Hydrothermal synthesis, experimental and theoretical characterization of a novel cocrystal compound in the 2:1 stoichiometric ratio containing 6-methyluracil and dipicolinic acid

This paper reports the hydrothermal synthesis, experimental and theoretical studies of a novel cocrystal compound in the 2:1 stoichiometric ratio of 6-methyluracil (6mu) and dipicolinic acid (pydcH2) formulated as [6mu]2[pydcH2] (1), for the first time. DFT calculations were performed to access the most possible geometry of the title cocrystal compound. All calculations were carried out with the B3LYP hybrid density functional level and 6-311+G(d,p) basis sets. The vibrational frequencies together with the 1H and 13C NMR chemical shifts have been calculated on the fully optimized geometry of 1. The theoretical results are in good agreement with the experimental and solution data. The theoretical, solution, and experimental (elemental analysis, mass spectrometry, FTIR, 1H and 13C NMR spectroscopies) results confirmed our proposed structure for 1 in the 2:1 stoichiometric ratio of 6mu and pydcH2, respectively. The protonation and equilibrium constants of 6mu and pydcH2 and constituent systems were determined by potentiometric studies and the corresponding distribution diagrams depicted.

Graphical abstractThis paper reports the hydrothermal synthesis, experimental and theoretical studies of a novel cocrystal compound in the 2:1 stoichiometric ratio of 6-methyluracil (6mu) and dipicolinic acid (pydcH2) formulated as [6mu]2[pydcH2], for the first time.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► A novel cocrystal compound in the 2:1 stoichiometric ratio of 6-methyluracil and dipicolinic acid is hydrothermally synthesized. ► Its chemical structure is studied in views of both solid and solution states.