Bis[2-(2-pyridylmethyleneamino)benzenesulfonato-κ3 N,N′,O]zinc(II) dihydrate

In the title complex, [Zn(C12H9N2O3S)2]·2H2O, the ZnII ion lies on a crystallographic inversion center and is coordinated by four N atoms and two O atoms from two tridentate 2-(2-pyridylmethyleneamino)benzenesulfonate ligands in a slightly distorted octahedral environment. In the crystal structure, the complex forms a two-dimensional network through intermolecular O—H⋯O and C—H⋯O hydrogen bonds.

In the title complex, [Zn(C 12 H 9 N 2 O 3 S) 2 ]Á2H 2 O, the Zn II ion lies on a crystallographic inversion center and is coordinated by four N atoms and two O atoms from two tridentate 2-(2pyridylmethyleneamino)benzenesulfonate ligands in a slightly distorted octahedral environment. In the crystal structure, the complex forms a two-dimensional network through intermolecular O-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds.

Comment
The design and control of supermolecular coordination complex networks in which both coordination bonds and hydrogen bonds take part in the self-assembly chemistry (Zheng, et al., 2001;Zhou, et al., 2004) have recently garnered increasing interest. Schiff base complexes that contain both sulfur and amino acid functionalities have received much attention owing to their potential applications in pharmacy. (Casella & Gullotti, 1981, 1986Wang et al., 1994;Li et al., 2006;Zhang et al., , 2008. Our group has focused on the exploration of the coordination chemistry of the sulfonate ligands for years (Zhang et al. 2004;Jiang et al. 2006;Li et al. 2007). We report here the synthesis and the structure of the mononuclear Zn II Paba complex (Fig. 1). The structure is composed of one Zn II , two deprotonated Pabaligands and two guest water molecules.
The six-coordinated Zn II atom has a distorted octahedral geometry, being coordinated by pyridine N, imine N and sulfonate O atoms from two deprotonated Pabaligands in a tridentate facial arrangement. This structure is similar to those reported for complexes with N,N',O-tridentate donor ligands Correia et al., 2003).
There are extensive hydrogen bonds (O4-H2W···O2 and O4-H1W···O3), in which the donor is O-H of the guest water and S=O acts as acceptor, which forms a two-dimension sheet structure (Fig. 2).
To prepare the title complex, the ligand PabaK (1 mmol, 0.30 g) was dissolved in methanol (10 mL) at 333 K and an aqueous solution (10 mL) containing ZnCl 2 (0.5 mmol, 0.068 g) was added. The resulting solution was stirred at 333 K for 4 h, then cooled to room temperature and filtered. Yellow crystals suitable for X-ray diffraction were obtained by slow evaporation over several days, with a yield of 55%. Elemental analysis, found ( Crystal data [Zn(C 12

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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.