Cooperative Effects between Hydrogen Bonds and C=O•••S Interactions in the Crystal Structures of Sulfoxides

We report herein a comprehensive structural and computational study of noncovalent interactions between a carbonyl group and the sulfur atom of a sulfoxide group. Two main interaction topologies, each of them following precise geometrical parameters, have been unveiled after the analysis of hundreds of crystal structures. The analysis of experimental crystal structures has been accompanied by DFT calculations on simple systems in order to understand the factors that affect the interaction strength. We have seen that both interaction geometries are attractive and present different contributions from electrostatics and charge transfer to the total interaction energy. In all cases, cooperative effects involving hydrogen bonds, with the sulfoxide acting as the hydrogen bond acceptor, play an important role in the energy stabilization. Moreover, natural bond orbital and energy decomposition analysis have been performed to shed light into the physical origin of these noncovalent interactions.

Automated summary

The study revealed two main geometric topologies of noncovalent interactions between a carbonyl group and the sulfur atom of a sulfoxide group, with different contributions to the total interaction energy from electrostatics and charge transfer. Hydrogen bonds, with the sulfoxide acting as the hydrogen bond acceptor, played a crucial role in energy stabilization in all cases. Natural bond orbital and energy decomposition analysis were performed to understand the physical origin of these noncovalent interactions.