Difluoridodioxido(1,10-phenanthroline)molybdenum(VI)

The title compound, [MoF2O2(C12H8N2)], has non-crystallographic mirror symmetry. The MoVI atom shows a distorted octahedral environment, with the phenanthroline N atoms and the two oxide groups forming the equatorial plane and the F atoms occupying the apical positions. Weak C—H⋯O and C—H⋯F hydrogen-bonding contacts and π–π interactions [centroid–centroid distance = 3.662 (1) Å] connect the complex molecules into a three-dimensional supramolecular framework.

The title compound, [MoF 2 O 2 (C 12 H 8 N 2 )], has non-crystallographic mirror symmetry. The Mo VI atom shows a distorted octahedral environment, with the phenanthroline N atoms and the two oxide groups forming the equatorial plane and the F atoms occupying the apical positions. Weak C-HÁ Á ÁO and C-HÁ Á ÁF hydrogen-bonding contacts andinteractions [centroid-centroid distance = 3.662 (1) Å ] connect the complex molecules into a three-dimensional supramolecular framework.

Related literature
For the structure and mode of action of the co-factor of oxidomolybdoenzymes, see: Collison et al. (1996). For the catalyst precursors, see Villata et al. (2000). For the dichloridodioxo analogue of the title compound, see: Viossat & Rodier (1979). For other related structures with the chelating phenanthroline ligand, see: Butcher et al. (1979); Bingham et al. (2006); Zhou et al. (2000).

Comment
The high oxidation state oxomolybdenum(VI) can be potentially used as molybdoenzyme, oxo transfer agents, and catalyst precusors [Collison, et al., (1996) ;Villata, et al., (2000)]. Though some MoO 2 X 2 (X = Cl, Br) complexes have been reported [Butcher, et al. (1979)], these compounds are usually unstable in air. Thus, the air stable dioxomolybdenum(VI) complex remains an intriguing area for chemists [Bingham, et al. (2006)]. In this paper, we reported a new fluorin containing oxomolybdenum(VI) complex that is stable in air.
As shown in Fig. 1, the title complex exhibits non-crystallographic molecular mirror symmetry. The distorted octahedral environment around molybdenum consists of cis terminal oxygen atoms (O t ) and trans fluorin atoms and bidentate 1,10phenanthroline ligand. One mirror plane can be seen bisecting the atoms F1-Mo1-F2 and extending through the midpoints of the central C-C bonds of the phenanthroline ligand, while another mirror can be imagined within the phenanthroline plane and the Mo and dioxo atoms. The average Mo-O t bond distance of 1.691 Å (Table 1) is a typical molybdenum-oxygen terminal double bond and is similar to those observed in MoO 2 X 2 .2L complexes [Butcher, et al. (1979)]. The Mo-N bond distances (2.326 (2) Å and 2.330 (2) Å) are also similar to those values observed in analogue complexes [Bingham, et al. (2006); Viossat & Rodier, (1979)]. However, the Mo-F bond distances of 1.905 (1) Å and 1.902 (1) Å for the title compound are transparently shorter than the Mo-Cl or Mo-Br bonds determined in other MoO 2 X 2 (X = Cl, Br) complexes [For MoO 2 Cl 2 complex, see: Viossat & Rodier, (1979); for MoO 2 X 2 .2L complexes, see : Butcher, et al. (1979)]. This is the main reason that the title compound is stable in air. Furthermore, there also exist weak C-H···F and C-H···O hydrogen bonding interactions between neighboring molecules which plays an important role to consolidate the supramolecular structure of the title compund. The detailed hydrogen bond parameters are shown in Table 2. Molybdenum and 1,10-phenanthroline complexes were substantively reported [Zhou,et al. (2000); Viossat & Rodier, (1979);Butcher, et al. (1979)], but it was quite missing that some references described the distinctive nature or features of π-π interaction. Whereas for the title complex, the 1,10-phenanthroline phenyl ring induced π-π interaction is demonstrated to aid the three-dimensional structure together with the weak hydrogen bonding contacts (Fig. 2). The centroid to centroid distance is 3.6619 (14) Å. (Cg3···Cg3îii^, Cg3 is the centroid of the ring (N2 C9 C8 C7 C6 C10), symmetry code iii = 1 -x, 1 -y, -z). The perpendicular distance of the rings is 3.369 Å and the slippage between the rings is 1.435 Å.

Difluoridodioxido(1,10-phenanthroline)molybdenum(VI)
Crystal data [ 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.