Investigation of Gas Phase Protonation of 2-Mercaptobenzothiazole; Ion Mobility Spectrometry and DFT calculations

Proton transfer reaction between hydronium ions and 2-Mercatobenzothiazol was investigated in this study using corona discharge-ion mobility spectrometry. Two distinct product ion peaks were observed in the ion mobility spectra with clearly different intensities. Topical proton affinities for two tautomers of 2-Mercatobenzothiazol were theoretically calculated through protonation of all possible sites. Dipole moments of protonated isomers were also used for identification of most probable ionization products. Based on experimental and theoretical results, product ion peaks were assigned to the sulfur protonated isomer of thione form, and nitrogen protonated isomer of thiol form, respectively.