Lennard-Jones Intermolecular Potentials for the Description of 6-Membered Aromatic Heterocycles Interacting with the Isoelectronic CO2 and CS2.

Abstract

We have generated Lennard-Jones potentials for the interaction between CX2 (X = O, S) and 11 nitrogen-doped benzene derivatives in different orientations at the M06-2X/def2-tzvpp level as tools to parametrize accurate force fields and to better understand the interaction of these greenhouse gases with heterocyclic building blocks used in the design of capture and detection systems. We find that the most favorable interactions are found between the carbon in CO2 and the main heterocycle in the ring in a parallel orientation, whereas the preferred interaction mode of CS2 is established between sulfur and the π density of the aromatic ring. The fact that the preferences for interaction sites and orientations of CO2 and CS2 are most of the times opposite helps in terms of ensuring the selectivity of these systems in front of these two isoelectronic compounds. The existence of very good linear correlations ( R2 values very close to one) between the number of nitrogen atoms in the heterocyclic ring and the depth of the interaction potential wells opens the door to the use of these results in generating coarse-grained potentials or models with predictive power for use in the design of larger systems.