trans-Chloridobis(ethane-1,2-diamine-κ2 N,N′)(thiocyanato-κN)cobalt(III) diamminetetrakis(thiocyanato-κN)cromate(III)

The title ionic complex [CoCl(NCS)(C2H8N2)2][Cr(NCS)4(NH3)2], which crystallizes as a non-merohedral twin, is build up of a complex cation [CoCl(NCS)(en)2]+ (en is ethane-1,2-diamine) and the Reinecke’s salt anion [Cr(NCS)4(NH3)2]− as complex counter-ion. A network of N—H⋯S and N—H⋯Cl hydrogen bonds, as well as short S⋯S contacts [3.538 (2) and 3.489 (3) Å], between the NCS groups of the complex anions link the molecules into a three-dimentional supramolecular network. Intensity statistic indicated twinning by non-merohedry with refined weighs of twin components are 0.5662:0.4338.

The crystals were filtered off, washed with dry PriOH and finally dried in vacuo at room temperature. Yield: 0.12 g, 17.1%.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 1. All of the hydrogen atoms were positioned geometricaly and refined using a riding model approximation with U iso = 1.2 or 1.5 U eq of the carrier atom. A rotating model was used for NH 3 and CH 3 groups. Intensity statistic indicated a nonmerohedral twinning with refined weights of twin components are 0.5662:0.4338.
As it shown on Fig.1 Co atom in complex cation is in distorted square bypiramidal coordination enviroment with one NCS group and chlorine atom at the axial positions and four N atoms from two ethylenediamine molecules in equatorial plane. The Cr centers are in the similar to Co coordination enviroment and coordinated to six N atoms -four NCS-groups in equatorial position and two NH 3 molecules in axial position. The bond distances and angles in the title molecule agree well with the corresponding bond distances and angles reported in closely related compounds (Schubert et al.,1981, Tang et al., 1993, Foust et al., 1980, Anbalagan et al., 2009, Nikitina et al., 2008). There are short interanionic S···S contacts between NCS-groups of the complex anions with the distances 3.538 (1) (S5···S5) and 3.489 (1) Å (S2···S2) whereas sum of standard Van-der-Vaals radius of the sulfur atom is 3.68 Å. Two NCS-groups of the ligand which involve S2 and S3 atoms show relatively large thermal displacements (U eq is 0.1063 (9) Å 2 and 0.0984 (8) Å 2 , resp.). Also these NCS-groups show notably non-linear Cr-N-C bond angles (166.2 (5)° and 163.2 (5)°).This might be caused by inter-  (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: publCIF (Westrip, 2010).

Figure 1
Crystal structure of the complex, showing the atom numbering, with 30% probability displacement ellipsoids

Figure 2
The crystal packing of the title compound. Hydrogen bonds are shown as dashed lines.