[(E)-But-2-enoato-κO]chlorido(2,2′-diamino-4,4′-bi-1,3-thiazole-κ2 N 3,N 3′)zinc(II) monohydrate

In the title compound, [Zn(C4H5O2)Cl(C6H6N4S2)]·H2O, the ZnII cation is coordinated by a bidentate diaminobithiazole (DABT) ligand, a but-2-enoate anion and a Cl− anion in a distorted tetrahedral geometry. Within the DABT ligand, the two thiazole rings are twisted to each other at a dihedral angle of 4.38 (10)°. An intramolecular N—H⋯O interaction occurs. The centroid–centroid distance of 3.6650 (17) Å and partially overlapped arrangement between nearly parallel thiazole rings of adjacent complexes indicate the existence of π–π stacking in the crystal structure. Extensive O—H⋯Cl, O—H⋯O, N—H⋯Cl and N—H⋯O hydrogen bonding helps to stabilize the crystal structure.

In the title compound, [Zn(C 4 H 5 O 2 )Cl(C 6 H 6 N 4 S 2 )]ÁH 2 O, the Zn II cation is coordinated by a bidentate diaminobithiazole (DABT) ligand, a but-2-enoate anion and a Cl À anion in a distorted tetrahedral geometry. Within the DABT ligand, the two thiazole rings are twisted to each other at a dihedral angle of 4.38 (10) . An intramolecular N-HÁ Á ÁO interaction occurs. The centroid-centroid distance of 3.6650 (17) Å and partially overlapped arrangement between nearly parallel thiazole rings of adjacent complexes indicate the existence ofstacking in the crystal structure. Extensive O-HÁ Á ÁCl, O-HÁ Á ÁO, N-HÁ Á ÁCl and N-HÁ Á ÁO hydrogen bonding helps to stabilize the crystal structure.

Related literature
For the potential applications of metal complexes of diaminobithiazole in the biological field, see: Waring (1981); Fisher et al. (1985). For dihedral angles between thiazole rings in diaminobithiazole complexes, see: Du et al. (2010); Zhang et al. (2006).
The molecular structure of the title compound is shown in Fig. 1. The Zn II cation is coordinated by a diaminobithiazole (DABT) ligand, a but-2-enoate anion and a Clanion in a distorted tetrahedral geometry (Table 1). Within the DABT ligand the two thiazole rings are twisted to each other at a dihedral angle of 4.38 (10)°, which agrees with 9.51 (17)° found in a Pb II complex of DABT (Du et al., 2010) and 9.5 (2)° found in a Cd II complex of DABT (Zhang et al., 2006). The partially overlapped arrangement of centroids distance of 3.6650 (17) Å between nearly parallel thiazole rings of the adjacent complexes indicate the existence of π-π stacking in the crystal structure (Fig. 2). The extensive hydrogen bonding help to stabilize the crystal structure (Table 2).

Experimental
A water-ethanol solution (20 ml, 1:1) of DABT (0.10 g, 0.5 mmol) and ZnCl 2 (0.07 g, 0.5 mmol) was refluxed for 10 min, then an aqueous solution (20 ml) of (E)-but-2-enoatic acid (0.09 g, 1 mmol) and NaOH (0.04 g, 1 mmol) was mixed with the above solution. The mixture was refluxed for 6 h and then filtered. The single crystals of the title compound were obtained from the filtrate after a week.

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 > σ(F 2 ) is used only for calculating Rfactors(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.