Crystal structure and Hirshfeld surface analysis of (E)-4-chloro-N-{2-[2-(4-nitrobenzylidene)hydrazin-1-yl]-2-oxoethyl}benzenesulfonamide N,N-dimethylformamide monosolvate

Reaction of N-(4-chlorobenzenesulfonyl)glycinyl hydrazide with 4-nitrobenzaldehyde gives the N,N-dimethylformamide monosolvated N-acylhydrazone derivative, (E)-N-{2-[2-(4-nitrobenzylidene)- hydrazine-1-yl]-2-oxoethyl}-4-χhlorobenzenesulfonamide. Rings of (10) and (11) graph-set motifs are formed in the crystal structure by N—H⋯O and C—H⋯O hydrogen bonds. The two-dimensional fingerprint (FP) plots for significant intermolecular interactions indicate that the greatest contribution is from the O⋯H/H⋯O contacts (31.3%), corresponding to N⋯H⋯O/C⋯H⋯O interactions.

The asymmetric unit of the title compound, C 15 H 13 ClN 4 O 5 SÁC 3 H 7 NO, contains one molecule each of the Schiff base and the solvent dimethylformamide. The hydrazone group adopts an E configuration about the C N bond. The dihedral angle between the two aromatic rings is 86.58 (2) . In the crystal, pairs of N-HÁ Á ÁO hydrogen bonds between centrosymmetrically related molecules generates rings with an R 2 2 (10) graph-set motif. The dimers are further linked via N-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds, leading to the formation of R 3 3 (11) ring motifs. C-HÁ Á Á interactions are also observed. The intermolecular interactions in the crystal structure were quantified and analysed using Hirshfeld surface analysis, which indicates that the most significant contacts in packing are OÁ Á ÁH/HÁ Á ÁO (31.3%), followed by HÁ Á ÁH (25.4%) and CÁ Á ÁH/HÁ Á ÁC (13.0%).

Chemical context
Supramolecular chemistry is based upon non-covalent interactions such as hydrogen bonding,stacking and van der Waals interactions (Beatty et al., 2003;Biradha et al., 2003;Aakerö y & Beatty, 2001). The presence of strong hydrogenbond donors and acceptors on the molecular periphery results in cross-linking of molecules via strong hydrogen bonds into dimers, rings, chains and other hydrogen-bonded motifs. The acidity of the C-H donor group determines the strength of C-HÁ Á ÁO interactions (Purandara et al., 2017a,b). The study of C-HÁ Á ÁO interactions in compounds containing chlorine atoms suggests that the more acidic the C-H hydrogen involved in a C-HÁ Á ÁO interaction, the stronger is the interaction (Desiraju et al., 1991). The presence of donors and acceptors make N-acylhydrazones important candidates for structural studies in this field. An attractive feature of hydrazones is their ability to form geometrical E/Z isomers because of the presence of the C N double bond (Palla et al., 1986) and conformational isomers because of a partly hindered rotation around the amide C-N bond. The nature and site of the substituents in the hydrazone moiety and hydrogen-bonding interactions decide the stereochemistry. In a continuation of our efforts to explore the effect of substituents on the structures of N-acylhydrazone derivatives, we report herein the synthesis, crystal structure and Hirshfeld analysis of the title compound, (E)-4-chloro-N-{2-[2-(4-nitro-benzylidene)hydrazin-1-yl]-2-oxoethyl}benzenesulfonamide N,N-dimethylformamide monosolvate.

Figure 2
The hydrogen-bonding pattern (dashed lines) in the title compound.

Figure 3
The molecular packing of the title compound, with hydrogen bonding shown as dashed lines.
dimers. The dimers are then linked via N-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds, leading to the formation of R 3 3 (11) ring motifs. These rings are further extended by two C-HÁ Á ÁO hydrogen bonds, one involving a methyl hydrogen atom of the solvent molecule (H18B) and the sulfonyl oxygen atom (O2) forming C 3 3 (18) chains along the c axis, and the other involving an aromatic C-H (H14) and the nitro O4 atom, giving rise to inversion dimers with an R 2 2 (10) graph-set motif (Fig. 3). In addition, the hydrazone molecule is involved in C-HÁ Á Á interactions (Fig. 4, Table 1). The hydrogenbonding pattern in the title compound is similar to that

Hirshfield Surface analysis
CrystalExplorer3.1 (Wolff et al., 2012) was used to generate the molecular Hirshfeld surfaces (d norm , electrostatic potential and curvedness) to analyse the close contacts in the title compound. The electrostatic potentials were calculated using TONTO (Spackman et al., 2008;Jayatilaka et al., 2005) integrated within CrystalExplorer. The molecular Hirshfeld surfaces were generated using a standard (high) surface resolution with the 3D d norm surfaces mapped over a fixed colour scale of À0.5849 to 1.3948. The curvedness was mapped in the colour range of À4.0 to 0.4. The electrostatic potentials were mapped on Hirshfeld surfaces using the STO-3G basis set at the Hartree-Fock level theory over a range AE0.1au. The C-HÁ Á Á interactions (green dotted lines) observed in the structure of the title compound.

Figure 5
View of the Hirshfeld surface mapped over d norm .

Figure 6
View of the Hirshfeld surface mapped over the electrostatic potential.
In the Hirshfeld surfaces mapped over d norm (Fig. 5), the strong N-HÁ Á ÁO interactions can be observed as bright-red spots between oxygen (O) and hydrogen (H) atoms. These interactions are further confirmed by Hirshfeld surfaces mapped over the electrostatic potential (Fig. 6), showing the negative potential around the oxygen atoms as light-red clouds and the positive potential around hydrogen atoms as light-blue clouds. The two-dimensional fingerprint (FP) plots for significant intermolecular interactions are illustrated in Fig. 7. The greatest contribution from the OÁ Á ÁH/HÁ Á ÁO contacts is 31.3%, corresponding to N-HÁ Á ÁO/C-HÁ Á ÁO interactions, is represented by a pair of sharp spikes characteristic of a strong hydrogen-bonding interaction having d e + d i values of about 1.8 and 2.0 Å (Fig. 7b). The HÁ Á ÁH interactions appear as the largest region of the fingerprint plot with a high concentration in the middle region, shown in light blue, at d e = d i $1.4 Å (Fig. 7a) with an overall contribution to the Hirshfeld surfaces of 25.4%. The CÁ Á ÁH contacts, which refer to C-HÁ Á Á interactions, contribute 13.0% of the Hirshfeld surfaces. The presence of C-HÁ Á Á interactions is indicated by the appearance of two broad spikes having almost same d e + d i 3.1 Å . The CÁ Á ÁC contacts contribute 4.5% of the Hirshfeld surfaces, featuring two successive triangles with a minimum (d e + d i ) distance of $3.5 Å , which is greater than van der Waals separation, confirming the absence ofstacking interactions. This is also evident from the absence of flat regions in the Hirshfeld surface mapped over curvedness (Fig. 8).   View of the Hirshfeld surface mapped over curvedness.

Synthesis and crystallization
4-Chlorobenzenesulfonyl chloride (0.01 mol) was added to glycine (0.02 mol) dissolved in an aqueous solution of potassium carbonate (0.06 mol, 50 ml). The reaction mixture was stirred at 373 K for 6 h, left overnight at room temperature, then filtered and treated with dilute hydrochloric acid. The solid N-(4-chlorobenzenesulfonyl)glycine (L1) obtained was crystallized from aqueous ethanol. Sulfuric acid (0.5 ml) was added to L1 (0.02 mol) dissolved in ethanol (30 ml) and the mixture was refluxed. The reaction mixture was monitored by TLC at regular intervals. After completion of the reaction, the reaction mixture was concentrated to remove the excess ethanol. The product, N-(4-chlorobenzenesulfonyl)glycine ethyl ester (L2) obtained was poured into water, neutralized with sodium bicarbonate and recrystallized from acetone. The pure L2 (0.01 mol) was then added in small portions to a stirred solution of 99% hydrazine hydrate (10 ml) in 30 ml ethanol and the mixture was refluxed for 6 h. After cooling to room temperature, the resulting precipitate was filtered, washed with cold water and dried to obtain N-(4-chlorobenzenesulfonyl)glycinyl hydrazide (L3). A mixture of L3 (0.01 mol) and 4-nitrobenzaldehyde (0.01 mol) in anhydrous methanol (30 ml) and two drops of glacial acetic acid was refluxed for 8h. After cooling, the precipitate was collected by vacuum filtration, washed with cold methanol and dried. It was recrystallized to a constant melting point from methanol (493-496 K).
The purity of the compound was checked by TLC and characterized by its IR spectrum.  26, 44.42, 123.94, 127.85, 128.53, 129.19, 137.23, 139.77, 141.47, 144.68, 147.75, 164.52, 169.34. Plate-like yellow single crystals of the title compound suitable for X-ray analysis were grown from its DMF solution by slow evaporation of the solvent.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2. H atoms bonded to C atoms were positioned with idealized geometry, C-H = 0.93 (aromatic), 0.96 (methyl) or 0.97 Å (methylene) and refined using a riding model with isotropic displacement parameters set at 1.2U eq (C, N) or 1.5U eq (C) for methyl H atoms.. The amino H atoms were freely refined with the N-H distances restrained to 0.86 (2) Å .    (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: Mercury (Macrae et al., 2008) and PLATON (Spek, 2015); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015).  Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.