Interaction of acetonitrile with trifluoromethanesulfonic acid: unexpected formation of a wide variety of structuresElectronic supplementary information (ESI) available: Tables and spectra. See DOI: 10.1039/c2ob06841a

Interaction of acetonitrile with trifluoromethanesulfonic acid has been studied by multinuclear NMR and ESI-MS. It has been found that the interaction results in formation of a great variety of different cations and neutral compounds which is controlled by the ratio of CH 3 CN to TfOH. In the presence of an excess of the acid (molar ratio 1:814) diprotonated N -acetylacetamidine 1 is formed as the major product, which eventually transforms into protonated acetamidine 3 and acetic acid 4 . At molar ratio of (1:12) diprotonated 2,4-dimethyl-6-methylidene-3 H -1,3,5-triazine 12 , tautomer of the diprotonated trimethyl-s-triazine 11 , becomes the main product at an early stage of the reaction and diprotonated 1-(dimethyl-1,3,5-triazin-2-yl)prop-1-en-2-ol 15 at a later stage. In the case of a large excess of acetonitrile (420:1) trication 17 is formed as a result of the interaction between 11 and 12 along with some oligomers [(CH 3 CN) 3 ] n ( n = 412). Interaction of the two simple compounds, CH 3 CN and TfOH, results in formation of a variety of complicated structures, the composition of the reaction products being a function of the ratio of CH 3 CN to TfOH.