2-[(Ferrocen-1-yl)(hydroxy)methyl]prop-2-enenitrile

In the title ferrocene derivative, [Fe(C5H5)(C9H8NO)], the dihedral angle between the enenitrile group and the substituted cyclopentadienyl ring is 71.2 (1)°. The cyclopentadienyl rings of the ferrocene moiety are arranged in an eclipsed conformation. The hydroxy group, and the corresponding methine H atom, are disordered over two sets of sites with site-occupancy factors of 0.744 (4) and 0.256 (4). An intramolecular C—H⋯O close contact is observed. In the crystal, O—H⋯N hydrogen bonds form a C(6) chain along [100].

In the title ferrocene derivative, [Fe(C 5 H 5 )(C 9 H 8 NO)], the dihedral angle between the enenitrile group and the substituted cyclopentadienyl ring is 71.2 (1) . The cyclopentadienyl rings of the ferrocene moiety are arranged in an eclipsed conformation. The hydroxy group, and the corresponding methine H atom, are disordered over two sets of sites with site-occupancy factors of 0.744 (4) and 0.256 (4). An intramolecular C-HÁ Á ÁO close contact is observed. In the crystal, O-HÁ Á ÁN hydrogen bonds form a C(6) chain along [100].

Comment
Ferrocene derivatives posses antimicrobial (Li et al., 2013), antibacterial (Skiba et al., 2012) and antitumor (Karolyi et al., 2012) activities. In view of these important properties, we have undertaken the crystal structure determination of the title compound, and the results are presented here.
The X-ray study confirmed the molecular structure and atomic connectivity of the title compound, as illustrated in Fig.   1. The geometry of the ferrocenyl group is comparable with the related literature (Leka et al., 2012a,b). The cyclopentadienyl rings are almost parallel forming a dihedral angle between the mean planes of the rings of 0.18 (1)°, while the distances of Fe1 to Cg1 (C1-C5) and Cg2 (C6-C10) centroids are 1.643 (1) and 1.637 (1) Å, respectively. The bond length C13-N1 of 1.124 (3) Å confirms the triple bond character. The enenitrile group is almost perpendicular to the cyclopentadienyl ring, oriented with a dihedral angle of 71.2 (1)° with respect to the mean plane of the ring. The hydroxy group, and the corresponding methine H atom, are disordered over two orientations, with site-occupancy factors of 0.744 (4) and 0.256 (4).
In addition to the van der Waals interactions, the molecular structure is influenced by intramolecular C-H···O interactions. In the molecular packing, O-H···N hydrogen bonds form a C(6) chain motif along the ac plane of the unit cell ( Fig. 2).

Experimental
A mixture of ferrocenecarboxaldehyde (10 mmol), acrylonitrile (12 mmol) and 1,4-diazabicyclo[2.2.2]octance (20 mol%) was stirred at room temperature for about 30 days. Silica gel was added to the reaction mixure and the product was isolated by using hexane/ethylacetate (3:1) as eluent. Single crystals of the title compound were obtained by slow evaporation of a methanol solution of the title compound at room temperature.

Refinement
H atoms were placed in idealized positions and allowed to ride on their parent atoms, with C-H distances in the range 0.93-0.98 Å, and U iso (H) = 1.2U eq (C) for H atoms. The atoms H11 and O1 are disordered over two positions: the major component exhibits a refined site-occupancy factor of 0.744 (4). The bond distances C11-O1 and C11-O1′ were restrained with a DFIX command (Sheldrick, 2008) Å while the anisotropic thermal parameters of O1′ and H11′ were set to those of O1 and H11 [EADP instruction; Sheldrick, 2008)].

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Occ. (