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

Abstract

The covalent attachment of 4-chloroaniline on the Si(111)-7×7 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)-7×7 can be employed for further photochemical modification and functionalization.

Selective Attachment of 4-Bromostyrene on the Si(111)-(7 × 7) Surface

“…Our DFT calculations also showed that the dissociative reaction pathway with the CÀCl bond cleavage (80.4 kJ/mol) has a much higher energy barrier. 9 That may suggest that the cycloaddition reaction through the vinyl group is kinetically favored, which is also consistent with the XPS and HREELS experimental results. The calculated vibrational frequencies (Table I) for model VII are indeed in good agreement with the experimental vibrational spectra of the chemisorbed molecules, which support The Journal of Physical Chemistry C ARTICLE 4-bromostyrene covalently binding to the Si(111) surface through reaction between the vinyl group and the adjacent adatomÀrest atom pair.…”

Dissociative Adsorption of 3-Chloropropyne on Si(111)-(7 × 7): Binding and Structure

“…Since there is only one chemical state of Cl 2p 3/2 positioned at 200.5 eV for physisorbed 3-chloropropyne, this state is attributed to carbon-bound chlorine. The binding energy for Cl 2p 3/2 at 200.5 eV is comparable to the values obtained for physisorbed methyl chloride, 28 ethyl chloride, 29,30 and chlorobenzene 31 on Ag(111), chloriodomethane on Pt(111), 32 1-chloro-2-methyl-2-propanol on Ni(100), 33 and chloroaniline 34 on Si(111) surface. As for the Cl 2p spectrum of chemisorbed 3-chloropropyne, shown in Figure 3b, the binding energy is downshifted by 0.9 to 199.6 eV compared to the physisorbed molecules.…”

“…The feature at 287.3 eV can be attributed to C 3 atom due to its direct bonding with the highly electronegative Cl-atom. The value is close to that of physisorbed CH 3 Cl on Ag(111) 28 and polycrystalline Co. 34 The peak at 285.6 eV is associated with C 1 and C 2 in the HC C-linkage, which is in good agreenment with the value for sp hybridized C atoms in CC group in phenylacetylene, 8 and is close to the binding energy value of physisorbed C 2 H 5 Cl on Ag(111). 29 Figure 4b is the C 1s spectrum for saturated chemisorption monolayer on the Si(111)-(7 × 7) surface obtained by annealing the multilayer 3-chloropropyne covered sample to 300 K to drive away physisorbed molecules but retain chemisorbed ones.…”

Substituent Effects on the Kinetics of Bifunctional Styrene SAM Formation on H-Terminated Si

“…XPS exhibited Cl 2p 1/2 and 2p 3/2 binding energies of 203.3 and 201.7 eV (see Supporting Information SI 3), respectively, which closely match the published Cl 2p 3/2 value of 201 eV in solid chlorobenzene and in 4-chloroaniline bound to Si(111) through the nitrogen. , The Cl peak position is significantly higher than the published value for Cl directly bound to Si (199.5 eV). Thus, the XPS data indicates that chlorostyrene bonds selectively through the alkene.…”