Crystal-structure studies of 4-phenyl­piperazin-1-ium 4-eth­oxy­benzoate monohydrate, 4-phenyl­piperazin-1-ium 4-meth­oxy­benzoate monohydrate, 4-phenyl­piperazin-1-ium 4-methyl­benzoate monohydrate and 4-phenyl­piperazin-1-ium tri­fluoro­acetate 0.12-hydrate

In this study, four new piperazinium salts, namely, 4-phenyl­piperazin-1-ium 4-eth­oxy­benzoate monohydrate, C(9)H(9)O(3)·C(10)H(15)N(2)·H(2)O (I); 4-phenyl­piperazin-1-ium 4-meth­oxy­benzoate monohydrate, C(10)H(15)N(2)·C(8)H(7)O(3)·H(2)O (II); 4-phenyl­piperazin-1-ium 4-methyl­benzoate monohydrate, C(10)H(15)N(2)·C(8)H(7)O(2)·H(2)O (III); and 4-phenyl­piperazin-1-ium tri­fluoro­acetate 0.12 hydrate, C(10)H(15)N(2)·C(2)F(3)O(2)·0.12H(2)O (IV), have been synthesized. The single-crystal structures of these compounds reveal that all of them crystallize in the triclinic P [Image: see text] space group and the crystal packing of (I)–(III) is built up of ribbons formed by a combination of hydrogen bonds of type N—H⋯O, O—H⋯O and other weak inter­actions of type C—H⋯O and C—H⋯π, leading to a three-dimensional network. In the crystal of (IV), the cations and the anions are connected by C—H⋯O, N—H⋯O and C—H⋯F hydrogen bonds and by C—H⋯π inter­actions, forming sheets which in turn inter­act to maintain the crystal structure by linking through the oxygen atoms of water mol­ecules and van der Waals inter­actions, giving the whole structure.