N′-Ferrocenyl-2-hydroxybenzohydrazide

The title complex, [Fe(C5H5)(C13H11N2O3)], was prepared via self-assembly using ferrocenyl hydrazide and ethyl salicylate. The compound is potentially a tridentate ferrocene-based ligand. The conformation of the molecule allows the formation of an intramolecular N—H⋯O hydrogen bond involving the hydroxyl group. The CONHNHCO unit and the rings bonded to it are nearly coplanar. The crystal structure is stabilized by intermolecular O—H⋯O(carbonyl) and N—H⋯O(carbonyl) hydrogen bonds.

The title complex, [Fe(C 5 H 5 )(C 13 H 11 N 2 O 3 )], was prepared via self-assembly using ferrocenyl hydrazide and ethyl salicylate. The compound is potentially a tridentate ferrocene-based ligand. The conformation of the molecule allows the formation of an intramolecular N-HÁ Á ÁO hydrogen bond involving the hydroxyl group. The CONHNHCO unit and the rings bonded to it are nearly coplanar. The crystal structure is stabilized by intermolecular O-HÁ Á ÁO(carbonyl) and N-HÁ Á ÁO(carbonyl) hydrogen bonds.

Comment
The synthesis, isolation and characterization of ferrocene in 1951 marked an important milestone in the evolution of modern organometallic chemistry. Potential applications in material sciences, such as molecular sensors (Beer, 1992;Beer & Smith, 1997), molecular magnetic materials (Miller & Epstein, 1994), and nonlinear optical materials (Nguyen et al., 1999;Long, 1995) attracted much attention. We report here the crystal structure of the title compound, (I), a new ferrocene-based complex (Fig. 1).
In the crystal, molecules are connected by intermolecular hydrogen bonds involving carbonyl O atoms O2 and O3 as acceptor and N-H or O-H groups as donors.

Experimental
All reagents were commercially available and of analytical grade. Ferrocenyl hydrazide (1.22 g, 5 mmol) and ethyl salicylate (0.83 g, 5 mmol) were mixed in ethanol and refluxed for 7 h. The resulting red solid was filtered, washed with ethanol and dried under reduced pressure. Anal. Calc. for C 18 H 16 FeN 2 O 3 : C 59.37, H 4.43, N 7.69%. Found: C 59.48, H 4.31, N 7.52%.

Refinement
H atoms bonded to C atoms were positioned geometrically and refined as riding on their carrier atoms, with C-H bond lengths fixed to 0.93 (benzene ring) or 0.98 Å (Cp rings), and U iso (H) = 1.2U eq (carrier C). H atoms bonded to heteroatoms N1, N2 and O3 were located in a difference map and were freely refined as isotropic atoms, with restricted bond lengths: Fig. 1. The molecular structure of (I) with displacement ellipsoids drawn at the 50% probability level.