The concerted and stepwise chemisorption mechanisms of isothiazole and thiazole on Si(100)-2 × 1 surface

The surface reaction pathways of isothiazole and thiazole on Si(100)-2 × 1 surface were theoretically investigated using multireference wavefunctions. In the case of isothiazole, the Si-N dative adduct turned out to be the major surface product. In contrast, a direct reaction competition between a concerted [4 + 2]_CC cycloaddition and Si-N dative adduct was found in the adsorption of thiazole. Therefore, it is concluded that the particular geometric arrangements of heteroatoms exhibit distinctly different initial surface reaction mechanisms.