Monte Carlo modeling of the enantioselective adsorption of propylene oxide on 1-(1-naphthyl)ethylamine-modified Pt(1 1 1) surfaces

Abstract

Molecular models are proposed to study the enantioselective adsorption of enantiopure propylene oxide (PO) species on platinum surfaces modified by preadsorption of enantiopure 1-(1-naphthyl)ethylamine (NEA) chiral species. This system has been studied experimentally recently [12], and has been found to present a very complex behavior. In this report we show that the observed behavior cannot be explained simply through pair-wise interactions between adsorbed molecules, but rather requires the consideration of cooperative effects arising in some particular local configurations. Starting from a very simple model, kinetic Monte Carlo simulations were used in order to predict the thermal programmed desorption spectra of PO from template surfaces with different NEA coverages. As these predictions were analyzed, more complex conditions were seen to be necessary for a satisfactory reproduction of experimental data. The final model developed in this work does account for many of the trends observed experimentally in the PO + NEA/Pt(1 1 1) system, but is intended to be only a first step toward the understanding of the complex behavior reported at a molecular level. Throughout the development of our model, it was possible to identify some basic necessary conditions in connection with cooperative effects required to reproduce the experimental data.