Sildenafil–Resorcinol Cocrystal: XRPD Structure and DFT Calculations
Rafael Barbas, Vineet Kumar, Oriol Vallcorba, Rafel Prohens, Antonio Frontera
Abstract
Herein, the X-ray powder diffraction (XRPD) crystal structure of a new Sildenafil cocrystal is reported, where resorcinol has been used as the coformer. The crystal structure has been solved by means of direct space methods used in combination with density functional theory (DFT) calculations. In the structure, the Sildenafil and resorcinol molecules form cooperative hydrogen bond (HB) and π-stacking interactions that have been analyzed using DFT calculations, the molecular electrostatic potential (MEP) surface, and noncovalent interaction plot (NCI plot). The formation of O–H⋯N H-bonds between resorcinol and Sildenafil increases the dipole moment and enhances the antiparallel π-stacking interaction.