Synthesis and Structural Characterization of Ammonio/Hydroxo Undecachloro-closo-Dodecaborates [B12Cl11NH3]-/[B12Cl11OH]2- and Their Derivatives

Anions [B12Cl11NH3](-) and [B12Cl11OH](2-) were prepared in high yields from the known precursors [B12H11NH3](-) and [B12H11OH](2-) by using SO2Cl2. Reaction monitoring by B-11 NMR spectroscopy and ESI-mass spectrometry indicated that SO2Cl2 serves as a convenient chlorination reagent in both transformations. This chemical is an alternative to SbCl5 or chlorine gas, which have been used in reported procedures. [B12Cl11NMe3](-) was prepared in 92% overall yield from [B12H11NH3](-) salts without isolation of the unmethylated intermediate. Starting from [B12Cl11OH](2-), [B12Cl11OS(O)CF3](2-) was obtained unexpectedly by using Tf2O in pyridine/CH2Cl2 by a rare reduction process, while [B12Cl11OTs](2-) was synthesized by using TsCl in pyridine. All compounds were fully characterized by NMR and IR spectroscopy and ESI-mass spectrometry. [Ag(MeCN)(4)][B12Cl11NH3], [Et4N][B12Cl11NH3], [Me4N](2)[B12Cl11OH], [Et3NH][Cs][B12Cl11OH], [Ph3PMe](2)[B12Cl11OS(O)CF3], and [MePPh3](2)[B12Cl11OTs] were studied by X-ray diffraction.