Speaker
Description
Co-crystallization is a powerful tool in crystal engineering, enabling modification of material and drug properties. While single-crystal methods dominate, many systems crystallize only as powders, requiring alternative approaches. We synthesized the caffeine–oxalic acid cocrystal and applied high-resolution powder X-ray diffraction (PXRD) with computational analysis to assess phase formation, crystallinity, and supramolecular organization. PXRD data were collected on a Bruker D2 diffractometer and analyzed using Diffrac.EVA, Topas, EXPO2014, and DASH, with structural models derived from the Cambridge Structural Database. Thermal analysis (TGA/DSC) was performed to evaluate hydration, phase purity, and decomposition.
PXRD profiles confirmed successful co-crystal formation, distinct from starting materials. Thermal analysis indicated no hydration, with decomposition beginning at 200 °C. Indexing revealed a monoclinic P21/a system consistent with prior reports, with lattice parameters: a = 18.97 Å, b = 14.88 Å, c = 3.27 Å, β = 122.74°. Structure solution via simulated annealing achieved a valid fit (Profile χ² < 2), refined further by Rietveld methods. Hydrogen bonding analysis revealed partial expected interactions, though higher-resolution synchrotron data will be required for full elucidation. This work demonstrates the integrated use of PXRD, computational refinement, and thermal analysis as a practical strategy for investigating co-crystals and inclusion complexes in early-stage solid-form screening.
