An unknown solvate of 1-(2,4-dichlorobenzyl)-4-[(4-methylphenyl)sulfonyl]piperazine

In the title compound, C18H20Cl2N2O2S, the piperazine ring adopts a chair conformation. The dihedral angle between the sulfonyl-bound benzene ring and the best-fit plane through the six non-H atoms of the piperazine ring is 72.22 (12)°; those between the dichlorobenzene ring and the sulfonyl and piperazine rings are 2.44 (13) and 74.16 (2)°, respectively. In the crystal, molecules are connected through weak C—H⋯O interactions into a hexameric unit generating a R 6 6(60) motif in the ab plane. The molecules are also connected into C(4) chains through weak C—H⋯N interactions. The solvent used to grow the crystal was a mixture of dichloromethane and methanol, but the resulting electron density was uninterpretable. The solvent contribution to the scattering was removed with the SQUEEZE routine in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148–155]. The formula mass and unit-cell characteristics do not take into account the disordered solvent.

In the title compound, C 18 H 20 Cl 2 N 2 O 2 S, the piperazine ring adopts a chair conformation. The dihedral angle between the sulfonyl-bound benzene ring and the best-fit plane through the six non-H atoms of the piperazine ring is 72.22 (12) ; those between the dichlorobenzene ring and the sulfonyl and piperazine rings are 2.44 (13) and 74.16 (2) , respectively. In the crystal, molecules are connected through weak C-HÁ Á ÁO interactions into a hexameric unit generating a R 6 6 (60) motif in the ab plane. The molecules are also connected into C(4) chains through weak C-HÁ Á ÁN interactions. The solvent used to grow the crystal was a mixture of dichloromethane and methanol, but the resulting electron density was uninterpretable. The solvent contribution to the scattering was removed with the SQUEEZE routine in PLATON [Spek (2009). Acta Cryst. D65,[148][149][150][151][152][153][154][155]. The formula mass and unitcell characteristics do not take into account the disordered solvent.   Table 1 Hydrogen-bond geometry (Å , ).

Comment
As a part of our continued efforts to study the crystal structures of N-(aryl)(4-tosylpiperazin-1-yl)methanone derivatives (Sreenivasa et al., 2013a,b), we report herein the crystal structure of the title compound.
In the title compound, Fig. 1, the piperazine ring adopts a chair conformation. The dihedral angle between the sulfonylbound benzene ring and the best fit plane through the six non-H atoms of the piperazine ring is 72.22 (12)°, while those between the dichlorobenzene and sulfonyl rings and the dichlorobenzene and piperazine rings are 2.44 (13) and 74.16 (2)° respectively. In the crystal, molecules are connected through weak C18-H18···O2 interactions into a hexameric unit generating a R 6 6 (60) motif, Fig. 2 and Table 1. The molecules are also connected into C(4) chains through a weak C17-H17···N2 interaction, Fig. 3 and Table 1.

Experimental
A mixture of 1-tosylpiperazine (0.01 mmol), potassium carbonate (0.03 mmol) and 2,4-dichlorobenzyl bromide (0.01 mmol) was added into dry acetonitrile (5 ml). The mixture was stirred at 85°C for 8 h. The reaction was monitored by TLC. Solvent was removed by vacuum distillation and the crude product obtained was purified by column chromatography using 230-400 silica gel and petroleum ether/ethyl acetate as eluent. Colourless prisms were obtained from a mixture of dichloromethane/methanol (7:3) by slow evaporation.

Refinement
All H atoms were included in calculated positions with C-H bond distances 0.93-0.97 Å and refined in a riding model approximation with U iso (H) = 1.2-1.5U eq (C). The solvent used to grow the crystal was a mixture of dichloromethane and methanol. But the resulting electron density was largely uninterpretable. It was decided to model it with the SQUEEZE routine in PLATON (Spek, 2009); more details are given in "_platon_squeeze_details".    Molecular packing in the title compound displaying C(4) chains. Special details Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.