(E)-1-Ferrocenyl-3-(2-furyl)prop-2-en-1-one

The title compound, [Fe(C5H5)(C12H9O2)], exhibits an E configuration. In the ferrocene unit, the two cyclopentadienyl rings are almost parallel [dihedral angle = 0.76 (12)°] and the C atoms are in an eclipsed conformation. An intramolecular C—H⋯O hydrogen bond generates an S(5) ring. In the crystal, the molecules are linking into zigzag chains via two C—H⋯O hydrogen-bonding interactions along the c axis and neighbouring chains are stabilized by electrostatic interaction forces.

The title compound, [Fe(C 5 H 5 )(C 12 H 9 O 2 )], exhibits an E configuration. In the ferrocene unit, the two cyclopentadienyl rings are almost parallel [dihedral angle = 0.76 (12) ] and the C atoms are in an eclipsed conformation. An intramolecular C-HÁ Á ÁO hydrogen bond generates an S(5) ring. In the crystal, the molecules are linking into zigzag chains via two C-HÁ Á ÁO hydrogen-bonding interactions along the c axis and neighbouring chains are stabilized by electrostatic interaction forces.

Related literature
For the biological activity of chalcones and chalcone derivatives, see: Liu et al. (2003). For the ability of some chalcones to block voltage-dependent potassium channels, see: Yarishkin et al. (2008). Replacement of the aromatic group of penicillins and cephalosporins by a ferrocenyl group could improve their antibiotic activity, see: Edwards et al. (1975). For our ongoing research in this area, see: Shi et al. (2004); Liu, Liu et al. (2008). For the synthesis, see: Huang et al. (1998). For a related structure, see: Liu, Ye et al. (2008) For graph-set notations of ring systems, see: Bernstein et al. (1995). For related literature, see: Zhai et al. (1999).

Experimental
Crystal data [Fe(C 5 -H. Liu and R. Guo

Comment
Chalcone and its derivatives, as a natural produce, have shown strong antibacterial, antifungal, antitumor and anti-inflammatory properties (Liu et al., 2003). Some chalcones demonstrated the ability to block voltage-dependent potassium channels (Yarishkin et al., 2008). It has been demonstrated that the replacement of the aromatic group by the ferrocenyl moiety in penicillins and cephalosporins could improve their antibiotic activity (Edwards et al., 1975). As on going research (Liu & Liu et al., 2008;Shi et al., 2004), we report herein the structure of the title compound.
The molecule of the title compound exists in the most stable configuration of (E)-isomer ( Fig. 1). All of the C and O atoms are sp 2 -hybrid resulting in two large conjugated systems: one is formed by C1-C5 atoms and the other by the rest of the atoms. There is an intra-molecular hydrogen-bond C13-H13···O1 resulting in a five membered ring, S(5) in graph set notation (Bernstein et al., 1995). The atoms O1/C11/C12/C13 are essentially planar and their mean-plane lies at 3.10 (14) and 16.35 (13)  In the crystal structure, inter-molecular hydrogen-bonds of the type C-H···O, along the c axis, generate a R 2 1 (7) motif (Bernstein et al., 1995), linking the adjacent molecules into a zig-zag chain (Fig. 2, Tab. 1). Further more, the chain and its neighboring inverse parallel chains are stablilized by electrostatic interaction forces.

Experimental
The title compound was synthesized according to the literature procedure (Huang et al., 1998). An aqueous solution of potassium hydroxide (5%, 5 ml) was added slowly with stirring to a mixture of 2-furanylaldehyde (4.0 g, 0.043 mol) and acetoylferrocene (0.98 g, 0.043 mol) in ethanol (20 ml) in ice bath. The resulting mixture was stirred at room temperature for 4 h. The dark-red precipitated solid was filtered off, washed with water, dried and recrystallized from 95% ethanol (yield, 83%; M.P. 429.5-430.8 K. Crystals of (I) suitable for X-ray diffraction were obtained by slow evaporation of a solution of the solid in dichloromethane/ ether (4:1 v/v) at room temperature over a period of 6 d.

Refinement
After their location in a difference map, all H atoms were fixed geometrically at ideal positions and allowed to ride on the parent C atoms, with C-H = 0.93 Å and U iso (H) = 1.2U eq (C). An absolute structure was determined using anomalous dispersion effects employing 1353 Friedel pairs which were not merged. Fig. 1. The molecular structure of the title compound, showing 50% probability ellipsoids. The C-H···O intra-molecular hydrogen bond is shown as dashed lines.  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.

sup-2 Figures
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.