Probing Hydrogen-Bonding Properties of a Negatively Charged MoS₂ Monolayer by Powder X‑ray Diffraction and Density Functional Theory Calculations

The contributions of various noncovalent interactions in stabilization of the assembled and delaminated MoS₂–hexamethylenetetramine (HMTA)-layered compound resulted from the assembly of protonated HMTA molecules and negatively charged 1T-MoS₂ monolayers have been considered on the basis of powder X-ray diffraction pattern modeling, density functional theory calculations, and atoms in molecules quantum theory analysis. The structure with HMTA cations involved in NH···S bonding with MoS₂ layers was concluded to be more advantageous than the alternative one with NH···N bonding between the cations. Delamination was demonstrated to essentially influence the hierarchy of interactions and leads to significant strengthening of the NH···S hydrogen bond established between HMTA and the MoS₂ monolayer surface. The method applied in this study for evaluation of the monolayer MoS₂ properties on the basis of the 3D structure of the MoS₂–organic compound is expected to be helpful to gain insights into the interactions occurring in many MoS₂-based systems.