Density-functional study of the cycloaddition of acrylonitrile on the Si(100) surface

Abstract

Using a density functional approach, we have explored the cycloaddition of acrylonitrile on the Si(100) surface. The buckling of the surface dimers characteristic for the (2x1) reconstructed surface is shown to favor structures with a dipolar moment such as the resonant form of acrylonitrile with cumulative double bonds. The bond of acrylonitrile via a single C atom is a possible intermediate leading to the nitrile structure of the adsorbed molecule.

Chemical manipulation of multifunctional hydrocarbons on silicon surfaces

“…Thus, the buckling of a surface dimer on group IV (100)-2×1 surfaces, including all the electronic and geometrical factors that ultimately define the thermodynamics and kinetics of surface processes plays a deciding role in determining the selectivity of surface reactions. The DFT studies of Cobian et al [155,156] have specifically addressed the reactivity of silicon surface dimers in a context of their buckling and also found a variety of possible products. These authors also compared the theoretical description of the acrylonitrile chemistry with the previous studies of Choi and Gordon [153] and attempted to categorize the total of fifteen different surface configurations considered [156].…”

Dynamic and kinetic aspects of the adsorption of acrylonitrile onSi(001)−2×1

“…1͑a͔͒ has been examined recently both experimentally [6][7][8] theoretically. 6,[9][10][11][12][13] The acrylonitrile/Si͑001͒ system is complex, due to ͑i͒ the presence of two different functionalities and the competition between them, ͑ii͒ the conjugation of the units which allows bond shifts within the molecule, and finally ͑iii͒ the multiple adsorption sites constituted by a pair of dangling bonds on the Si͑001͒-2 ϫ 1 surface ͓Fig. 1͑b͔͒.…”

Thermodynamic factors limiting the preservation of aromaticity of adsorbed organic compounds on Si(100): Example of the pyridine

“…16 and 17) which is a DFT code which solves the Kohn-Sham equations 18 in a plane-waves basis set. Our technical choices are similar to several other lattice calculations devoted to organic molecules adsorbed on Si (100): 13,19,20 -A cutoff energy for the plane-waves basis equal to 450 eV has been used. -The system has been considered at equilibrium when the Hellmann-Feynman forces are smaller than 20 meV/Å.…”

“…Generally, structures with two, three, or four bonds are more stable: for instance, in acrylonitrile, 19,20 the dative bond is far from being the most stable one. Moreover this result is at variance with the lattice calculations of Kim et al, 13 and also with the cluster calculations of Tao et al, 8 who find the mode VIII to be energetically more favorable.…”

“…Following the method used by Cobian et al, 19,20 we have roughly analyzed the different contributions to the calculated heat release for both configurations. This analysis is presented in Fig.…”