Twelve 4-(4-meth-oxy-phen-yl)piperazin-1-ium salts containing organic anions: supra-molecular assembly in one, two and three dimensions

Twelve 4-(4-meth-oxy-phen-yl)piperazin-1-ium salts containing organic anions have been prepared and structurally characterized. The monohydrated benzoate, 4-fluoro-benzoate, 4-chloro-benzoate and 4-bromo-benzoate salts, C₁₁H₁₇N₂O⁺·C₇H₅O₂ ^-·H₂O (I), C₁₁H₁₇N₂O⁺·C₇H₄FO₂ ^-·H₂O (II), C₁₁H₁₇N₂O⁺·C₇H₄ClO₂ ^-·H₂O (III), and C₁₁H₁₇N₂O⁺·C₇H₄BrO₂ ^-·H₂O (IV), respectively, are isomorphous and all exhibit disorder in the 4-meth-oxy-phenyl unit: the components are linked by N-H⋯O and O-H⋯O hydrogen bond to form chains of rings. The unsolvated 2-hy-droxy-benzoate, pyridine-3-carboxyl-ate and 2-hy-droxy-3,5-di-nitro-benzoate salts, C₁₁H₁₇N₂O⁺·C₇H₅O₃ ^- (V), C₁₁H₁₇N₂O⁺·C₆H₄NO₂ ^- (VI) and C₁₁H₁₇N₂O⁺·C₇H₃N₂O₇ ^- (VII), respectively, are all fully ordered: the components of (V) are linked by multiple N-H⋯O hydrogen bonds to form a chain of rings; those of (VI) are linked into a three-dimensional framework by a combination of N-H⋯O, C-H⋯O and C-H⋯N hydrogen bonds and those of (VII), where the anion has a structure reminiscent of the picrate anion, are linked into a three-dimensional array by N-H⋯O and C-H⋯O hydrogen bonds. The hydrogensuccinate and hydrogenfumarate salts, C₁₁H₁₇N₂O⁺·C₄H₅O₄ ^- (VIII) and C₁₁H₁₇N₂O⁺·C₄H₃O₃ ^- (IX), respectively, are isomorphous, and both exhibit disorder in the anionic component: N-H⋯O and O-H⋯O hydrogen bonds link the ions into sheets, which are further linked by C-H⋯π(arene) inter-actions. The anion of the hydrogenmaleate salt, C₁₁H₁₇N₂O⁺·C₄H₃O₃ ^- (X), contains a very short and nearly symmetrical O⋯H⋯O hydrogen bond, and N-H⋯O hydrogen bonds link the anions into chains of rings. The ions in the tri-chloro-acetate salt, C₁₁H₁₇N₂O⁺·C₂Cl₃O₂ ^- (XI), are linked into simple chains by N-H⋯O hydrogen bonds. In the hydrated chloranilate salt, 2C₁₁H₁₇N₂O⁺·C₆Cl₂O₄ ^2-·2H₂O (XII), which crystallizes as a non-merohedral twin, the anion lies across a centre of inversion in space group P2₁/n, and a combination of N-H⋯O and O-H⋯O hydrogen bonds generates complex sheets. Comparisons are made with the structures of some related compounds.