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

Wenju Wang; Youdi Zhang; Xiangjun Jin; Xiguang Du

doi:10.1107/S1600536809031626

. 2009 Aug 19;65(Pt 9):m1094. doi: 10.1107/S1600536809031626

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

Wenju Wang ^a,^*, Youdi Zhang ^b, Xiangjun Jin ^a, Xiguang Du ^b

PMCID: PMC2970040 PMID: 21577445

Abstract

The title compound, [MoF₂O₂(C₁₂H₈N₂)], 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—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.

Related literature

For the structure and mode of action of the co-factor of oxido-molybdoenzymes, 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 ▶).

Experimental

Crystal data

[MoF₂O₂(C₁₂H₈N₂)]
M _r = 346.14
Monoclinic,
a = 7.5190 (9) Å
b = 17.818 (2) Å
c = 9.5331 (11) Å
β = 110.8560 (10)°
V = 1193.5 (2) Å³
Z = 4
Mo Kα radiation
μ = 1.12 mm⁻¹
T = 295 K
0.30 × 0.30 × 0.20 mm

Data collection

Bruker APEXII diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.711, T _max = 0.799
6460 measured reflections
2394 independent reflections
2248 reflections with I > 2σ(I)
R _int = 0.023

Refinement

R[F ² > 2σ(F ²)] = 0.022
wR(F ²) = 0.065
S = 1.04
2394 reflections
173 parameters
H-atom parameters constrained
Δρ_max = 0.46 e Å⁻³
Δρ_min = −0.59 e Å⁻³

Data collection: APEX2 (Bruker, 2003 ▶); cell refinement: SAINT (Bruker, 2001 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg & Berndt, 1999 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809031626/si2192sup1.cif

e-65-m1094-sup1.cif^{(18.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809031626/si2192Isup2.hkl

e-65-m1094-Isup2.hkl^{(117.7KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected bond lengths (Å).

Mo1—O2	1.6874 (18)
Mo1—O1	1.6936 (17)
Mo1—F1	1.9017 (14)
Mo1—F2	1.9049 (13)
Mo1—N2	2.3257 (18)
Mo1—N1	2.3295 (18)

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Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C2—H2C⋯F1ⁱ	0.93	2.45	3.202 (3)	138
C3—H3C⋯O1ⁱⁱ	0.93	2.55	3.376 (3)	148
C7—H7⋯F1ⁱⁱⁱ	0.93	2.44	3.191 (3)	137
C8—H8⋯O2^iv	0.93	2.59	3.222 (3)	126

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) .

Acknowledgments

The authors gratefully acknowledge financial support from the Youth Fund of Northeast Normal University.

supplementary crystallographic information

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 MoO₂X₂ (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 1,10-phenanthroline 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 MoO₂X₂.2L 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 MoO₂X₂ (X = Cl, Br) complexes [For MoO₂Cl₂ complex, see: Viossat & Rodier, (1979); for MoO₂X₂.2L 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.

Experimental

A mixture of Molybdenum trioxide (0.2874 g, 2 mmol), HF (2 ml), 1,10-phenanthroline(0.2246 g, 1.1 mmol) and N,N-dimethylformamide (30 ml) was stirring for 7 h under 343 K. After cooling to room temperature, the mixture was adjusted to pH = 6.05 with 6 M H₂SO₄ solution. The filtration was allowed to stand over several days to give colorless block single crystals in 80% yield. Analysis calculated for C₁₂H₈F₂MoN₂O₂: C 41.64, H 2.33, N 8.09, F 10.98%; found: C 41.60, H 2.30, N 8.06, F 10.94%.