1-Piperonylpiperazinium picrate

In the cation of the title salt [systematic name: 4-(2H-1,3-benzodioxol-5-ylmeth­yl)piperazin-1-ium 2,4,6-tri­nitro­phen­o­late], C(12)H(17)N(2)O(2) (+)·C(6)H(2)N(3)O(7) (−), 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 inter­act through N—H⋯O hydrogen bonds and a weak C—H⋯O inter­action. Weak C—H⋯O inter­actions are also observed between the anions, forming R (2) (2)(10) graph-set ring motifs. In addition, a weak centroid–centroid π–π stacking inter­action between the aromatic rings of the cation and the anion, with an inter­centroid distance of 3.7471 (9) Å, contributes to the crystal packing, resulting in a two-dimensional network along (10-1).