Crystal structure of bis[μ-S-hexyl 3-(2-oxidobenzylidene)dithiocarbazato-κ4 O,N 3,S:O]dicopper(II)

The title compound, [Cu2(C14H18N2OS2)2], is a binuclear copper(II) complex of an oxybenzylidenedithiocarbazate ligand. The ligand coordinates in a tridentate manner through N-, S- and O-donor atoms. Each O atom also bridges to a second CuII ion to form the binuclear species. It has a central Cu2O2 rhomboid moiety and a metal-to-metal separation of 2.9923 (6) Å. In the crystal, the binuclear complexes stack along the a axis with all the hexyl chains located side-by-side, forming a hydrophobic region. The complexes are linked via C—H⋯N hydrogen bonds, forming chains along the c-axis direction. One CuII atom has the S atom of a symmetry-related complex located approximately in the apical position at 2.9740 (11) Å. This weak interaction links the chains to form slabs parallel to the ac plane.


Related literature
. In square planar metal complexes reported so far dithiocarbazato ligands coordinate in a bidentate manner through the N,S donors leading to bischelated species with a trans (Howlader et al., 2015) or cis (Begum et al., 2015) configuration. The presence of an oxobenzylidene moiety is expected to induce the ligand to coordinate to the metal through the N,S,O donors. Continuing our studies on S-containing Schiff bases (Howlader et al., 2015;Begum et al., 2015), we report herein on the crystal structure of an unexpected binuclear copper(II) complex of the ligand S-hexyl-β-N-(2-hydroxybenzylidene)dithiocarbazate.
In the title compound, Fig. 1, the presence of the oxobenzylidene moiety in the Schiff base ligand has induced it to coordinate to the metal through the N, S, and O donor atoms, with formation of five-and six-membered chelate rings.
supporting information

S2. Synthesis and crystallization
A solution of Cu(CH 3 COO) 2 .H 2 O (0.11 g, 0.5 mmol, 15 ml methanol) was added to a solution of the S-hexyl-β-N-(2-hydroxybenzylidene)dithiocarbazate (1.0 mmol, 10 ml methanol). The resulting mixture was stirred at room temperature for 5 h. A dark reddish brown precipitate was formed, filtered off, washed with methanol and dried in vacuo over anhydrous CaCl 2 . Dark reddish brown single crystals suitable for X-ray diffraction were obtained by slow evaporation from a mixture of dichloromethane and acetonitrile (3:1); m.p. 443 K.

S3. Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2. All H atoms were fixed geometrically (C-H = 0.95 -0.99 Å) and refined as riding with U iso (H) = 1.2U eq (C).

Figure 1
A view of the molecular structure of the title complex, with atom labelling. The displacement ellipsoids are drawn at the 50% probability level.