1,3-Thiazole on Cu(100) and O/Cu(100): Adsorption and Reaction Pathways

1,3-Thiazole is found to be nearly perpendicularly adsorbed on Cu(100), with the N atom attaching to an atop site and an adsorption energy of similar to 19.5 kcal.mol(-1). The N-C-S moiety of the adsorbed 1,3-thiazole has a larger change in bond length as compared to a free 1,3-thiazole molecule. The adsorbed 1,3-thiazole can decompose below 200 K, forming atomic S and -CHCHNCH-. A small amount of R-S- (R: CHCHNCH) is detected on the surface at 200 K. Complete desulfurization of the 1,3-thiazole occurs at 400 K. Further reaction of the -CHCHNCH- produces H-2 and HCN at higher temperatures. In the presence of adsorbed oxygen atoms(O/Cu(100)), new disulfide intermediates (R-S-S-R, R: CHCHNCH) from the thiazole reaction are measured at 300 K and can further decompose into atomic S and -CHCHNCH- at 400 K. In addition, other surface species of -NCO and >C=C=O are also observed at 500 K. These species eventually react to generate H2O, CO, CO2, and N-2. Further calculations indicate that the S-CHN bond of 1,3-thiazole would break preferentially, as compared to the S-CHCH bond, in the decomposition process on Cu(100).