Halogenated closo-dodecaborates are very robust and versatile weakly coordinating anions for numerous applications. The introduction of additional substituents, e.g., pseudohalides, allows the tuning of their chemical and physical properties. In this report, the synthesis of the isocyanate-substituted closo-dodecaborates [B₁₂X₁₁(NCO)]^2– (X = H, F–I) was investigated. In an attempt to synthesize the undecahalogenated derivatives, a selective and halogen-dependent reaction yielding boron clusters carrying the functional groups amidinium (−NHCHNMe₂) and formamide (−NHC(O)H) was discovered. The halogenated anions were fully characterized by vibrational and NMR spectroscopy, mass spectrometry, and X-ray diffraction. Salts of the formamide-substituted anion [B₁₂X₁₁(NHC(O)H)]^2– are surprisingly thermally stable in the condensed phase. In contrast, collision-induced dissociation in the gas phase reveals that the isolated dianion [B₁₂X₁₁(NHC(O)H)]^2– in the gas phase preferentially loses water, while the protonated form, which was generated from decomposition of the tetraalkylammonium counterion [B₁₂X₁₁(NHC(O)H)H]⁻, tends to lose carbon monoxide. Possible reaction mechanisms are discussed.

中文翻译：

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未十二卤化的十二硼酸链十二硼酸盐的衍生化 [B12X11NH3]− （X = F–I）：连接异氰酸酯、脒和甲酰胺官能团


卤代十二硼酸盐是非常稳定且用途广泛的弱配位阴离子，适用于多种应用。引入额外的取代基，例如伪卤化物，可以调整它们的化学和物理性质。在本报告中，研究了异氰酸酯取代的十二碳酸盐 [B₁₂X₁₁（NCO）]^2– （X = H， F–I） 的合成。在尝试合成未十二卤化衍生物的过程中，发现了一种选择性和卤素依赖性反应，产生了携带官能团脒 （−NHCHNMe₂） 和甲酰胺 （−NHC（O）H） 的硼簇。通过振动和 NMR 波谱、质谱和 X 射线衍射对卤代阴离子进行了充分表征。甲酰胺取代阴离子的盐 [B₁₂X₁₁（NHC（O）H）^]2– 在缩合相中具有惊人的热稳定性。相反，气相中碰撞诱导的解离表明，气相中的孤立二阴离子 [B₁₂X₁₁（NHC（O）H）^]2– 优先失去水分，而由四烷基铵反离子分解产生的质子化形式 [B₁₂X₁₁（NHC（O）H]H^]- 倾向于损失一氧化碳。讨论了可能的反应机制。