| Abstract: | Anhydrous HBH2(CN)2] crystallizes from acidic aqueous solutions of the dicyanodihydridoborate anion. The formation of HBH2(CN)2] is surprising as the protonation of nitriles requires strongly acidic and anhydrous conditions but it can be rationalized based on theoretical data. In contrast, BX(CN)3]? (X=H, F) gives the expected oxonium salts (H3O)BX(CN)3] while (H3O)BF2(CN)2]/HBF2(CN)2] is unstable. HBH2(CN)2] forms chains via N?H???N bonds in the solid state and melts at 54 °C. Solutions of HBH2(CN)2] in the room‐temperature ionic liquid EMIm]BH2(CN)2] contain the (NC)H2BCN?H???NCBH2(CN)]? anion and are unusually stable, which enabled the study of selected spectroscopic and physical properties. (NC)H2BCN?H???NCBH2(CN)]? slowly gives H2 and (NC)H2BCN?BH(CN)2]?. The latter compound is a source of the free Lewis acid BH(CN)2, as shown by the generation of BHF(CN)2]? and BH(CN)2?py. |
