Md. Ellison et Rj. Hamers, Adsorption of phenyl isothiocyanate on Si(001): A 1,2-dipolar surface addition reaction, J PHYS CH B, 103(30), 1999, pp. 6243-6251
The adsorption of phenyl isothiocyanate (PITC) on silicon (001) surfaces ha
s been investigated using X-ray photoelectron spectroscopy (XPS), Fourier t
ransform infrared (FTIR) spectroscopy, scanning tunneling microscopy (STM),
and ab initio calculations. The experimental evidence shows that adsorptio
n onto the Si surface occurs in a highly selective manner, through the N=C=
S group and not through the benzene ring. Both experimental and theoretical
evidence suggests that the adsorption involves the interaction of the N an
d C atoms of the N=C=S group with the Si=Si dimer, forming a four-member Si
2NC ring at the interface. This process leaves the aromatic ring nearly unp
erturbed and is analogous to a 1,2-dipolar addition reaction. Theoretical c
alculations confirm that this is the most stable product.