(2,2-Dichloro­vinyl)ferrocene

Sébastien Clément; Laurent Guyard; Michael Knorr; Viktoria H Gessner; Carsten Strohmann

doi:10.1107/S1600536809006102

. 2009 Feb 28;65(Pt 3):m334. doi: 10.1107/S1600536809006102

(2,2-Dichlorovinyl)ferrocene

Sébastien Clément ^a, Laurent Guyard ^a, Michael Knorr ^a, Viktoria H Gessner ^b, Carsten Strohmann ^b,^*

PMCID: PMC2968422 PMID: 21582103

Abstract

The title compound, [Fe(C₅H₅)(C₇H₅Cl₂)], represents a versatile building block for the preparation of π-conjugated redox-active compounds or polymetallic organometallic systems due to the presence of the electrochemically active ferrocenyl unit. It is therefore a potential starting material for the preperation of the corresponding alkyne. In the crystal, the alkenyl unit and the cyclopentadienide ring are almost parallel, with an angle between the best planes of only 10.6 (4)°.

Related literature

The title compound was first prepared in 1963, see: Schloegl et al. (1963 ▶). For an alternative synthesis using a Corey–Fuchs route, see: Luo et al. (2000 ▶). For the preparation of some other halo-vinyl ferrocenes, see: Naskar et al. (2000 ▶). For related functionalized ferrocenes, see: Clément et al. (2007a ▶) and for [2.2]paracyclophanes, see: Clément et al. (2007b ▶). For the parent compound, ethenylferrocene, see: McAdam et al. (2008 ▶).

Experimental

Crystal data

[Fe(C₅H₅)(C₇H₅Cl₂)]
M _r = 280.95
Monoclinic,
a = 14.340 (3) Å
b = 7.4370 (15) Å
c = 10.932 (2) Å
β = 108.48 (3)°
V = 1105.8 (4) Å³
Z = 4
Mo Kα radiation
μ = 1.81 mm⁻¹
T = 173 K
0.3 × 0.2 × 0.2 mm

Data collection

Bruker SMART APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 1999 ▶) T _min = 0.594, T _max = 0.694
3293 measured reflections
1908 independent reflections
1372 reflections with I > 2σ(I)
R _int = 0.05

Refinement

R[F ² > 2σ(F ²)] = 0.063
wR(F ²) = 0.174
S = 1.02
1908 reflections
136 parameters
H-atom parameters constrained
Δρ_max = 1.04 e Å⁻³
Δρ_min = −0.46 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT-Plus (Bruker, 1999 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS90 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809006102/zl2181sup1.cif

e-65-0m334-sup1.cif^{(16KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809006102/zl2181Isup2.hkl

e-65-0m334-Isup2.hkl^{(93.9KB, hkl)}

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

Acknowledgments

We are grateful to the French Ministere de la Recherche et Technologie for a PhD grant for SC. We also thank the Deutsche Forschungsgemeinschaft and the Fonds der Chemischen Industrie for financial support and the award of a scholarship (VHG).

supplementary crystallographic information

Comment

π-Conjugated ligands are widely applied in coordination chemistry, catalysis or polymer sciences. Among them, ethynylferrocene and its derivatives have gained special interest due to their use as building blocks for the synthesis of di- and polymetallic organometallic systems and advanced materials. In the context of our research into developing novel π-conjugated ligands such as functionalized ferrocenes (Clément et al., 2007a) and [2.2]paracyclophanes (Clément et al., 2007b) for potential applications in coordination chemistry, we have recently reported dehalobromation of (2,2-dibromovinyl)ferrocene and dibromovinyl[2.2]paracyclophane as a convenient route to the synthesis of the corresponding alkynes.

In order to take a closer glance on the influence of the halide leaving group in the starting materials {[Cl₂C=C(H)—Fc] versus [Br₂C=C(H)—Fc] (Fc = ferrocenyl)}, we prepared the title compound (2) according to a slightly modified literature procedure (Luo et al., 2000) under Corey-Fuchs conditions by treatment of ferrocenecarbaldehyde (1) with CCl₄ in the presence of zinc dust and triphenyl phosphane (Figure 3).

The molecular structure of 2 is shown in Figure 1. (2,2-Dichlorovinyl)ferrocene (2) crystallizes in the monoclinic crystal system, space group P2₁/c. The two cyclopentadienyl rings are almost eclipsed with a mean cyclopentadienyl twist angle of 6.17°. The dihedral angle between the Cp ring planes is 0.1 (5)°. The bond distance of the vinylic double bond between C(1) and C(2) of 1.321 (9) Å is almost identical with that of (2,2-dibromovinyl)ferrocene [1.318 (4) Å]. The alkenyl unit and the cyclopentadienido ring are fairly coplanar with an angle between the two best planes [(C1 C2 Cl1 Cl2) and (C3 C4 C5 C6 C7)] of only 10.6 (4)°. This value determined for 2 is comparable to that determined for (2,2-dibromovinyl)ferrocene (10.43°) (Clément et al., 2007a). Cl1 is involved in week C–H···Cl interactions (H8···Cl1ⁱ: 2.901 Å and C8–H8···Cl1ⁱ 166.8°; symmetry operator i: x,-y+1/2,+z-1/2). Overall, it seems that the influence of the halide on the molecular geometry is negligeable. In contrast to the parent compound ethenylferrocene (McAdam et al., 2008), where intermolecular C–H···π interactions are present in the solid state, no significant intermolecular interactions are observed in the packing of (2) (Figure 2).

Experimental

(2,2-Dichlorovinyl)ferrocene (2): Triphenyl phosphane (2.40 g, 8.5 mmol), CCl₄ (0.82 ml, 8.5 mmol) and zinc dust (0.55 g, 8.5 mmol) were placed in a Schlenk tube and 25 ml CH₂Cl₂ were slowly added. After stirring at room temperature for 28 h, ferrocenecarbaldehyde (1) (1.00 g, 4.24 mmol), dissolved in CH₂Cl₂ (10 ml), was added and stirring was continued for further 2 h. The reaction mixture was extracted with three 50 ml portions of pentane and CH₂Cl₂ was added when the reaction mixture became too viscous for further extractions. The extracts were filtered and evaporated under reduced pressure. The crude product was purified by column chromatography on silica gel with CH₂Cl₂/petroleum ether (1:1). Slow evaporation yielded red crystals of 2 (Yield: 91%). Characterization data have been previously described in the literature. (Luo et al., 2000)