Three 4-(4-fluorophenyl)piperazin-1-ium salts containing organic anions: supramolecular assembly in one, two and three dimensions

Three salts containing the 4-(4-fluorophenyl)piperazin-1-ium cation have been prepared and structurally characterized. In 4-(4-fluorophenyl)piperazin-1-ium 2-hydroxy-3,5-dinitrobenzoate, C₁₀H₁₄FN₂ ⁺·C₇H₃N₂O₇ ^-, (I), the anion contains an intramolecular O-H···O hydrogen bond, and it has a structure similar to that of the picrate ion. The cations and anions are linked into [001] chains of rings by a combination of two three-centre N-H··· (O)₂ hydrogen bonds. The anion in 4-(4-fluorophenyl)piperazin-1-ium hydrogen oxalate, C₁₀H₁₄FN₂ ⁺·C₂HO₄ ^-, (II), is planar, and the cations and anions are linked into (100) sheets by multiple hydrogen bonds including two-centre N-H···O, three-centre N-H.. (O)₂, O-H···O, C-H···O and C-H··· π(arene) types. In 4-(4-fluorophenyl)piperazin-1-ium hydrogen (2R,3R)-tartrate monohydrate, C₁₀H₁₄FN₂ ⁺·C₄H₅O6 ^-·H₂O, (III), the anion exhibits an approximate non-crystallographic twofold rotation symmetry with antiperiplanar carboxyl groups. A combination of eight hydrogen bonds, encompassing two-and three-centre N-H··· O systems, O-H···O and C-H··· π(arene) types, link the independent components into a three-dimensional framework. Comparisons are made with some related structures.