Bis(2-aminobenzonitrile)tetraaquacobalt(II) dichloride

In the crystal structure of the title compound, [Co(C7H6N2)2(H2O)4]Cl2, the CoII cation lies on an inversion center and is coordinated by two 2-aminobenzonitrile ligands and four water molecules in a distorted octahedral geometry. The Cl− counter-anion links with the complex cations via O—H⋯Cl and N—H⋯Cl hydrogen bonding. Intermolecular O—H⋯N hydrogen bonding links the complex cations, forming supramolecular chains running along the b axis.

In the crystal structure of the title compound, [Co(C 7 H 6 N 2 ) 2 -(H 2 O) 4 ]Cl 2 , the Co II cation lies on an inversion center and is coordinated by two 2-aminobenzonitrile ligands and four water molecules in a distorted octahedral geometry. The Cl À counter-anion links with the complex cations via O-HÁ Á ÁCl and N-HÁ Á ÁCl hydrogen bonding. Intermolecular O-HÁ Á ÁN hydrogen bonding links the complex cations, forming supramolecular chains running along the b axis.

Bis(2-aminobenzonitrile)tetraaquacobalt(II) dichloride
Zong-Ling Ru and Guo-Xi Wang S1. Comment Nitrile derivatives have found wide range of applications in industry and coordination chemistry as ligands. For example, phthalonitriles have been used as starting materials for phthalocyanines (Jin et al., 1994), which are important components for dyes, pigments, gas sensors, optical limiters and liquid crystals, and which are also used in medicine, as singlet oxygen photosensitisers for photodynamic therapy (Brewis et al., 2003). Recently, we have reported a few benzonitrile compounds (Fu & Zhao, 2007). As an extension of our work on the structural characterization, we report here the crystal structure of the title compound tetra-aqua-bis(2-aminobenzonitrile)-cobalt(II) dichloride.
The crystal data show that in the title compound, the Co(II) lies on an inversion center. The distorted octahedral Co(II) environment contains two N atoms from two planar trans-related 2-aminobenzonitrile ligands in the axial positions and four aqua O atoms in the equatorial plane. In the crystal, O-H···Cl, N-H···Cl and O-H···N hydrogen bonds generate an infinite two-dimensional network (Fig.1).

S2. Experimental
A mixture of 2-aminobenzonitrile (0.1 mmol) and CoCl 2 (0.1 mmol) and water (1 ml) sealed in a glass tube were maintained at 343 K. Crystals suitable for X-ray analysis were obtained after 5 d.

S3. Refinement
H atoms attached to C atoms were located geometrically and treated as riding with C-H = 0.93 Å, U iso (H) = 1.2U eq (C).
H atoms bonded to O and N atoms were located in a difference Fourier map and refined with distance restraints of O-H = 0.85±0.03 and N-H = 0.89±0.03 Å, U iso (H) = 1.5U eq (O,N).

Figure 1
A view of the title compound with the atomic numbering scheme. Displacement ellipsoids were drawn at the 30% probability level. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.30 e Å −3 Δρ min = −0.35 e Å −3 Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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 > σ(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.