Intermolecular interactions, disorder and twinning in ciprofloxacin-2,2-difluoroethanol (2/3) and ciprofloxacin-water (3/14.5).
ABSTRACT The antibiotic ciprofloxacin [systematic name: 1-cyclopropyl-6-fluoro-4-oxo-7-(piperazin-4-ium-1-yl)-1,4-dihydroquinoline-3-carboxylate], has been crystallized as a 2:3 solvate with 2,2-difluoroethanol, 2C(17)H(18)FN(3)O(3)·3C(2)H(4)O(2), (I), and as a 3:14.5 hydrate, 3C(17)H(18)FN(3)O(3)·14.5H(2)O, (II). The structure of (I) was determined using synchrotron X-ray diffraction data and refined as a two-component nonmerohedral twin. Both structures contain several independent molecules in the asymmetric unit: (I) contains two zwitterionic ciprofloxacin molecules and three difluoroethanol solvent molecules, while (II) contains three zwitterionic ciprofloxacin molecules and a mixture of ordered and disordered water molecules. The intermolecular interactions were analysed using fingerprint plots derived from Hirshfeld surfaces, providing a detailed description of the unique environment of each independent ciprofloxacin molecule.