Tris{2-[(furan-2-methyl)iminomethyl]-4-methylphenolato}cobalt(III)

In title compound, [Co(C13H12NO2)3], the CoIII ion is six-coordinated by three bidentate Schiff base ligands in a distorted octahedral environment. Adjacent complex molecules are linked through C—H⋯O hydrogen bonds.


Comment
The Schiff base ligands may act as a bidentate N, O-(Castillo et al., 2003) anda tridentate N,O,O-donor ligand (Erxleben et al., 2001) in the coordination chemistry. In general, the Schiff base metal complexes possess antitumour activities (Ren et al., 2002;Liu et al., 1992) and antimicrobial (Panneerselvam et al., 2005). In addition, cobalt is an important life-required element. For example, vitamin B12, also called cobalamin, which is a water soluble vitamin with a key role in the normal functioning of the brain and nervous system, and for the formation of blood (Randaccio et al., 2010). By taking the biological importance of element cobalt into account, we designed the title complex with the bidentate N,O-donor Schiff base ligands (Scheme I).
The title complex reported here is the mononuclear cobalt(III) complex of the Schiff-base ligand, derived from the condensation of 5-methylsalicylaldehyde and furfuryl amine (Fig. 1). The cobalt(III) atom has a distorted octahedral coordination sphere. Cobalt(III) atom is six-coordinated by three imino N atoms and three phenolic O atoms from three bidentate Schiff-base ligands. Analogous octahedral Co(III) species were previously reported in the literatures (Ray et al., 2008;Sari et al., 1997;Olejnik et al., 1994). All bond lengths are within normal ranges (Allen et al., 1987). It is interesting to point out that the planes of the six-membered chelate rings coordinated to the same Co(III) ion were twisted by 76.41 (3)°, 70.99 (4)°, 84.60 (3)° with respect to each other.
In the crystal structure, the molecules are linked via intermolecular C-H···O hydrogen bonds (Fig.2).

Refinement
All the H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms, with C-H distances of 0.93-0.97 Å, and with U iso (H) = 1.2U eq (carrier) or 1.5U eq (methyl groups).

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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.