Synthesis and Structure of Methylated Acetylenic Nitriles
Dirk Hollenwäger1, Daniela Staudacher1, Niklas Kölbl1
1Department of Chemistry, Ludwig-Maximilian University of Munich (LMU), 81377 Munich, Germany.
Abstract:
Cyanoacetylene and dicyanoacetylene react in the ternary methylation system CH3F/SbF5/SO2 under the formation of its corresponding N-monomethylated and N,N'-dimethylated species, respectively. Additionally, in the case of dicyanoacetylene, an N,N'-dimethylated HF-addition product was obtained. The salts were characterized by low-temperature vibrational spectroscopy. In the case of [C4H4N][SbF6], [C5H3N2][SbF6]·SO2, and [C6H8N2F2][SbF6]2, single-crystal X-ray structures are reported. Surprisingly, all of the obtained salts are room-temperature stable. The experimental data are discussed, together with quantum chemical calculations at the M06-2X/aug-cc-pVTZ level of theory.
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