Self-sorting in two-dimensional assemblies of simple chiral molecules

TL;DR

This study uses a Monte Carlo model to explore how external factors like molecular directors influence chiral self-sorting in 2D assemblies of hockey stick-shaped molecules, revealing conditions that promote segregation.

Contribution

It introduces a coarse-grained Monte Carlo model to analyze the effects of external fields on chiral self-sorting of specific molecules on a lattice, highlighting new insights into molecular ordering.

Findings

Molecular directors significantly affect enantiopure overlayer ordering.

Role of molecular directors is diminished in racemic mixtures.

Temperature and surface coverage influence chiral segregation.

Abstract

Structural modification of adsorbed overlayers by means of external factors is an important objective in the fabrication of stimuli-responsive materials with adjustable physicochemical properties. In this contribution we present a coarse-grained Monte Carlo model of the confinement-induced chiral self-sorting of hockey stick-shaped enantiomers adsorbed on a triangular lattice. It is assumed that the adsorbed overlayer consists of "normal" molecules that are capable of adopting any of the six planar orientations imposed by the symmetry of the lattice and molecular directors having only one permanent orientation, that reflect the coupling of these species with an external directional field. Our investigations focus on the influence of the amount fraction of the molecular directors, temperature and surface coverage on the extent of the chiral segregation. The simulated results demonstrate that the molecular directors can have a significant effect on the ordering in enantiopure overlayers, while for the corresponding racemates their role is largely diminished. These findings can be helpful in designing strategies to improve methods of fabrication of homochiral surfaces and enantioselective adsorbents.