cis-Bis[4-amino-N-(pyrimidin-2-yl)benzenesulfonamido-κ2 N,N′]bis(dimethyl sulfoxide-κO)cadmium

The complete molecule of the title compound, [Cd(C10H9N4O2S)2(C2H6OS)2], is completed by the application of a twofold rotation axis. The CdII atom is six coordinated by two bidentate sulfadiazinate anions and two dimethylsulfoxide molecules. The resulting N4O2 donor set displays a distorted trigonal–prismatic coordination geometry. The S atom and methyl groups of dimethylsulfoxide are disordered over two sets of sites, with site occupancies of 0.715 (4) and 0.285 (4). The crystal structure features intermolecular N—H⋯N and N—H⋯O hydrogen bonds that lead to the formation of layers in the ab plane.

The complete molecule of the title compound, [Cd(C 10 H 9 N 4 O 2 S) 2 (C 2 H 6 OS) 2 ], is completed by the application of a twofold rotation axis. The Cd II atom is six coordinated by two bidentate sulfadiazinate anions and two dimethylsulfoxide molecules. The resulting N 4 O 2 donor set displays a distorted trigonal-prismatic coordination geometry. The S atom and methyl groups of dimethylsulfoxide are disordered over two sets of sites, with site occupancies of 0.715 (4) and 0.285 (4). The crystal structure features intermolecular N-HÁ Á ÁN and N-HÁ Á ÁO hydrogen bonds that lead to the formation of layers in the ab plane.

cis-Bis
In an attempt to prepare a complex of sulfadiazine with the cadmium(II) ion in methanol by the reaction of a cadmium salt and sulfadiazine followed by crystallization from dimethylsulfoxide, the compound isolated was shown by crystallography to have the formula [Cd(C 10 H 9 N 4 O 2 S) 2 ](DMSO) 2 .
The six coordinate cadmium complex is trigonal prismatic, Fig. 1. The C18-N14 bond distance of 1.366 (5) Å and the C15-S11-N11-C11 torsion angle of 66.1 (3) ° are comparable to those observed in related structures (Heren et al., 2006;Hossain & Amoroso, 2007). The Cd-O bond distance is shorter than the Cd-N bonds ( Table 1). The dihedral angle between the aromatic rings of the anion of 88.65 (12) ° and this is greater than value of 71.10 (14) ° in the sulfadiazinate anion (Hossain & Amoroso, 2007). This is because in the latter the molecule is not bonded to a metal ion. The packing of (I) (Fig. 2) is stabilized by intermolecular N-H···N and N-H···O hydrogen bonds (Table 2) occurring between the anions in accord with a literature precedent (Paşaoğlu, et al., 2008). This hydrogen bonding leads to layers in the ab plane, Fig. 2.

Experimental
The sodium salt of sulfadiazine (5.446 g, 2 mmol) was dissolved in hot methanol (50 ml) and a methanol solution (10 ml) of (CH 3 COO) 2 Cd.2H 2 O (2.6647 g, 1 mmol) was added slowly with constant stirring on a hot plate. A white precipitate was formed and the mixture was stirred for a further 2 h. The precipitate was filtered off and dried over silica gel. It was then dissolved in dimethylsulfoxide solution (50 ml), Colourless blocks were filtered off and dried over silica gel.

Refinement
The S atoms and methyl groups of dimethylsulfoxide were disordered. This was modelled with two different orientations and from refinement the site occupancies were 0.715 (4):0.285 (4). The H atoms were positioned geometrically and refined using in the riding model approximation, with C-H = 0.95-0.98 Å, and with U iso (H) = 1.2 (1.5 for methyl groups) times U eq (C). The N-H H atoms were located from a difference map and refined freely. Fig. 1. The molecular structure of (I), with atom labels and 50% probability displacement ellipsoids for non-H atoms. The S atom and methyl groups of dimethylsulfoxide are disordered over two sites, with occupancies of 0.715 (4)