(2,6-Difluorobenzophenone)tris(trimethylphosphine)cobalt(0)

In the title compound, [Co(C13H8F2O)(C3H9P)3], the cobalt(0) atom is coordinated by three trimethylphosphine ligands and a π-coordinated carbonyl group of the 2,6-difluorobenzophenone ligand in a distorted tetrahedral geometry. The Co—O and Co—C distances are 1.896 (2) and 2.049 (4) Å, respectively.

In the title compound, [Co(C 13 H 8 F 2 O)(C 3 H 9 P) 3 ], the cobalt(0) atom is coordinated by three trimethylphosphine ligands and a -coordinated carbonyl group of the 2,6difluorobenzophenone ligand in a distorted tetrahedral geometry. The Co-O and Co-C distances are 1.896 (2) and 2.049 (4) Å , respectively.

Related literature
For general background to the activation of C-F bonds in organometallic chemistry and catalyst development, see: Kiplinger et al. (1994); Saunders (1996); Li et al. (2006).

Experimental
Crystal data [Co(C 13  supporting information Acta Cryst. (2009). E65, m495 [doi:10.1107 (2,6-Difluorobenzophenone)tris(trimethylphosphine)cobalt(0) Jun Ding and Xiao-Yan Li S1. Comment The activation of carbon-fluorine bonds is of great importance in organometallic chemistry and catalyst development because this type of reaction contributes tothe fundamental understanding of reactivity of stable bonds and selective replacement of F atoms (Kiplinger et al., 1994;Saunders, 1996). Recently we have reported cyclometalation reactions involving C-F bond activation at a cobalt(I) center with azine as an anchoring group, which afforded the first complex containing a C-Co-F fragment (Li et al., 2006).
We tried to synthesis compound I (Scheme 2) according to the route a in Fig. 2 throught the reaction of 2,6-difluorobenzophenone with tetra(trimethylphosphine)cobalt(0), but the reaction was actually occurred by route b (Scheme 2).
Compound II was isolated as red crystals and its molecular structure is shown in Fig. 1. The cobalt atom is π-coordinated with carbonyl group. The Co-O and Co-C bond lengths are 1.896 (2) Å and 2.049 (4) Å (Table 1).

S2. Experimental
The title compound was synthesized from the reaction of tetra(trimethyl phosphine)cobalt (1.2 g, 3.3 mmol) and 2,6-difluorobenzophenone (0.72 g, 3.3 mmol) in pentane (40 ml) for 24 h at 298 K. After filtration, the title complex was obtained from filtrate as red crystals at 246 K.

S3. Refinement
The H atoms were geometrically placed and treated as riding atoms with C-H = 0.96 Å and U iso (H)=1.5U eq (C) for methyl H atoms, C-H = 0.93 Å and U iso (H)=1.2U eq (C) for arometic H atoms.  The molecular structure of the title compound, displacement ellipsoids are drawn at the 25% probability level.  The formation of the title compound.
where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.38 e Å −3 Δρ min = −0.31 e Å −3 Extinction correction: SHELXL Extinction coefficient: 0.0037 (5) 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq C22 0.0242 (