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

Ciprofloxacin (CfH, C 17 H 18 FN 3 O 3 ) crystallizes with 2‐thiobarbituric (H 2 tba) and barbituric acid (H 2 ba) in the aqueous solution to yield salt CfH 2 (Htba)·3H 2 O ( 1 ), salt cocrystal CfH 2 (Hba)(H 2 ba)·3H 2 O ( 2 ), and salt CfH 2 (Hba)·H 2 O ( 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 CfH 2 + ions, and H 2 ba 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.