Chloridobis[diphenylglyoximato(1–)-κ2 N,N′](1H-imidazole-κN 3)cobalt(III) hemihydrate

The Co centre in the title compound, [Co(C14H11N2O2)2Cl(C3H4N2)]·0.5H2O, shows a slightly distorted octahedral coordination geometry. The glyoximate units of the molecule are linked by O—H⋯O hydrogen bonds with the H atom almost in the middle of the two O atoms. The crystal packing is stabilized through intermolecular N—H⋯O, N—H⋯N and O—H⋯Cl hydrogen bonds. The uncoordinated water molecule shows half-occupation.

The Co centre in the title compound, [Co(C 14 H 11 N 2 O 2 ) 2 Cl-(C 3 H 4 N 2 )]Á0.5H 2 O, shows a slightly distorted octahedral coordination geometry. The glyoximate units of the molecule are linked by O-HÁ Á ÁO hydrogen bonds with the H atom almost in the middle of the two O atoms. The crystal packing is stabilized through intermolecular N-HÁ Á ÁO, N-HÁ Á ÁN and O-HÁ Á ÁCl hydrogen bonds. The uncoordinated water molecule shows half-occupation.

S1. Comment
The coordination geometry around cobalt is octahedral with the four nitrogen atoms of the diphenyl glyoximato ligand forming an approximate square plane. The bite angles N1-Co-N2 and N3-Co-N4 of the ligand are 81.40 (10)° and 80.32 (10)°, respectively. The coordinating chlorine and imidazole nitrogen [N5-Co1-Cl1 = 179.11 (7)°] are perpendicular to the equatorial plane composed by the four N atoms. The two glyoximate moieties are linked by strong O -H···O hydrogen bonds. Similar hydrogen bonds are found in nickel(II)glyoximate (Calleri, et al., 1967). The molecule is linked to its b-glide equivalent through a N-H···O hydrogen bond The water molecule forms a short O-H···Cl contact.

S2. Experimental
Cobaltous chloride hexahydrate was thoroughly ground and exposed to microwave for 30 s. The dehydrated salt was mixed with diphenylglyoxime in 1:2 molar ratio in acetone medium and was stirred for an hour (Toscano, et al., 1983;Gupta, et al., 2001). Since the dichloro complex of diphenyl glyoxime was non-isolable, the complex solution was as such refluxed with equimolar ratio of imidazole for six hours to get the title compound. The resulting brown mass was filtered, washed with ether and dried in a vaccuum desiccator. The complex was dissolved in ethanol and kept in a dark room for crystallization. Brown crystals of the complex appeared in three days. The elemental analysis data, obtained by analytical methods agree well with the theoretical data expected for the formula of the complex proposed: Anal%, (cald%): C, 62.07(62.57); H, 4.82(4.71); N, 14.50(14.13). The C=N stretching vibration of oxime in the complex was observed at 1629 cm -1 and the intra molecular hydrogen bonded OH around 3400 cm -1 . A moderate peak around 1252 cm -1 may be assigned to the C=N-O stretching of the oxime. The peak around 537 cm -1 could be attributed to cobalt(III)-nitrogen stretching. The 1 H NMR spectra of the complex in acetone-d 6 shows three different signals corresponding to diphenyl glyoximate ring protons (Gupta, et al., 2004;Lopez, et al., 1991). The ortho H atoms of the ring shows a doublet at d= 7.4 p.p.m., the meta protons and the para proton give triplets at d = 7.6 and 7.9 p.p.m.

S3. Refinement
All the hydrogen atoms could be located in difference Fourier maps. Nevertheless, the phenyl H atoms were  The ORTEP representation

Figure 2
Packing of molecules in the unit cell. Hydrogen bonds are shown with dotted lines.

Chloridobis[diphenylglyoximato(1-)-κ 2 N,N′](1H-imidazole-κN 3 )cobalt(III) hemihydrate
Crystal data [Co(C 14   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.

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