Bis(triethylammonium) tetrachloridocobaltate(II)

The crystal structure of the title compound, (C6H16N)2[CoCl4], is comprised of a tetrahedral [CoCl4]2− anion and two independent triethylammonium cations. The latter are featureless while the [CoCl4]2− anion exhibits typical Co—Cl bond lengths [2.2428 (15)–2.2847 (16) Å] and a Cl—Co—Cl angular range of 107.58 (6)–112.73 (7)°. In the crystal, N—H⋯Cl hydrogen bonds between the two crystallographically independent cations and the [CoCl4]2− anion generate discrete ion triplets. The two Co—Cl bonds involved in these interactions are slightly longer than the remaining two.


Related literature
For the crystal structure of a related complex, see: Clegg & Martin (2007).

Experimental
Crystal data (C 6 Table 1 Hydrogen-bond geometry (Å , ).  (7)°. An ORTEP diagram of the asymmetric unit is presented in Fig. 1. In the crystal structure intermolecular N-H-Cl hydrogen bonds are observed between each of the two crystallographically independent cations and the tetrahedral [CoCl 4 ] 2anion that generate discrete ion triplets ( Table 1). The Co-Cl bonds involving the hydrogen-bonded Cl atoms are slightly longer than the remaining two. The hydrogen bonds between the organic cations and the [CoCl 4 ] 2anions contribute to the stability of crystal packing (Fig. 2).

Experimental
The compound was obtained unexpectedly in an unsuccessful attempt to prepare a cobalt(II) macrocyclic Schiff-base complex. To 2,6-diformyl-4-chlorophenol (1 mmol) and CoCl 2 .6H 2 O (2 mmol) in 25ml of MeOH, a methanolic solution (25 ml) of 1,2-bis (2′-aminophenoxy)benzene (1 mmol) and NEt 3 (1 mmol) was added dropwise. The resulting solution was stirred under reflux for 3 h. The precipitate obtained by partial evaporation of the solution was allowed it to stand overnight in refrigerator and was collected by filtration. Suitable crystals for the X-ray crystal structure determination were grown by recrystallization by diffusion of diethylether in the solution of the complex in acetonitrile Refinement N-bound H atoms were located in a difference map and refined isotropically. Other H atoms were positioned geometrically and refined with a riding model (including free rotation about C-C bonds), with U iso (H) = 1.2 (1.5 for methyl groups) times U eq (C). Atoms C5 and C6 from one of the ethyl branches of the N1 cationic groups show large displacement factors, much larger than neighbouring atoms and (due to libration effects) giving rise to a short, non realistic C-C sp 3 ···sp 3 distance of 1.250 (9)Å.  The asymmetric unit with atom labels and 50% probability ellipsoids for non-H atoms. Hydrogen bonds are shown as dashed lines.

Figure 2
The packing, viewed along the c axis. Hydrogen bonds are shown as dashed lines, and H atoms not involved in hydrogen bonding have been omitted.

Bis(triethylammonium) tetrachloridocobaltate(II)
Crystal data (C 6  Special details Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes. 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 > 2σ(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Co 0.05270 (5)