Bis(acetato-κO)bis(thiourea-κS)cobalt(II)

The title compound, [Co(CH3COO)2(CH4N2S)2], is isotypic with the corresponding ZnII complex. The metal atom is in a distorted tetrahedral coordination environment with the two S atoms from two thiourea ligands and two O atoms from two acetate anions as the coordinating atoms. All H atoms of the thiourea ligands are involved in N—H⋯O and N—H⋯S hydrogen bonds, leading to a three-dimensional network.

The title compound, [Co(CH 3 COO) 2 (CH 4 N 2 S) 2 ], is isotypic with the corresponding Zn II complex. The metal atom is in a distorted tetrahedral coordination environment with the two S atoms from two thiourea ligands and two O atoms from two acetate anions as the coordinating atoms. All H atoms of the thiourea ligands are involved in N-HÁ Á ÁO and N-HÁ Á ÁS hydrogen bonds, leading to a three-dimensional network.

Related literature
For the isotypic Zn II compound, see: Cavalca et al. (1967). For a definition of tetrahedral distortion, see: Robinson et al. (1971).
The X-ray diffractometer has been financed by the Netherlands Organization for Scientific Research (NWO).
Supporting information for this paper is available from the IUCr electronic archives (Reference: SJ5387).

Comment
The crystal structure of bisthiourea-zinc acetate has been described in the literature in the centrosymmetric space group P2 1 /c (Cavalca et al., 1967). The corresponding cobalt compound was mentioned to be isotypic but no coordinates or further structural information were given. We therefore set out to crystallize the title compound and to determine its crystal structure.
It could indeed be confirmed that the title compound is isotypic with the zinc complex from the literature. The coordinates of the Zn compound were used as starting model for the least-squares refinement of the present Co structure.
The metal center is in a distorted tetrahedral environment with two S atoms from two thiourea ligands and two O atoms from two acetate molecules as coordinating atoms ( Figure 1). Coordination angles between 95.07 (2) and 117.69 (3) ° lead to an angle variance (Robinson et al., 1971) of 81.93 °2. The two Co-S distances are equal within standard uncertainties and are, as expected, longer than the Co-O distances. With a difference of 0.0385 (11) Å, the Co1-O1 distance is significantly longer than the Co1-O3 distance. A possible explanation for this difference are the hydrogen bonding interactions (Table 2). O1 the is acceptor of two hydrogen bonds, while O3 is the acceptor of only one.
A comparison of the Co environment of the present study with the Zn environment from the literature (Cavalca et al., 1967) remains inconclusive because of the large standard uncertainties of the Zn structure, which had been obtained at room temperature from film data. The difference in the two metal-S distances described for the Zn complex could not be detected in the Co complex (see Table).
The quality of the present low-temperature study allowed a detailed analysis of the H atoms. In the difference-Fourier maps, the two methyl groups of the acetate ligands appeared to be orientationally disordered. In the refinement, an idealized disorder model was used with a 60 ° rotation between the disorder forms. This disorder model was allowed to rotate about the C-C bond, and the H atom occupancies were refined. In the case of C3, the major disorder form has an occupancy of 0.881 (17)  direction via centrosymmetric ring-type hydrogen bonds involving H1 and H4 (graph set R 2 2 (16), symmetry code 1 -x, -y, -z), and H3 (graph set R 2 2 (8), symmetry code -x, -y, -z). H6 is involved in an intramolecular hydrogen bond with O2 as acceptor. Overall this is a hydrogen bonded three-dimensional network. 2. Experimental 0.23 g Cobalt(II) acetate tetrahydrate (0.92 mmol) and 0.14 g thiourea (1.84 mmol) were dissolved in deionized water and slowly evaporated at room temperature. Colourless needle-shaped crystals of thiourea and blue block-shaped crystals of the title compound were obtained.

Refinement
The methyl groups were refined with a model of perfect disorder using the SHELXL instruction AFIX 127. The occupancies of the disorder components were refined and the sum of the occupancies was constrained to 1. The H atoms of the thiourea ligands were refined freely with isotropic displacement parameters.