Bis(2,S-dimethyldithiocarbazate-κ2 N 3,S)(nitrato-κO)copper(II) nitrate

The title complex, [Cu(NO3)(C3H8N2S2)2]NO3, represents a low-symmetry polymorph (P-1, Z = 4) of a previously reported form [P-1, Z = 2; Ali et al. (2011 ▶). Polyhedron, 30, 542–548]. The CuII atom in each independent cation is found within a distorted square-pyramidal N2S2O coordination geometry defined by two N,S-bidentate ligands and an O atom derived from a monodentate nitrate. The primary difference between the cations is found in the relative orientations of the coordinated nitrate groups, which are directed to opposite sides of the molecule. Supramolecular layers along [110] and sustained by N—H⋯O interactions feature in the crystal packing. These are connected along the c axis by C—H⋯O interactions.

The title complex, [Cu(NO 3 )(C 3 H 8 N 2 S 2 ) 2 ]NO 3 , represents a low-symmetry polymorph (P1, Z = 4) of a previously reported form [P1, Z = 2; Ali et al. (2011). Polyhedron, 30, 542-548]. The Cu II atom in each independent cation is found within a distorted square-pyramidal N 2 S 2 O coordination geometry defined by two N,S-bidentate ligands and an O atom derived from a monodentate nitrate. The primary difference between the cations is found in the relative orientations of the coordinated nitrate groups, which are directed to opposite sides of the molecule. Supramolecular layers along [110] and sustained by N-HÁ Á ÁO interactions feature in the crystal packing. These are connected along the c axis by C-HÁ Á ÁO interactions.
The Cu II atom is coordinated by a N 2 S 2 donor set provided by two bidentate ligands and an O atom derived from a monodentate nitrate ligand, Table 1. The resulting N 2 S 2 O coordination geometry for the Cu1 atom is relatively close to a square pyramid as quantified by the value of τ = 0.15, which compares to the τ values of 0.0 and 1.0 for ideal square pyramidal and trigonal bipyramidal geometries, respectively (Addison et al., 1984). The value for the Cu2 atom, i.e. τ = 0.22, indicates a small deviation along the path towards trigonal bipyramidal. The τ value for the previously described  Table 2.
After reducing the volume and keeping overnight, a dark-blue product appeared, which was washed with ethanol (3 x 3 mL) and dried in a vacuum desiccator over silica gel. The product was recrystallized by dissoving the complex in ethanol (10 mL) and then layering this with petroleum ether (5 mL); M.pt: >493 K. The crystal structure determination showed that the original cyclic ligand had transformed to N-methyl-hydrazinecarbodithioic acid methyl ester (from which the cyclic form was prepared) during the course of the reaction.
supplementary materials

Figure 1
The molecular structures of the components comprising (I) showing the atom-labelling scheme and displacement ellipsoids at the 50% probability level. Overlay diagram of the two independent Cu-containing molecules comprising the asymmetric unit of (I). The first independent molecule (with the Cu1 atom) is shown in red. Also included is the molecule observed in the previously reported polymorph (green). The S-Cu-S residues in each molecule have been overlapped.  A view of the unit-cell contents in projection down the a axis in (I). The N-H···O and C-H···O interactions are shown as blue and orange dashed lines, respectively.

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.