Bis(morpholin-4-ium) tetrachloridocobalt(II)

The title compound, (C4H10NO)2[CoCl4], is an ionic compound consisting of two protonated tetrahydro-1,4-oxazine (morpholine) cations and a [CoCl4]2− dianion. The CoII ion is in a tetrahedral coordination geometry. The cations exhibit chair-shaped conformations. A three-dimensional supramolecular architecture is formed through N—H⋯Cl and C—H⋯Cl hydrogen bonds between the dianions and the cations.

The title compound, (C 4 H 10 NO) 2 [CoCl 4 ], is an ionic compound consisting of two protonated tetrahydro-1,4oxazine (morpholine) cations and a [CoCl 4 ] 2À dianion. The Co II ion is in a tetrahedral coordination geometry. The cations exhibit chair-shaped conformations. A three-dimensional supramolecular architecture is formed through N-HÁ Á ÁCl and C-HÁ Á ÁCl hydrogen bonds between the dianions and the cations.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: PK2366).  Oligo-α-pyridylamine ligands are very useful in the synthesis of metal string complexes, which are also known as extended metal atom chains (EMACs). EMACs are invaluable for acquiring a fundamental understanding of metal-metal bonds (Kiehl et al., 2004) and for potential applications such as molecular electronic devices. These oligo-α-pyridylamine ligands contain pyridyl and amine groups, and can result in the formation of double helical structures in nonpolar solvents due to hydrogen bonding (Leung et al., 2002). After deprotonation of oligo-α-pyridylamine ligands, the resulting anions can stabilize the linear metal cores. Activation of the H atom was observed in some EMACs. Recently we designed a series of modulated oligo-a-pyridylamino ligands, by including one or more of the nitrogen-rich aromatic rings such as pyrazine, pyrimidine and naphthyridine instead of pyridine rings to the ligands. The modification of ligands significantly improved the reactivity leading to the EMAC, and resulted in complexes with very different redox properties (Wang et al., 2008). Furthermore, by providing more donor nitrogen atoms in aromatic rings, the pyrazine ligands exhibit more coordination forms and are especially versatile in the construction of coordination polymers with potential applications in gas storage, catalysis, magnetism, luminescence, etc. due to their ability to form multidimensional frameworks through multiple metal-binding sites. Wang et al., 2007Wang et al., , 2008. Some interesting phenomena were also observed, e.g. the observation of disassembly of ligands during the preparation of EMACs. In this paper we describe a compound (I) from the decomposition of pyrazine-modulated N 2 -(pyrazin-2-yl)-N 6 -(6-(pyrazin-2-ylamino)pyridin-2-yl)pyridine-2,6-diamine (H 3 pzpz) relating to the preparation of heptacobalt complexes .  (Fastje & Möller, 2009;Szklarz et al., 2009;Wu et al., 1997).
The cations are six-membered heterocycle rings, protonated tetrahydro-1,4-oxazine, and exhibit chair-shaped conformations. All bond angles in the rings are in the range 108.8 (3) -111.9 (2)° with an average of 110.4 (3)°, which is well consistent with a sp 3 hybrid orbital angle. The nitrogen atom in tetrahydro-1,4-oxazine was protonated owing to the low basicity of tetrahydro-1,4-oxazine (pK a = 8.4) due to the inductive effect of oxygen atom. The average C-C, C-N and C-O bond distances exhibit a typical value of single bonds, which are 1.503 (4), 1.490 (4) and 1.419 (4) Å, respectively.

Experimental
Anhydrous CoCl 2 (254 mg, 1.95 mmol), H 3 pzpz (300 mg, 0.84 mmol) and naphthalene (65 g) were placed in an Erlenmeyer flask. The mixture was heated under argon and then a solution of potassium tert-butoxide (311 mg, 2.77 mmol) in n-butyl alcohol (5 ml) was added dropwise. The reaction was continued for another 12 h. After cooling the product was transferred to hexane to wash out the remaining naphthalene, and then 100 ml ca CH 2 Cl 2 was used to extract the complex. A dark green product, mainly the heptacobalt(II) metal string complex, [Co 7 (µ 7 -pzpz) 4 Cl 2 ], was obtained after evaporation. The title compound was obtained as a side product from the reaction. Light blue single crystals suitable for X-ray diffraction were obtained by diffusion of ether into a chloroform solution of the green product.

Refinement
H atoms attached to C and N atoms were positioned geometrically and refined using a riding model, with C-H = 0.99 Å, N-H = 0.92Å and U iso (H) = 1.2Ueq(C,N). Fig. 1. The molecular structure of (I) with ellisoids at the 30% probability level.

supplementary materials sup-3 Bis(morpholin-4-ium) tetrachloridocobalt(II)
Crystal data (C 4  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 Rfactors(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.