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, C(10)H(14)FN(2) (+)·C(7)H(3)N(2)O(7) (−), (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, C(10)H(14)FN(2) (+)·C(2)HO(4) (−), (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, C(10)H(14)FN(2) (+)·C(4)H(5)O(6) (−)·H(2)O, (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.