Di-μ-thiocyanato-bis({2,4-dichloro-6-[2-(diethylamino)ethyliminomethyl]phenolato}copper(II))

The title compound, [Cu2(NCS)2(C13H17Cl2N2O)2], was obtained by the reaction of 3,5-dichlorosalicylaldehyde, N,N-diethylethane-1,2-diamine, sodium thiocyanate, and copper(II) acetate in an ethanol solution. It crystallizes as a centrosymmetric dimer with a very long Cu⋯S axial bond [2.972 (3) Å]. The Cu atom is five-coordinated by the three donor atoms of the Schiff base ligand, 2,4-dichloro-6-[(2-diethylaminoethylimino)methyl]phenol, one N atom of a thiocyanate group, and one S atom of a symmetry-related thiocyanate group, forming a slightly distorted square-pyramidal geometry.


S1. Comment
Schiff base compounds have been reported to have excellent biological activity (Shi et al., 2007;Panneerselvam et al., 2005). Metal complexes derived from the Schiff bases have also been shown to have excellent biological activity (Singh et al., 2006(Singh et al., , 2007Zhong et al., 2006). As part of our investigations of the structures of metal complexes derived from Schiff bases, we report herein the crystal structure of the title copper complex, (I).
Compound (I) is a centrosymmetric dinuclear copper(II) complex (Fig. 1). The Cu atom is five-coordinated by the three donor atoms (O1, N1 and N2) of the Schiff base ligand 2,4-dichloro-6-[(2-diethylaminoethylimino)methyl]phenol, one N atom of a thiocyanate group, and one S atom of the centrosymmetrically related thiocyanate group, so forming a slightly distorted square-pyramidal geometry. The Cu atom is displaced out of the best least-squares plane defined by the four basal donor atoms by 0.123 (2) Å. Apart from the long Cu···S axial bond [2.972 (3) Å], the other coordination bond distances and angles are within normal ranges (Allen et al., 1987).

S2. Experimental
The title compound was obtained by the reaction of equimolar amounts of 3,5-dichlorosalicylaldehyde, N,N-diethylethane-1,2-diamine, sodium thiocyanate, and copper acetate in an ethanol solution. Blue block-like single crystals were obtained by slow evaporation of the filtrate in air.

S3. Refinement
H atoms were positioned geometrically and treated as riding atoms, with C-H = 0.93-0.97Å and U iso (H) = 1.2 (1.5 for methyl groups) times U eq (C).  The molecular structure of complex (I), with atom labels and 30% probability displacement ellipsoids for non-H atoms.

Di-µ-thiocyanato-bis({2,4-dichloro-6-[2-(diethylamino)ethyliminomethyl]phenolato}copper(II))
Crystal data 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 R-factors(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.

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