Bis(4-aminobenzenesulfonamide-κN 4)dichloridozinc

In the title compound, [ZnCl2(C6H8N2O2S)2], the ZnII ion lies on a twofold rotation axis and has a slightly distorted tetrahedral coordination geometry, involving two Cl atoms and two N atoms from the amino groups attached directly to the benzene rings [Zn—Cl = 2.2288 (16) Å and Zn—N = 2.060 (5) Å]. The dihedral angle between the benzene rings is 67.1 (3)°. The crystal packing can be describe as layers in a zigzag arrangement parallel to (001). The amine H atoms act as donor atoms and participate in intermolecular N—H⋯O and N—H⋯Cl hydrogen bonds, forming a three-dimensional network.

The molecular geometry and the atom-numbering scheme are shown in Fig 1. The title compound is a mononuclear zinc(II) complex in which the Zn II ion is in a slightly distorted tetrahedral geometry involving two Cl atoms and two N atoms from the two amino groups of the sulfanilamide unit [Zn-Cl = 2.2288 (16) Å and Zn-N = 2.060 (5) Å]. The angles involving the Zn atom range from 104.38 (14) to 116.38 (11)°. The dihedral angle between the two benzene rings is 67.1 (3)°. The crystal packing can be describe by a interacting layers in zigzag parallel to (001) planes (Fig.2). The sulfonamidic nitrogen atoms, acting as donor, participate in intermolecular N-H···O and N-H···Cl hydrogen bonds formimg a three-dimensional network (Table 1, Fig. 3).

Experimental
ZnCl 2 (0.1 mmol) and sulfanilamide (0.5 mmol) were dissolved in 15 ml solution of NaOH 0.01 N and heated, under continuous stirring, at 373 K for 15 min. The solution was transfered into a 23 ml teflon-lined stainless steel autoclave and heated at 453 K for 3 days. Then the autoclave was cooled to room temperature at 10K/h. Clear block-shaped crystal were collected, washed with ethanol and dried in air at ambient temperature.

Refinement
All non-H atoms were refined with anisotropic atomic displacement parameters. Approximate positions for all H atoms were first obtained from the difference electron density map. However, the H atoms were situated into idealized positions and the H-atoms have been refined within the riding atom approximation. The applied constraints were as follows: C-H = 0.93 Å and N-H = 0.90 Å. U iso = 1.2U eq (C or N). The atoms H1N and H2N amino group were located in difference Fourier maps and included in the subsequent refinement with the constaint of N-H = 0.85 (2)Å and U iso (H) = 1.5U eq (N).

Figure 2
Packing of (I) viwed via a axis showing alterning layers in zigzag parallel to (001) planes.

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.