Sulfonic Salts of Organic Cations

The FD mass spectra of the di-n-butylammonium salts of a few naphthalene- and anthraquinonesulfonic acids have been reported38. The spectra were dominated by the [Bu2NH2] + ion ([Cat]+). Naphthalene-1-sulfonic acid dibutylammonium salt showed a major [M + Cat] + ion while more abundant ions were [M + H] + in the spectrum of naphthalene-2,6-disulfonic acid di-dibutylammonium salt and [M — Cat + 2H] + in the spectrum of naphthalene-1,3,6-trisulfonic acid tri-dibutylammonium salt. 

By mixing sodium anilinomethanesulfonates 51 with anilinium or p-toluidinium chloride in equimolar ratio, anilinium or p-toluidinium anilinomethanesulfonates 52 were obtained (equation 6)39. Despite their thermal instability at temperatures close to their low melting points, conventional El mass spectra were recorded for compounds 52 and compared with those of compounds 51. 

Very low basicity and nucleophilicity made the trifluoromethanesulfonate anion (TfO ) the counterion of choice for labile cationic species as in dication salts 53 and 54, which were characterized by FD, FAB and 252Cf-Plasma Desorption mass spectrometry40. In the FD mass spectrum of 53, the noteworthy presence of the dication itself ([D]2 + ) was found, giving the base peak, accompanied by a cation triflate cluster [D OTf]+ and fragment ions, involving cleavage at the ether bond. 

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