Channappa N. Kavitha

1-[4-(4-Hy-droxy-phen-yl)piperazin-1-yl]ethanone.

In the title compound, C12H16N2O2, the piperazine ring has a chair conformation. The dihedral angle between the mean planes of the benzene ring and the acetyl group is 48.7 (1)°. In the crystal, molecules are linked via O—H⋯O hydrogen bonds, forming chains propagating along [010].

4-[Bis(4-fluoro­phen­yl)meth­yl]-1-[(2E)-3-phenyl­prop-2-en-1-yl]piperazin-1-ium 3-carb­oxy­propano­ate

In the title salt, C26H27F2N2 +·C4H5O4 −, the piperazine N atom bearing the vinylic substituent is protonated. The piperazine ring adopts a chair conformation. In ther crystal, the succinate monoanions are connected via short O—H⋯O hydrogen bonds between the carboxylic acid and carboxylate groups into undulating chains extending along [001] and the flunarizinium monocations are attached to these chains via N+—H⋯O− hydrogen bonds. C—H⋯O interactions connect these chains into a three-dimensional network. The shortest centroid–centroid distance of 3.7256 (10) Å was found between one of the fluorinated benzene rings and the non-fluorinated phenyl ring in the neighbouring molecule related by a glide plane.

[2-(Benzyl­idene­amino)-4,5,6,7-tetra­hydro­benzo[b]thio­phen-3-yl](phen­yl)methanone

In the title compound, C22H19NOS, the cyclohexene ring of the tetrahydrobenzothiophenyl ring system adopts a slightly distorted half-chair conformation and is twisted slightly [7.5 (8)° for the major disorder component] from the mean plane of the thiophene ring. The dihedral angles between the mean planes of the thiophene ring and the phenyl rings are 65.7 (3) and 8.3 (4)°. The phenyl rings are twisted with respect to each other by 73.8 (7)°. Disorder was modeled for four C atoms of the cyclohexene ring over two sets of sites with an occupancy ratio of 0.659 (2):0.341 (2). In the crystal, a single weak C—H⋯O interaction links the molecules into [001] chains.

{2-[(2-Hy-droxy-benzyl-idene)amino]-4,5,6,7-tetra-hydro-1-benzo-thio-phen-3-yl}(phen-yl)methanone.

In the title compound, C22H19NO2S, the cyclohexene ring adopts a slightly distorted half-chair conformation. The dihedral angles between the mean planes of the thiophene ring and the phenyl and 2-hydroxyphenyl rings are 70.4 (5) and 12.1 (9)°, respectively. The phenyl and 2-hydroxyphenyl rings are twisted with respect to one another by 81.0 (6)°. A short intramolecular O—H⋯N hydrogen bond is observed. In the crystal, weak C—H⋯O interactions link the molecules into zigzag chains diagonally along [100] .

Cinnarizinium bis­(p-toluene­sulfonate) dihydrate

The asymmetric unit of the title salt [systematic name: 1-benzhydryl-4-cinnamylpiperazine-1,4-diium bis(p-toluenesulfonate) dihydrate], C26H30N2 2+·2C7H7O3S−·2H2O, consists of a diprotonated cinnarizinium cation hydrogen bonded through two water molecules to two independent p-toluenesulfonate anions, one which is disordered over two sets of sites in a 0.793 (3):0.207 (3) ratio. In the cation, the piperazine ring adopts a chair configuration and contains two positively charged N atoms with quarternery character. The dihedral angle between the two benzene rings in the benzhydryl group is 71.8 (1)°. The benzene ring flanked opposite the piperazine ring is twisted by 75.9 (9) and 8.8 (3)° from these two benzene rings. In the crystal, the [N—H⋯Owater—H⋯O( S)]2 hydrogen-bonded asymmetric unit is connected by further O—H⋯O hydrogen bonds linking the components into chains along [100].

4-Methyl-N-(4-nitro­benzyl­idene)piperazin-1-amine

In the title compound, C12H16N4O2, the piperazine ring is in a slightly distorted chair conformation. In the molecule, the mean plane of the nitro group is twisted by 8.0 (3)° from that of the benzene ring. Also, the mean plane of the 2-nitrobenzyl ring is twisted slightly from that of the piperazine ring, with an N—N=C—C torsion angle of −176.24 (11)°. In the crystal, pairs of weak C—H⋯O interactions link the molecules into dimers approximately along [010].

Flunarizinium hydrogen maleate

In the cation of the title salt {systematic name: 4-[bis(4-fluorophenyl)methyl]-1-[(2E)-3-phenylprop-2-en-1-yl]piperazin-1-ium hydrogen maleate}, C26H27F2N2 +·C4H3O4 −, the protonated piperazine ring is in a chair conformation. The dihedral angle between the 4-fluorophenyl rings is 68.2 (2)°. An intramolecular O—H⋯O hydrogen bond occurs in the anion. In the crystal, N—H⋯O, C—H⋯O and C—H⋯F interactions are observed, which link the ions into [001] chains.

The crystal structures of three clozapinium salts: different mol-ecular configurations, and supra-molecular assembly in one, two and three dimensions.

In three simple clozapinium salts, the unprotonated N atom of the piperazine ring has been variously found to have a pyramidal or planar geometry, with the tricyclic component occupying either the axial or the equatorial position. The supramolecular assembly is one-dimensional in the 3,5-dinitrobenzoate salt, two-dimensional in the hydrogen maleate salt and three-dimensional in the 2-hydroxybenzoate salt.

1-Piperonylpiperazinium 4-nitro-benzoate monohydrate.

In the title hydrated salt [systematic name: 1-(1,3-benzodioxol-5-ylmethyl)piperazin-1-ium 4-nitrobenzoate monohydrate], C12H17N2O2 +·C7H4NO4 −·H2O, the piperazinium ring of the cation adopts a slightly distorted chair conformation. The piperonyl and piperazine rings are rotated with respect to each other with an N—C—C—C torsion angle of 45.6 (2)°. In the anion, the nitro group is almost coplanar with the adjacent benzene ring, forming a dihedral angle of only 3.9 (4)°. In the crystal, the cations, anions and water molecules are linked through N—H⋯O and O—H⋯O hydrogen bonds into chains along the a axis. In addition, weaker intermolecular C—H⋯O interactions are also observed within the chains. The anions form centrosymmetric couples through π-stacking interactions, with an intercentroid distance of 3.681 (4) Å between the benzene rings.

{2-[(4-Nitro­benzyl­idene)amino]-4,5,6,7-tetrahydro-1-benzo­thio­phen-3-yl}(phen­yl)methanone

In the title compound, C22H18N2O3S, disorder is found in the benzoyl group (A and B), as well as for four C atoms of the cyclohexene ring. Two orientations were modeled in a 0.583 (5):0.417 (5) ratio. The cyclohexene ring is in a distorted chair conformation. The dihedral angles between the mean plane of the thiophene ring and the 4-nitrobenzene and phenyl rings are 30.9 (8) and 64.8 (3) (A) and 62.4 (7)° (B). The mean planes of the 4-nitrobenzene and the phenyl rings are almost perpendicular to each other, with dihedral angles of 85.4 (1) (A) and 83.9 (8)° (B). An extensive array of weak C—H⋯O interactions consolidate molecules into a three-dimensional architecture, forming chains along [001] and [010] and layers parallel to (011).