Isolation and X-ray crystal structure of a 2:1 complex between picric acid and dibenzo-24-crown-8; an example of a sandwich structure

Despite the lack of strong intermolecular interactions in solution, picric acid (PicH) forms crystalline 2:1 complexes with both dibenzo-18-crown-6 (DB18C6) and dibenzo-24-crown-8 (DB24C8). An X-ray crystallographic study of 2PicH·DB24C8 reveals a continous layer structure comprising alternate PicH and DB24C8 molecules with stacking of the π-electron-deficient aromatic rings in the PicH molecules and the π-electron-rich aromatic rings in DB24C8 molecules.