Selective Dissociation of 4-Chloroaniline on the Si(111)-7x7 Surface through N-H Bond Breakage

The covalent attachment of 4-chloroaniline on the Si(111)-7x7 surface was investigated by using a combination of X-ray photoelectron spectroscopy (XPS), high-resolution electron energy loss spectroscopy (HREELS), and density functional theory (DFT) calculations. The HREELS spectra suggest that one of the N-H bonds dissociates to form Si-N and Si-H bonds with the phenyl ring and the C-Cl bond unperturbed upon chemisorption. The XPS results confirm that only the NH2 group participates in the surface binding. This binding mode and surface reaction pathway are further supported by the DFT calculation. The resulting chlorobenene-like structure on Si(111)-7x7 can be employed for further photochemical modification and functionalization.