1-Piperonylpiperazinium picrate.

IN THE CATION OF THE TITLE SALT [SYSTEMATIC NAME: 4-(2H-1,3-benzodioxol-5-ylmeth-yl)piperazin-1-ium 2,4,6-tri-nitro-phen-o-late], C12H17N2O2 (+)·C6H2N3O7 (-), the piperazine ring adopts a slightly disordered chair conformation. The piperonyl ring system and the piperazine ring are twisted with respect to each other with an N-C-C-C torsion angle of 40.7†(2)°. In the anion, the dihedral angles between the mean planes of the nitro substituents ortho to the phenolate O atom and the mean plane of the phenyl ring are 28.8†(9) and 32.2†(8)°. In contrast, the nitro group in the para position lies much closer to the aromatic ring plane, subtending a dihedral angle of 3.0†(1)°. In the crystal, the cations and anions inter-act through N-H⋯O hydrogen bonds and a weak C-H⋯O inter-action. Weak C-H⋯O inter-actions are also observed between the anions, forming R 2 (2)(10) graph-set ring motifs. In addition, a weak centroid-centroid π-π stacking inter-action between the aromatic rings of the cation and the anion, with an inter-centroid distance of 3.7471†(9)†à , contributes to the crystal packing, resulting in a two-dimensional network along (10-1).