(E)-1-Ferrocenyl-3-[2-(2-hydroxyethoxy)phenyl]prop-2-en-1-one

In the title compound, [Fe(C5H5)(C16H15O3)], the cyclopentadienyl rings are in an eclipsed conformation and the benzene ring makes dihedral angles of 10.84 (9) and 12.35 (9)°, respectively, with the substituted and unsubstituted cyclopentadienyl rings. In the crystal, molecules form inversion dimers through pairs of O—H⋯O hydrogen bonds. Weak C—H⋯O hydrogen bonds are observed between the dimers.

In the title compound, [Fe(C 5 H 5 )(C 16 H 15 O 3 )], the cyclopentadienyl rings are in an eclipsed conformation and the benzene ring makes dihedral angles of 10.84 (9) and 12.35 (9) , respectively, with the substituted and unsubstituted cyclopentadienyl rings. In the crystal, molecules form inversion dimers through pairs of O-HÁ Á ÁO hydrogen bonds. Weak C-HÁ Á ÁO hydrogen bonds are observed between the dimers.

Raghunathan Comment
Ferrocenyl derivatives exhibit antitumor (Jaouen et al., 2004), antibacterial (Fouda et al., 2007), antifungal and antimalarial (Biot et al., 2004) activities. It was proved that the replacement of the aromatic group by the ferrocenyl moiety in penicillins and cephalosporins could improve their antibiotic activity (Edwards et al., 1975). Against this background, the title compound was chosen for X-ray structure analysis (Fig. 1).
In the title compound, the benzene ring makes dihedral angles of 10.84 (9) and 12.35 (9)°, respectively, with the substituted and unsubstituted cyclopentadienyl (Cp) rings of the ferrocenyl unit. In ferrocenyl unit, the two Cp rings are planar and are parallel to each other with a dihedral angle of 1.56 (9)° between them. The Fe atom lies in the middle of the two planes of Cp rings. The distances of the Fe1 atom from the centroids of the substituted and unsubstituted cyclopentadienyl rings are 1.646 (10) and 1.650 (12) Å, respectively. The Cg1-Fe1-Cg2 angle is 179.21 (5)°, where Cg1 and Cg2 are the centroids of substituted and unsubstituted Cp rings, respectively. The C-C bond distances in the Cp rings range from 1.381 (4) to 1.429 (3) Å, while Fe-C bond lengths range between 2.023 (1) and 2.058 (2) Å and all of which are as expected (Zora et al., 2006). The torsion angles O1-C1-C2-O2 and O3-C11-C12-C13 [56.6 (3)° and -12.5 (3)°, respectively] indicate the bent conformation of the molecule. The crystal packing features O-H···O and weak C-H···O hydrogen bonds (Table 1).

Experimental
A solution of acetylferrocene (3 g, 1.0 mmol) in ethanol (20 ml) was cooled to 0 °C and a solution of sodium hydroxide (0.48 g, 12.0 mmol) in water (2 ml) was added drop wise under vigorous stirring for 10 minutes. To the above mixture 2-(2-hydroxyethoxy)benzaldehyde (2.0 g, 12.0 mmol) in ethanol (10 ml) was added and stirred for 3 h in room temperature. Then, the reaction mixture was quenched in crushed ice and the solid obtained was filtered using Buchner funnel. The crude product was then subjected to column chromatography using hexane/ethyl acetate mixture (7:3) as eluent.

Refinement
Hydrogen atoms were positioned geometrically and allowed to ride on their parent atoms, with C-H = 0.93-0.97 Å and O-H = 0.88 Å, and with U iso (H) = 1.5U eq (C) for methyl H atoms, 1.2U eq (C) for other C-bound H atoms and 1.5U eq (O) for the hydroxyl H atom.

Figure 1
The molecular structure of the title compound, showing the atom-numbering scheme and displacement ellipsoids drawn at the 20% probability level.

(E)-1-Ferrocenyl-3-[2-(2-hydroxyethoxy)phenyl]prop-2-en-1-one
where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.29 e Å −3 Δρ min = −0.28 e Å −3 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.