Crystal structure of bis{μ-4-methyl-N′-[3-(oxidoimino)butan-2-ylidene]benzenesulfonohydrazidato}bis[(dimethyl sulfoxide-κO)copper(II)]

In the title compound, [Cu2(C11H13N3O3S)2(C2H6OS)2], the CuII cation is N,N′,O-chelated by a deprotonated hydroxyimino-tosylhydrazone ligand and coordinated by a dimethyl sulfoxide molecule. One O atom from the adjacent hydroxyimino-tosylhydrazone ligand bridges the CuII cation, forming the centrosymmetric dimeric complex. The cation is in an overall distorted N2O3 square-pyramidal coordination environment. The methylbenzene ring is twisted with respect to the hydrazine fragment, with a dihedral angle of 89.54 (9)° between the planes. An intramolecular C—H⋯O hydrogen bond occurs. In the crystal, molecules are linked by weak C—H⋯O and C—H⋯S interactions. Weak π–π stacking is also observed between parallel benzene rings of adjacent molecules, the centroid–centroid distance being 3.9592 (17) Å.


S2. Structural commentary
Hydroxyimino-tosylhydrazone derivatives are N,O-donors that show an application as complexing agents (Beger et al., 1991). In the crystal structure of the title compound the Cu II cations are five-coordinated by one crystallographically independent deprotonated hydroxyimino-tosylhydrazone derivative, one DMSO molecule and one O-atom from a second, symmetry generated, hydroxyimino-tosylhydrazone derivative into dimers (Fig. 1).

S5. Synthesis and crystallization
Starting materials were commercially available and were used without further purification. The ligand synthesis was adapted from a procedure reported previously and its structure is already published (Bulhosa et al., 2012). N′-[3-(Hydroxyimino)butan-2-ylidene]-4-methylbenzene-1-sulfonohydrazide was dissolved in methanol (2 mmol/40 mL) with stirring maintained for 30 min and deprotonated with sodium, while the solution turns yellow. At the same time, a solution of copper(II) acetate monohydrate (1 mmol/40 mL) in methanol was prepared under continuous stirring. A mixture of both solutions was maintained with stirring at room temperature for 6 h. The methanol was removed by evaporation and crystals suitable for X-ray diffraction were obtained in DMSO by the slow evaporation of the solvent.

S6. Refinement
H atoms attached to C atoms were positioned with idealized geometry and were refined isotropically with U iso (H) set to 1.2 times U eq (C) for the aromatic and 1.5 times U eq (C) for methyl H atoms using a riding model with C-H = 0.93 Å and C-H = 0.96 Å, respectively.

Figure 1
The molecular structure of the title compound with labeling and displacement ellipsoids drawn at the 40% probability level showing the dimeric structure. Symmetry code: (i)-x + 1,-y + 1,-z + 1

Figure 2
Molecules of the title compound arranged along b-axis showing the column of the aromatic rings with very weak π-π interactions.

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. 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.