A crystallographic and computational study of the structural disorder and supramolecular organization in new Oxyma-B salts

• Three new Oxyma-B salts with amines have been synthesized and structurally characterized, revealing remarkable supramolecular diversity driven by the anion’s structural adaptability. • Hirshfeld, MEP, QTAIM and NCIPlot analyses establish a clear energetic hierarchy, with strong N–H···O hydrogen bonds dominating crystal packing when present. • When classical hydrogen bonding is weakened, dispersive π···π interactions emerge as decisive structure-directing forces, highlighting Oxyma-B as a versatile crystal engineering synthon. Three new salts of Oxyma-B with DABCO, 1-methylimidazole, and butylamine were synthesized and structurally characterized by single-crystal X-ray diffraction. All salts exhibit well-defined supramolecular architectures governed by distinct hydrogen-bonding motifs and secondary noncovalent interactions. Depending on the amine, Oxyma-B adapts its hydrogen-bonding modes to generate either three-dimensional frameworks or layered assemblies supported by π-related interactions. Hirshfeld surface analysis confirms that O···H/H···O interactions dominate the packing, underscoring the key role of hydrogen-bonding in stabilizing these salts. Positional disorder is observed in two structures; major and minor components were treated independently, showing that hydrogen-bonding motifs and supramolecular connectivity remain flexible and can adapt to disorder, indicating a versatile stacking pattern. Computational analysis successfully rationalized the crystallographic disorder in salts I and III, revealing that the major occupancy forms are stabilized by ancillary CH···O interactions involving alkyl groups, which tip the energetic balance between competing hydrogen-bonding networks. These findings highlight the structural adaptability of Oxyma-B as an anionic building block and its potential in supramolecular design. Density Functional Theory (DFT) calculations were employed to analyze H-bonded and π-stacking interactions, while the Quantum Theory of Atoms in Molecules (QTAIM) framework enabled detailed characterization of discrete H-bonded motifs (synthons). Interaction energies (–1.8 to –18.4 kcal/mol) confirm that directional NH···O,N bonds act as the dominant stabilizing synthons, with weaker CH···O,N interactions playing a secondary yet significant role in defining the supramolecular architecture.