Density functional theory study on the dihydrogen bond cooperativity in the growth behavior of dimethyl sulfoxide clusters

TL;DR

This study uses density functional theory to analyze the structure, stability, and cooperative dihydrogen bonding in DMSO clusters, revealing insights into their growth patterns and noncovalent interactions.

Contribution

It provides a detailed quantum chemical analysis of DMSO clusters, highlighting the role of dihydrogen bonds and electrostatic potential in their growth and stability, which is novel.

Findings

DMSO clusters prefer ouroboros-shaped geometries.

Existence of SOC and methyl CHC dihydrogen bonds confirmed.

Linear relationship between hydrogen bonding energy and electron density.

Abstract

We have carried out a density functional theory study on the structures of DMSO clusters and analysed the structure and their stability using molecular electrostatic potential and quantum theory of atoms-in-molecules (QTAIM). The ground state geometry of the DMSO clusters, prefer to exist in ouroboros shape. Pair wise interaction energy calculation show the interaction between methyl groups of adjacent DMSO molecules and a destabilization is is created by the methyl groups which are away from each other. Molecular electrostatic potential analysis shows the existence of hole on the odd numbered clusters, which helps in their highly directional growth. QTAIM analysis show the existence of two intermolecular hydrogen bonds, of type SOC hydrogen bonds and methyl CHC dihydrogen bonds. The computed and Laplacian values were all positive for the intermolecular bonds, supporting the existence of noncovalent interactions. The computed ellipticity for the dihydrogen bonds have values > 2, which confirms the delocalization of electron, are mainly due to the hydrogen-hydrogen interactions of methyl groups. A plot of total hydrogen bonding energy vs the observed total local electron density shows linearity with correlation coefficient of near unity, which indicates the cooperative effects of intermolecular dihydrogen HH bonds.