N,N,N′,N′-Tetramethylethylenediammonium tetrachloridocobaltate(II)

The asymmetric unit of the title compound, [(CH3)2NH(CH2)2NH(CH3)2][CoCl4], contains a tetrachloridocobaltate(II) dianion and two halves of two centrosymmetric, crystallographically-independent, dications. One independent dication is disordered between two conformations in a 0.784 (13):0.216 (13) ratio. In the crystal, intermolecular N—H⋯Cl hydrogen bonds link cations and anions into chains propagated in [01]. These hydrogen bonds contribute to the distorted tetrahedral geometry at the CoII atom.


Related literature
The synthesis of the title compound was modified from that of Szafran et al. (1998). Related tetramethylethylenediammonium salts are listed in the Cambridge Structural Database (Allen, 2002).

Experimental
Crystal data (C 6  129 parameters H-atom parameters constrained Á max = 0.53 e Å À3 Á min = À0.50 e Å À3 Table 1 Selected geometric parameters (Å , ).  Two different halves ("A" & "B" suffixes) of the cation are present in the asymmetric unit. The N/C/C/N sections of each cation are planar causing each half to be related to its partner half via a center of inversion in the middle of the cation.
Additionally, magnitudes of the corresponding torsion angles involving the methyls are somewhat comparable, but not equal.
Examination of the bond lengths and angles reveals numerous significant (\geq 3σ) differences between the "A" and "B" TMED cations. The "B" TMED exhibits disorder [0.784 (13); 0.216 (13)]. In both TMED cations the E conformation (likely due to the preference of dipoles within a molecule to oppose each other) of the methyls, nitrogen, and the amine H atoms shown in Fig. 1 contributes greatly not only to the presence of a center of inversion, but also to the one-dimensional hydrogen bonding present along [0-11].
A highly distorted tetrahedral geometry is present around the Co (cf. the six different Cl-Co-Cl angle values and four distances in Table 1). The ranges of distance and angle values are, respectively, 0.048 Å (\sim 64σ) and 9.21° (~230σ).
Two of the Cl's in the [CoCl 4 ] 2moiety are involved in hydrogen bonding with amine H's in either the asymmetric unit or symmetry-related amine H's (Table 2). In both "A" and "B" cations, short (~2.3 Å) H-bond distances are noted for each hydrogen and are shown in Fig. 1  In the final stages of refinement five reflections with very small or negative F o 's were deemed to be in high disagreement with their F c 's and were eliminated from final refinement. 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 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.