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 \overline{1} 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.