Synthesis and crystal structures of (E)-N′-(4-chloro-3-nitrobenzylidene)acetohydrazide and (E)-2-(4-chlorobenzylidene)-1-(quinolin-8-yl)hydrazine

Two benzylidenehydrazinederivatives have been synthesized and structurally characterized.


Structural commentary
The crystal structure of IV is monoclinic, P2 1 /c. The asymmetric unit of the crystal structure consists of a single molecule [ Fig. 1(a)]. Apart from the nitro group and the H atoms of the    methyl group, the molecule of IV is planar, with a maximum deviation of 0.11 Å for atom Cl1 from the least-squares plane through all the atoms. The nitro group shows positional disorder in the crystal structure (details are available in the Refinement section). The nitro group deviates from the plane through the rest of the molecule by a twist around the C1-N1 bond of 49.3 (1) for the major component and 57.1 (5) for the minor component. The molecular planarity and twist of the nitro group are consistent with the conformation reported for other structures containing the [(4-chloro-3-nitrophenyl)methylidene]formohydrazide moiety (Gu et al., 2012;Mokhnache & Bourzami, 2020).

Supramolecular features
In the crystal structure of IV, neighbouring pairs of molecules, related by inversion symmetry, are linked by two intermolecular (N3-H3AÁ Á ÁO3) hydrogen bonds [ Table 1 and Fig. 1(b)]. The two hydrogen bonds form rings with R 2 2 (8) geometry (Etter et al., 1990;Bernstein et al., 1995) between the molecules. The linked molecular pairs form columns along the a axis of the crystal [ Fig. 1(c)] guided by C-halogenÁ Á Á interactions (Prasanna & Guru Row, 2000;Mitra et al., 2020), with ClÁ Á Áring-centroid distances of 3.51 Å . Within a stack, the planes of the molecules are parallel and close to either the (124) or (124) plane. C-HÁ Á ÁO contacts are also observed in the structure, as shown in Table 1 and Fig. 1(b).
The molecules of compound VII are arranged in a herringbone pattern in the crystal [ Fig. 2(b)]. Molecules of the same type (i.e. molecule 1 or 2) are linked through C-HÁ Á ÁCl contacts (Table 2) Table 2 Hydrogen-bond geometry (Å , ) for VII.
For both structures: Z = 4. Experiments were carried out with Cu K radiation using a Rigaku OD SuperNova Dual source diffractometer with an Atlas detector. The absorption corrections were Gaussian (CrysAlis PRO; Rigaku OD, 2022

Refinement
Crystal and structure refinement data are shown in Table 3. The nitro group in IV is disordered, with the two components related by a 75.0 (6) (Farrugia, 2012); software used to prepare material for publication: Mercury (Macrae et al., 2020).

(E)-N′-(4-Chloro-3-nitrobenzylidene)acetohydrazide (IV)
Crystal data 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. Refinement. Single-crystal XRD data were collected on an Agilent SuperNova Dual Atlas diffractometer with a mirror monochromator using Cu radiation. Crystal structures were solved and refined using SHELXT (Sheldrick, 2015a) and SHELXL (Sheldrick, 2015b). Non-hydrogen atoms for both IV and VII were refined with anisotropic displacement parameters.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Occ. (

(E)-2-(4-Chlorobenzylidene)-1-(quinolin-8-yl)hydrazine (VII)
Crystal data 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. Refinement. Single-crystal XRD data were collected on an Agilent SuperNova Dual Atlas diffractometer with a mirror monochromator using Cu radiation. Crystal structures were solved and refined using SHELXT (Sheldrick, 2015a) and SHELXL (Sheldrick, 2015b). Non-hydrogen atoms for both IV and VII were refined with anisotropic displacement parameters.
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )