Bis{1-[(E)-(2-chlorophenyl)diazenyl]naphthalen-2-olato}copper(II)

The CuII atom in the title compound, [Cu(C16H10ClN2O)2], is located on an inversion center and is tetracoordinated by two N and two O atoms from two bidentate 1-[(E)-(2-chlorophenyl)diazenyl]naphthalen-2-olate ligands, forming a square-planar complex. In the crystal, molecules are linked via weak C—H⋯O and C—H⋯Cl hydrogen bonds, forming chains propagating along [010]. There are also π–π interactions present involving adjacent naphthalene rings [centroid–centroid distance = 3.661 (13) Å].

The title Cu II complex ( Fig. 1) contains two six-membered rings coordinated from two N,O-bidentate phenylazonaphtholate ligands. It was found that the asymmetric unit contains one half molecule, the Cu atom lying on a centre of inversion. The Cu atom is tetra-coordinated with a normal square planar environment in which two N atoms and two O atoms are coplanar. The two N atoms and two O atoms around Cu atom are trans to each other with an O1-Cu1-N2 bond angle of 87.48 (8)° and O1-Cu1-N2 i angle of 92.52 (8)°; symmetry code: (i) (i) -x+2, -y, -z+1. The Cu1-O1 and Cu1-N2 bond distances are 1.8975 (17) Å and 1.961 (2) Å, respectively. The Cu1···Cl1 distances are 3.1525 (7) Å.

Refinement
The C-bound H atoms were included in calculated positions and treated as riding atoms: C-H = 0.93 Å with U iso (H) = 1.2U eq (C). Despite a µ value = 1.08 mm -1 an absorption correction was not applied in view of the very small size of the crystal [0.01 × 0.01 × 0.01 mm].

Figure 1
View of the molecular structure of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 50% probability level [symmetry code: (i) -x+2, -y, -z+1]

Figure 2
Partial view along the b axis of the crystal packing of the title compound, showing the hydrogen bonds as dashed lines (see Table 1 for details).  where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.48 e Å −3 Δρ min = −0.28 e Å −3 Special details Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles Refinement. Refinement on F 2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses 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 observed criterion of F 2 > σ(F 2 ) is used only for calculating -R-factor-obs 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.

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