5.
The germylone dimNHCGe (dimNHC=diimino N-heterocyclic carbene) reacts with azides N R (R=SiMe or p-tolyl) to furnish the first examples of germanium π-complexes, i. e. guanidine-ligated compounds (dimNHI-SiMe )Ge (NHI=N-heterocyclic imine, R=SiMe ) and (dimNHI-Tol)Ge (R=p-tolyl). DFT calculations suggest that these species are formed by a Staudinger type replacement of dinitrogen in the azide by a nucleophilic germylone, leading to a transient carbene adduct of iminogermylidene. Heating a solution of compound (dimNHI-SiMe )Ge to 70 °C results in extrusion of the iminogermylidene that further aggregates to produce the known [Me SiNGe] tetramer, whereas the imidazolylidene fragment transforms into an unusual heptatriene species that can be considered as a product of carbene insertion into the C-C bond of a pendant Ar substituent at the imidazolylidene nitrogen of the dimNHC. Reaction of (dimNHI-SiMe )Ge with tetrachloro-o-benzoquinone results in the net transfer of a germanium atom and formation of the free diimino-guanidine ligand. This ligand also forms when (dimNHI-SiMe )Ge is treated with azide N (p-Tol), with the germanium product being [(p-Tol)NGe].
锗烯二亚氨基N-杂环卡宾（dimNHC = 二亚氨基N-杂环卡宾）与叠氮化物NR（R = SiMe或对甲苯基）反应，得到了首例锗π-配合物，即胍基配位的化合物（dimNHI-SiMe）Ge（NHI = N-杂环亚胺，R = SiMe）和（dimNHI-Tol）Ge（R = 对甲苯基）。密度泛函理论计算表明，这些物种是通过亲核锗烯对叠氮化物中氮气的施陶丁格型取代反应形成的，生成了亚氨基锗烯的瞬态卡宾加合物。将化合物（dimNHI-SiMe）Ge的溶液加热至70°C，会挤出亚氨基锗烯，其进一步聚集生成已知的[MeSiNGe]四聚体，而咪唑亚基片段则转化为一种不寻常的庚三烯物种，可视为卡宾插入dimNHC咪唑亚基氮上侧链Ar取代基的C-C键的产物。（dimNHI-SiMe）Ge与四氯邻苯醌反应导致锗原子的净转移并形成游离的二亚氨基胍配体。当（dimNHI-SiMe）Ge用叠氮化物N（p-Tol）处理时也会形成这种配体，锗产物为[（p-Tol）NGe]。
