Direct Observation of Conformational Isomers of (CH3S)2 Molecules on Cu (111)
Scanning tunneling microscope (STM) images of isolated molecules of dimethyl disulfide, (CH3S)2, adsorbed on a Cu (111) surface were successfully obtained at a sample temperature of 4.7 K. A (CH3S)2 molecule appears as an elliptic protrusion in the STM images. The STM images of (CH3S)2 molecules revealed that the molecules have a total of six equivalent adsorption orientations on Cu (111), which are given by the combination of three equivalent adsorption sites and two conformational isomers for each adsorption site.
We have used IR spectroscopy to study the reaction between L-cysteine and dimethyl sulfoxide in aqueous medium. We have found that reaction occurs with formation of an insoluble product, which we have identified. We show that oxidation of L-cysteine by dimethyl sulfoxide can occur at an appreciable rate under mild conditions, with formation of L-cystine, dimethyl sulfide, and water.