Structure and unimolecular chemistry of protonated sulfur betaines, (CH3)2S (CH2)nCO 2H (n = 1 and 2)

Abstract

The fixed charge zwitterionic sulfur betaines dimethylsulfonioacetate (DMSA) (CH3)2S+CH2CO 2- and dimethylsulfoniopropionate (DMSP) (CH 3)2S+(CH2)2CO 2- have been synthesized and the structures of their protonated salts (CH3)2S+CH2CO 2H⋯Cl- [DMSA.HCl] and (CH3) 2S+(CH2)2CO2H⋯ Pcr- [DMSP.HPcr] (where Pcr = picrate) have been characterized using X-ray crystallography. The unimolecular chemistry of the [M+H]+ of these betaines was studied using two techniques; collision-induced dissociation (CID) and electron-induced dissociation (EID) in a hybrid linear ion trap Fourier transform ion cyclotron resonance mass spectrometer. Results from the CID study show a richer series of fragmentation reactio..