The N-heterocyclic germylenes and stannylenes LSi(NAr)₂EX (L = PhC(NtBu)₂, Ar = 2,6-iPr₂C₆H₃; E = Ge, Sn; X = Cl, CF₃SO₃, BPh₄) supported by the bulky silaamidinate ligand [LSi(NAr)₂]⁻ have been synthesized and fully characterized. The germylene triflate LSi(NAr)₂GeOTf (3b) and dimeric borate [LSi(NAr)₂Ge]₂ClBPh₄ (3a) enabled highly regio- and chemoselective catalytic hydroboration of pyridines and may represent the most active catalytic system for the transformation. DFT calculations disclosed that the cationic germylene [LSi(NAr)₂Ge]⁺ with a low-lying LUMO energy initiated the catalytic process. In contrast, the analogous amidinate germylene triflates are almost inactive, indicating the silaamidinate ligand is essential for the stabilization of cationic species.

中文翻译：

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阳离子硅酰胺基二甲亚锡和亚锡的合成及其在吡啶硼氢化反应中的催化应用

N-杂环亚锗烷基和亚锡烷基 LSi(NAr) ₂ EX (L = PhC(N t Bu) ₂ , Ar = _2,6 - i Pr ₂ C ₆ H ₃ ; E = Ge, Sn; X = Cl, CF ₃ SO ₃ , BPh ₄ ) 由庞大的硅酰胺配体[LSi(NAr) ₂ ] ^{- 支持，}已被合成并充分表征。锗烯三氟甲磺酸盐 LSi(NAr) ₂ GeOTf ( 3b ) 和二聚硼酸盐 [LSi(NAr) ₂ Ge] ₂ ClBPh ₄ ( 3a) 实现了吡啶的高度区域选择性和化学选择性催化硼氢化反应，并且可能代表最活跃的转化催化系统。DFT 计算表明，具有低位 LUMO 能量的阳离子锗烯 [LSi(NAr) ₂ Ge] ⁺引发了催化过程。相比之下，类似的脒二甲撑三氟甲磺酸酯几乎没有活性，这表明硅脒配体对于稳定阳离子物质是必不可少的。