Two salts and the salt cocrystal of ciprofloxacin with thiobarbituric and barbituric acids: The structure and properties

Golovnev, NN; Molokeev, MS; Lesnikov, MK; Atuchin, VV JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, 31 (3):10.1002/poc.3773 MAR 2018

Ciprofloxacin (CfH, C17H18FN3O3) crystallizes with 2‐thiobarbituric (H2tba) and barbituric acid (H2ba) in the aqueous solution to yield salt CfH2(Htba)·3H2O (1), salt cocrystal CfH2(Hba)(H2ba)·3H2O (2), and salt CfH2(Hba)·H2O (3). The compounds are structurally characterized by the X‐ray single‐crystal diffraction. The numerous intermolecular hydrogen bonds N–H⋯O and O–H⋯O formed by water molecules, Htba/Hba and CfH2+ ions, and H2ba molecules stabilize the crystal structures of 1 to 3. Hydrogen bonds form a 2D plane network in the salts of 1 and 3 and a 3D network in the salt cocrystal of 2. There are different π‐π interactions in 1 to 3. The compounds have been characterized by powder X‐ray diffraction, thermogravimetry/differential scanning calorimetry, and Fourier transform infrared spectroscopy. The compounds dehydration ends at 130°C to 150°C, and their oxidative decomposition is observed in the range of 250°C to 275°C.