Enrofloxacinium picrate.

Abstract

There is one cation–anion pair in the asymmetric unit of the title compound [systematic name: 4-(3-carb­oxy-6-fluoro-4-oxo-1,4-dihydroquinolin-7-yl)-1-ethyl­piperazin-1-ium 2,4,6-tri­nitro­phenolate], C19H23FN3O3 +·C6H2N3O7 −. The six-membered piperazine group in the cation adopts a slightly distorted chair conformation and contains a protonated N atom. The dihedral angles between the mean planes of the cyclo­propyl and piperazine rings in the cation with the 10-atom ring system of the quinolone group are 48.1 (1) and 69.9 (5)°, respectively. The picrate anion inter­acts with the protonated N atom of an adjacent cation through a bifurcated N—H⋯O three-center hydrogen bond, forming an R 1 2(6) ring motif. Furthermore, there is an intra­molecular O—H⋯O hydrogen bond. The dihedral angle between the mean planes of the anion benzene and cation piperizine, quinoline and cyclo­propyl rings are 61.3 (6), 31.1 (4) and 70.4 (9)°, respectively. The mean planes of the two o-NO2 and single p-NO2 groups in the picrate anion are twisted by 6.7 (6), 38.3 (9) and 12.8 (7)° with respect to the mean plane of the benzene ring. Strong N—H⋯O and weak inter­molecular C—H⋯O hydrogen bonds in concert with weak π–π stacking inter­actions [centroid–centroid distances = 3.5785 (13), 3.7451 (12) and 3.6587 (13) Å] dominate the crystal packing.