5-(4-Fluorophenyl)-2H-pyrazol-1-ium 2,2,2-trifluoroacetate

Abstract

The title salt, C9H8FN2+·C2F3O2-, crystallizes with two independent cations (A and B) and two independent anions (C and D) in the asymmetric unit. In the cations, the dihedral angles between the benzene and pyrazolium rings are 23.7(3)° in cation A and 1.8(8)° in cation B. In the crystal, each anion links to the two cations via N-H..O hydrogen bonds, forming a U-shaped unit with an R 4 4(14) ring motif. These U-shaped units stack along the a axis and are linked via C-H..O and C-H..F hydrogen bonds, forming slabs lying parallel to (100). Within the slabs there are π-π interactions between the pyrazolium rings [inter-centroid distance = 3.6326(15)Å] and between the benzene rings [inter-centroid distance = 3.7244(16)Å]. In the anions, the F atoms of the trifluoromethyl groups are disordered over two sets of sites, with refined occupancy ratios of 0.58(3):0.42, 0.540(14):0.46(14), and 0.55(2):0.45(2) for anion C, and 0.73(5):0.27(5), 0.63(5):0.37(5), and 0.57(8):0.43(8) for anion D.