“Hot” Surface Activation of Molecular Complexes:Insight from Modeling Studies

The early activation stages of the Cu(hfa)2*TMEDA molecular complex on a hydroxylated silica substrate at high temperature (750 K) have been unraveled by a first-principles molecular dynamics (FPMD) simulation. The hot surface induces significant bond oscillations and interligand interactions on the molecule, which alternates physisorption with low or high molecular mobility. In the spanned simulation time (ca. 30 ps), a novel phenomenon emerged: fast “roll-and-go” diffusion. Such a regime greatly enhances the vibrational excitation of the molecule, increases the probability of highly energetic intermolecular collisions on top of the substrate, and configures itself as a general activation route, which may be operative in a broad variety of processes at hot surfaces.