Organic functionalization of silicane with formaldehyde and propanaldehyde

Highlights: • Reactivity of silicane upon radical initiated addition of aldehydes is studied using periodic DFT ab initio calculations. • Thermodynamics and kinetics predict that the addition reaction of aldehydes on silicane is highly probable to occur. • Total energy calculations suggest that the radical initiated addition reaction of aldehydes on silicane is even more favorable in comparison with the H-Si(111) surface. • Aldehydes show enhanced reactivity upon adsorption on silicane in comparison with hydrocarbons. • The self-propagating character of the reaction has been shown. - Abstract: We have studied the addition reaction of aldehydes on silicane by means of periodic density functional theory. The reaction is initiated at a dangling bond, formed by removing a hydrogen atom from the surface. An incoming unsaturated molecule can attach to the surface by reacting with the dangling bond and forming an intermediate carbon radical state. After abstraction of a neighboring H atom, the molecule becomes stable and a new dangling bond is formed. Thermodynamics and kinetics suggest that adsorption is highly probable to occur. Even more, comparisons with the addition reaction of aldehydes on H-Si(111) and the adsorption of hydrocarbons on silicane, suggest that reaction of aldehydes on silicane is even more favorable. This might be explained in terms of the enhanced polar ambient in silicane with respect to the H-Si(111) surface in the first case, and by the higher stability of Si-O bonds with respect to Si-C bonds in the later. Also, calculations suggest that the attachment of a second molecule is also favorable, indicating the possibility of a chain reaction.