Bis(thiosemicarbazide)nickel(II) bis[2-(thiosemicarbazonomethyl)benzenesulfonate] dihydrate

In the title compound, [Ni(CH5N3S)2](C8H8N3O3S2)2·2H2O, the NiII atom lies on a inversion centre and is four-coordinated by two N and two S atoms of two thiosemicarbazide ligands in an almost square-planar coordination. In the crystal structure, the molecules are linked into a three-dimensional network via C—H⋯O, C—H⋯N, N—H⋯O, N—H⋯S and O—H⋯O hydrogen bonds.

In the title compound, [Ni(CH 5 N 3 S) 2 ](C 8 H 8 N 3 O 3 S 2 ) 2 Á2H 2 O, the Ni II atom lies on a inversion centre and is four-coordinated by two N and two S atoms of two thiosemicarbazide ligands in an almost square-planar coordination. In the crystal structure, the molecules are linked into a three-dimensional network via C-HÁ Á ÁO, C-HÁ Á ÁN, N-HÁ Á ÁO, N-HÁ Á ÁS and O-HÁ Á ÁO hydrogen bonds.

Related literature
For the design and synthesis of organic-inorganic hybrid materials and their potential practical applications, see: Hagrman et al. (1998); Ranford et al. (1998).

S1. Comment
The design and synthesis of organic/inorganic hybrid materials have attracted intense attention in recent years owing to their potential practical applications, such as antitumor, antidiabetic, antitubercular activities, magnetism and catalysis (Ranford, et al., 1998;Hagrman, et al., 1998). In order to achieve supramolecular transition metal complexes by selfassembly, and to explore the relationship between the structure and the biological properties, as one part of our systematic work, in this paper, we report on the synthesis and crystal structure of the title compound, (I).
As shown in Fig. 1, the Ni II atom lies on a inversion centre and it is four-coordinate with two N donors and two S donors of two thiosemicarbazide ligands, and adopts distorted square coordination. The bond distances of Ni1-N5 (7)Å] are consistent with the bond lengths reported previously. The bond distances of Ni1-N5 (N5A) are shorter than the Ni1-S3 (S3A), showing that the strength of Ni1-N5 (N5A) are stronger than the Ni1-S3(S3A) ( Table 1). In the crystal packing, the molecules form a one-dimensional chain structure by the C-H···O, N-H···O, N-H···S and O-H···O hydrogen bonds (Table 2).

S2. Experimental
The solution of 1.0 mmol 2-formyl-benzenesulfonate-thiosemicarbazide was added to a solution of 0.5 mmol Ni(NCS) 2 .4H 2 O in 5 ml ethanol at room temperature. The mixture was refluxed for 4 h with stirring, then the resulting precipitate was filtered, washed, and dried in vacuo over P 4 O 10 for 48 h. Single crystals suitable for X-ray structural analysis was obtained by slowly evaporating from methanol at room temperature.  The molecular structure of (I) showing 30% displacement ellipsoids.

Bis(thiosemicarbazide)nickel(II) bis[2-(thiosemicarbazonomethyl)benzenesulfonate] dihydrate
Crystal data [Ni(CH 5 (11)  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.