Pentaaqua(acetonitrile-κN)zinc(II) 4,6-dihydroxybenzene-1,3-disulfonate trihydrate

In the title compound, [Zn(CH3CN)(H2O)5](C6H4O8S2)·3H2O, the ZnII ion lies on a mirror plane and is octahedrally coordinated by one acetonitrile ligand and five water molecules. The 4,6-dihydroxybenzene-1,3-disulfonate anion, acting as a counter-ion, is also located on the mirror plane. The crystal packing is stabilized by O—H⋯O hydrogen bonds, forming a three-dimensional supramolecular network.

In the title compound, [Zn(CH 3 CN)(H 2 O) 5 ](C 6 H 4 O 8 S 2 )Á-3H 2 O, the Zn II ion lies on a mirror plane and is octahedrally coordinated by one acetonitrile ligand and five water molecules. The 4,6-dihydroxybenzene-1,3-disulfonate anion, acting as a counter-ion, is also located on the mirror plane. The crystal packing is stabilized by O-HÁ Á ÁO hydrogen bonds, forming a three-dimensional supramolecular network.

Comment
Benzenesulfonic acid derivatives have been found wide range of applications in coordination chemistry as ligands, in medicinal chemistry and materials science. There has been an increased interest in the preparation of coordination compounds of benzenesulfonic acid derivatives (Arnold et al., 2001;Du et al., 2006;Junk & Steed, 2007;Xie et al., 2002;Zhang et al., 2009). We report here the crystal structure of the title compound.
The title compound is built up of one [Zn(C 2 H 3 N)(H 2 O) 5 ] 2+ cation, one uncoordinated 4,6-dihydroxybenzene-1,3-disulfonate anion and three uncoordinated water molecules (Fig.1). The distorted octahedral environment around the Zn II ion consists of one acetonitrile ligand and five water molecules. The Zn-O bond distances range from 2.058 (2) to 2.096 (3) Å. The average Zn-O bond distance of 2.078 Å and the Zn-N bond distance of 2.118 (3) Å are similar to the values in other zinc complex (Adarsh et al., 2008;Francis et al., 2003;Lu et al., 2008). The cations, anions and uncoordinated water molecules are linked into a three-dimensional supramolecular network by O-H···O hydrogen bonds (Table 1 and Fig. 2).

Experimental
Zn(CH 3 CO 2 ) 2 (0.5 mmol) and 4,6-dihydroxybenzene-1,3-disulfonic acid (0.5 mmol) were dissolved in a mixed solution of water (2 ml) and acetonitrile (16 ml). Colorless block crystals of the title compound suitable for X-ray analysis were obtained by evaporation of the solvent in air (yield 63% based on Zn).

Refinement
H atoms attached to C and O atoms were located in difference Fourier maps and were treated as riding on their parent atoms.
The displacement parameters of all H atoms were refined isotropically. Fig. 1