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 â19.5 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 H2 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- A t 400 K. In addition, other surface species of-NCO and >Câ• Câ• O are also observed at 500 K. These species eventually react to generate H2O, CO, CO2, and N2. 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).