(Acetato-κO)(acetato-κO,O′)bis(1,3-diazinane-2-thione-κS)cadmium(II)

In the title complex, [Cd(CH3COO)2(C4H8N2S)2], the CdII cation is coordinated by three acetate O atoms and two S atoms of Diaz [Diaz = 1,3-diazinane-2-thione = 3,4,5,6-tetrahydropyrimidine-2(1H)-thione]. The CdII coordination is augmented by one considerably longer Cd—O bond of 2.782 (3) Å to a carboxylate O atom. The resulting coordination polyhedron around the CdII cations can be described as a highly distorted octahedron. The Diaz ligand and the acetate anions are linked by N—H⋯O hydrogen-bonding interactions.


Related literature
Data collection: SMART (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: publCIF (Westrip, 2010  The structural reports on cadmium(II) complexes of thiones describe that in most of the cases, the cadmium(II) complexes exist as neutral monomeric (Ahmad et al. 2011(Ahmad et al. , 2012Beheshti et al., 2007;Lobana et al. 2008;Nawaz et al., 2010;Wazeer et al., 2007) or polymeric (Moloto et al., 2007;Wang et al., 2002) with cadmium atom possessing a tetrahedral or distorted octahedral coordination environment respectively. In continuation of our studies on the structural chemistry of cadmium(II) complexes with thione ligands, we report here the crystal structure of the title compound. The crystal structure of the title complex ( Figure 1) consists of discrete monomeric species in which the Cd(II) ion is bound to two sulfur Diaz atoms, two oxygen atoms belonging to a chelating acetate and a third oxygen atom of a second acetate anion. The Cd-S bond distances are 2.5787 (8) and 2.529 (1) Å respectively while the Cd-O bond distances are in the range of 2.266 (2)-2.421 (2) Å. In addition, a secondary bonding interaction takes place with the second oxygen of one acetate anion with a distance of 2.782 (3) Å. The van der Waals radii for cadmium and oxygen are 1.58 and 1.52 Å respectively (Bondi, 1964). Considering the secondary bonding, the geometry could be considered as highly distorted  (Table 1).

Experimental
The title complex was prepared by adding 0.24 g (2.0 mmol) of 1,3-diazinane-2-thione in 15 ml of methanol to an aqueous solution (5 ml) of 0.26 g (1.0 mmol) cadmium sulfate in water followed by addition of 2 equivalents of sodium acetate in 10 ml water and stirring the mixture for 30 minutes. The colorless solution was filtered and the filtrate was kept at room temperature for crystallization. As a result, white crystalline product was obtained, that was washed with methanol and dried.

Refinement
All H atoms were placed in calculated positions and were refined isotropic with U iso (H) = 1.2U eq (C,N) (1.5 for methyl H atoms) using a riding model with C-H distances of 0.96 Å and 0.97 Å and N-H distances of 0.86 Å. program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication:

Figure 1
Molecular structure of the title compound showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level and dashed lines indicate intramolecular hydrogen bonding and the secondary Cd···O interaction.

(Acetato-κO)(acetato-κO,O′)bis(1,3-diazinane-2-thione-κS)cadmium(II)
Crystal data 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 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.