Exploring the influence of crystal packing on the optical-physical property of quercetin-based binary and ternary solid forms

The co-crystallization of quercetin (Qur) with a flexible molecule 4-(4-pyridinyldisulfanyl) pyridine (DPDS) in different solvents and conditions was investigated, yielded five multi-component crystalline phases and characterized with X-ray diffractions and thermal analysis. Although the crystal system of Qur-DPDS-MeOH and Qur-DPDS-Dioxane is the same, the desolvation results revealed that Qur-DPDS-MeOH trans-formed to Qur-DPDS when MeOH solvent molecules escape from the lattice, while Qur-DPDS-Dioxane transformed to Qur-DPDS-II through a similar process, which is same with Qur-DPDS-THF. These two cocrystal polymorphs Qur-DPDS and Qur-DPDS-II obey an enantiotropic relationship. Moreover, the for-mation of cocrystal solvates improves the packing efficiency of crystals. Crystal structure analysis showed that hydrogen bonds and conformations of the corresponding parent molecules play a major role in molecular assembly and crystal packing patterns, thus bring different physicochemical properties. Finally, the fluorescence spectra and quantum-chemical calculations were carried out to explore the difference in the optical-physical properties.(c) 2023 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

The co-crystallization of quercetin with a flexible molecule DPDS in different solvents and conditions resulted in five crystalline phases, which were characterized using X-ray diffraction and thermal analysis. The formation of cocrystal solvates improved the packing efficiency of crystals. Hydrogen bonds and conformations of the parent molecules played a major role in molecular assembly and crystal packing patterns, leading to different physicochemical properties. Fluorescence spectra and quantum-chemical calculations were conducted to explore the difference in the optical-physical properties.