Ge(0) Compound Stabilized by a Diimino-Carbene Ligand: Synthesis and Ambiphilic Reactivity

The germylone dimNHCGe
(5, dimNHC = diimino N-heterocyclic
carbene) was successfully prepared via the reduction of the germanium
cation [dimNHCGeCl]+ with KC8. The molecular
structure of 5 was unambiguously established by both
NMR spectroscopy and single-crystal X-ray diffraction. The reactivity
of 5 was investigated, revealing that it undergoes oxidative
addition of HCl, CH3I, and PhI, accompanied by an unusual
migration of the H, Me, and Ph groups from germanium to the carbene
ligand. Related chemistry was also observed with C5F5N, which results in the migration of the fluorinated pyridine
moiety to the carbene ligand. Compound 5 also undergoes
cycloaddition with tetrachloro-o-benzoquinone to
afford a Ge­(IV) adduct.

二亚胺基氮杂环卡宾（diimino N-heterocyclic carbene，缩写dimNHC）配位的锗酮（germylone）类化合物5，可通过八石墨化钾（KC8）还原锗阳离子[dimNHCGeCl]+成功制备。该化合物的分子结构经核磁共振波谱法（NMR spectroscopy）与单晶X射线衍射（single-crystal X-ray diffraction）分析得以明确确证。对化合物5的反应活性进行了考察，结果显示其可与氯化氢（HCl）、碘甲烷（CH3I）及碘苯（PhI）发生氧化加成反应，伴随氢原子、甲基及苯基从锗原子向卡宾配体发生异常迁移。五氟吡啶（C5F5N）与化合物5的反应也呈现出类似的化学行为，即含氟吡啶片段从锗原子迁移至卡宾配体。化合物5还可与四氯邻苯醌（tetrachloro-o-benzoquinone）发生环加成反应，生成四价锗（Ge(IV)）加合物。