Crystal structures of 4-phenyl-piperazin-1-ium 6-chloro-5-ethyl-2,4-dioxopyrimidin-1-ide and 4-phenyl-piperazin-1-ium 6-chloro-5-isopropyl-2,4-dioxopyrimidin-1-ide

The structures of eleven (4-phen-yl)piperazinium salts containing organic anions

Eleven (4-phen-yl)piperazinium salts containing organic anions have been prepared and structurally characterized, namely, 4-phenyl-piperazin-1-ium 4-fluoro-benzoate monohydrate, C10H15N2 +·C7H4FO2 -·H2O, 1; 4-phenyl-piperazin-1-ium 4-bromo-benzoate monohydrate, C10H15N2 +·C7H4BrO2 -·H2O, 3; 4-phenyl-piperazin-1-ium 4-iodo-benzoate, C10H15N2 +·C7H4IO2 -, 4; 4-phenyl-piperazin-1-ium 4-nitro-benzoate, C10H15N2 +·C7H4NO4 -, 5; 4-phenyl-piperazin-1-ium 3,5-di-nitro-salicylate, C10H15N2 +·C7H3N2O7 -, 6; 4-phenyl-piperazin-1-ium 3,5-di-nitro-benzoate, C10H15N2 +·C7H3N2O6 -, 7; 4-phenyl-piperazin-1-ium picrate, C10H15N2 +·C6H2N3O7 -, 8; 4-phenyl-piperazin-1-ium benzoate monohydrate, C10H15N2 +·C7H5O2 -·H2O, 9; 4-phenyl-piperazin-1-ium p-toluene-sulfonate, C10H15N2 +·C7H7O3S-, 10; 4-phenyl-piperazin-1-ium tartarate monohydrate, C10H15N2 +·C4H5O6 -·H2O, 11; and 4-phenyl-piperazin-1-ium fumarate, C10H15N2 +·C4H3O4 -, 12. Compounds 1 and 3-12 are all 1:1 salts with the acid proton transferred to the phenyl-piperaizine basic N atom (the secondary amine) with the exception of 3 where there is disorder in the proton position with it being 68% attached to the base and 32% attached to the acid. Of the structures with similar stoichiometries only 3 and 9 are isomorphous. The 4-phenyl substituent in all cases occupies an equatorial position except for 12 where it is in an axial position. The crystal chosen for structure 7 was refined as a non-merohedral twin. There is disorder in 5, 6, 10 and 11. For both 5 and 6, a nitro group is disordered and was modeled with two equivalent orientations with occupancies of 0.62 (3)/0.38 (3) and 0.690 (11)/0.310 (11), respectively. For 6, 10 and 11, this disorder is associated with the phenyl ring of the phenyl-piperazinium cation with occupancies of 0.687 (10)/0.313 (10), 0.51 (7)/0.49 (7) and 0.611 (13)/389 (13), respectively. For all salts, the packing is dominated by the N-H⋯O hydrogen bonds formed by the cation and anion. In addition, several structures contain C-H⋯π (1, 3, 4, 8, 9, 10, and 12) and aromatic π-π stacking inter-actions (6 and 8) and one structure (5) contains a -NO2⋯π inter-action. For all structures, the Hirshfeld surface fingerprint plots show the expected prominent spikes as a result of the N-H⋯O and O-H⋯O hydrogen bonds.

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

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.