{N′-[(E)-1-(5-Chloro-2-oxidophenyl)ethylidene]-4-methoxybenzohydrazidato-κ3 O,N′,O′}(1H-imidazole-κN 3)nickel(II)

The title complex displays a slightly distorted square-planar coordination geometry. The crystal features 41-helical chains stabilized by N—H⋯O hydrogen bonding.

In the title complex, [Ni(C 16 H 13 ClN 2 O 3 )(C 3 H 4 N 2 )], the Ni II ion is coordinated by two O atoms and one N atom derived from the dianionic N 0 -[(1E)-1-(5chloro-2-hydroxyphenyl)ethylidene]-4-methoxybenzohydrazide ligand and one N atom from the imidazole molecule. The N 2 O 2 donor set defines an approximate square-planar geometry. The dihedral angles between the imidazole ring and the fused six-membered and methoxybenzene rings are 17.78 (14) and 13.23 (16) , respectively; the dihedral angle between the C 6 rings is 6.63 (12) . The most prominent feature of the molecular packing is the formation of 4 1 -helical chains (along the c axis) mediated by imidazole-N-HÁ Á ÁO(phenoxide) hydrogen bonding; these are linked by methyl-C-HÁ Á ÁCl interactions.

Structure description
Acylhydrazones, as a special kind of Schiff base, have been widely investigated because of their strong coordination ability (Singh et al., 1982;Salem, 1998;Yu et al., 2010) and flexible coordination modes involving the N and O donor atoms (Liu et al., 2005;Chang, 2011;Zheng et al., 2011). As has been widely reported in the literature, acylhydrazone complexes display various biological activities such as anti-microbial (Yang et al., 2020), anti-tubercular (Peng, 2011), anti-cancer (Morgan et al., 2003) and anti-oxidant (Chang et al., 2015). As an extension of work into the structural characterization of aroylhydrazone complexes, the title complex, [Ni(C 16 H 13 ClN 2 O 3 )(C 3 H 4 N 2 )], has been synthesized and its crystal structure determined.
The Ni II ion in the title compound is coordinated by two O atoms and one N atom from the dianionic N 0 -[(1E)-1-(5-chloro-2-hydroxyphenyl)ethylidene]-4-methoxybenzohydra-data reports zide ligand and one N atom from the imidazole molecule. In this complex, the Ni atom is located in a slightly distorted square-planar environment ( Fig. 1 and Table 1). The Ni-O bond lengths are systematically shorter than the Ni-N bonds, and the maximum deviation from the ideal square-planar geometry in terms of angles is found for O1-Ni1-N2 = 82.18 (7) . The two benzene rings, C1-C6 (A) and C10-C15 (B), and the imidazole ring (C) make dihedral angles of 6.63 (12) (A/B), 17.78 (14) (A/C) and 13.23 (16) (B/C).
The molecular packing is consolidated by imidazole-N-HÁ Á ÁO(phenoxide) hydrogen bonding (Table 2) along the c axis, which leads to a 4 1 helical chain. The chains are connected by C-HÁ Á ÁCl interactions (Table 2) into a threedimensional architecture; a view of the unit-cell contents is given in Fig. 2.

Figure 1
The molecular structure, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

data-1
IUCrData ( where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.79 e Å −3 Δρ min = −0.20 e Å −3 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.