Dichlorido{N′-[(pyridin-2-yl)methylidene-κN]acetohydrazide-κ2 N′,O}copper(II)

In the title compound, [CuCl2(C8H9N3O)], the CuII atom has a distorted square-pyramidal CuCl2N2O coordination geometry. The tridentate acetohydrazide ligand occupies three basal positions, the fourth basal position being defined by a chloride anion at a distance of 2.2116 (6) Å. The second chloride anion is in the apical position and forms a longer Cu—Cl distance of 2.4655 (7) Å. Intermolecular N—H⋯Cl hydrogen bonds are present in the crystal, leading to the formation of chains along [10].

In the title compound, [CuCl 2 (C 8 H 9 N 3 O)], the Cu II atom has a distorted square-pyramidal CuCl 2 N 2 O coordination geometry. The tridentate acetohydrazide ligand occupies three basal positions, the fourth basal position being defined by a chloride anion at a distance of 2.2116 (6) Å . The second chloride anion is in the apical position and forms a longer Cu-Cl distance of 2.4655 (7) Å . Intermolecular N-HÁ Á ÁCl hydrogen bonds are present in the crystal, leading to the formation of chains along [101].
We are grateful to the National Science Council of Taiwan for financial support.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: WM2553). The structure of a copper(II) dichloride complex with a similar tridentate hydrazone ligand has been reported in the literature (Datta, et al., 2011).

Experimental
The tridentate acetohydrazide ligand precursor was prepared according to the literature procedure (Ray et al., 2008b). To a hot methanolic solution (20 ml) of anhydrous CuCl 2 (0.134 g, 1.0 mmol), the ligand (0.163 g, 1.0 mmol) was added, which produced immediately an intensely green solution. The mixture was then heated to boiling. On cooling to room temperature and after slow evaporation of the green solution, dark green rectangular shaped single crystals of the complex were separated out after 3 days. The crystals were filtered off and washed with water and dried in air.

Refinement
Carbon-and nitrogen-bound H-atoms were placed in calculated positions (C-H 0.95 to 0.98 Å and N-H 0.88 Å) and were included in the refinement in the riding model approximation, with U iso (H) set to 1.2 and 1.5 times U eq (C,N).   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 > σ(F 2 ) is used only for calculating Rfactors(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.