Crystal-structure studies of 4-phenyl-piperazin-1-ium 4-eth-oxy-benzoate monohydrate, 4-phenyl-piperazin-1-ium 4-meth-oxy-benzoate monohydrate, 4-phenyl-piperazin-1-ium 4-methyl-benzoate monohydrate and 4-phenyl-piperazin-1-ium tri-fluoro-acetate 0.12-hydrate

Abstract

In this study, four new piperazinium salts, namely, 4-phenyl-piperazin-1-ium 4-eth-oxy-benzoate monohydrate, C₉H₉O₃·C₁₀H₁₅N₂·H₂O (I); 4-phenyl-piperazin-1-ium 4-meth-oxy-benzoate monohydrate, C₁₀H₁₅N₂·C₈H₇O₃·H₂O (II); 4-phenyl-piperazin-1-ium 4-methyl-benzoate monohydrate, C₁₀H₁₅N₂·C₈H₇O₂·H₂O (III); and 4-phenyl-piperazin-1-ium tri-fluoro-acetate 0.12 hydrate, C₁₀H₁₅N₂·C₂F₃O₂·0.12H₂O (IV), have been synthesized. The single-crystal structures of these compounds reveal that all of them crystallize in the triclinic P 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 inter-actions 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 inter-actions, forming sheets which in turn inter-act to maintain the crystal structure by linking through the oxygen atoms of water mol-ecules and van der Waals inter-actions, giving the whole structure.

Keywords: biological activity; crystal structure; hydrogen bonding; piperazine.