Ethyl 3-ferrocenyl-1-(pyridin-2-ylmethyl)-1H-pyrazole-5-carboxylate

The title compound, [Fe(C5H5)(C17H16N3O2)], crystallizes with an essentially eclipsed conformation of the cyclopentadienyl (Cp) rings. The unsubstituted ring is disordered over two positions with the major component being present 90 (1)% of the time. The substituted Cp ring, the pyrazole ring and three atoms of the ethoxycarbonyl group form a conjugated π-system. These 13 atoms are coplanar within 0.09 Å.

The title compound, [Fe(C 5 H 5 )(C 17 H 16 N 3 O 2 )], crystallizes with an essentially eclipsed conformation of the cyclopentadienyl (Cp) rings. The unsubstituted ring is disordered over two positions with the major component being present 90 (1)% of the time. The substituted Cp ring, the pyrazole ring and three atoms of the ethoxycarbonyl group form a conjugated -system. These 13 atoms are coplanar within 0.09 Å .

Experimental
Crystal data [Fe(C 5 et al., 2007;Ojwach et al.;2009). Herein we report the structure of the title compound (I).
The crystal structure of (I) was determined at room temperature because the crystals cracked upon flash-and slow-cooling to 100 K. The structural parameters of (I) are typical as confirmed by a Mogul geometry check (Bruno et al., 2002). is 9.91 (6)°; the torsion angle between the pyrazolyl ligand and the plane defined by atoms C14,O1,O2 is 3.66 (9)°; thus these three fragments form a conjugated system.
Yield: (0.030 g, 21%). Single crystals were obtained by slow evaporation of a solution of (I) in dichloromethane-toluene (3:1) solvent system at room temperature.

Refinement
All H-atoms were placed in idealized locations and refined as riding with appropriate thermal displacement coefficients U iso (H) = 1.2 times U eq (bearing atom) for aromatic and methylene H atoms, and 1.5 times U eq (bearing atom) for the methyl supplementary materials sup-2 H atoms.. The C-H distances were fixed at 0.93, 0.96, and 0.97 Å for aromatic, methyl, and methylene H atoms respectively.
The C6a-C10a ring was refined with an idealized geometry. The thermal dsiplacement parameters for atoms C6a-C10a were contrained to be identical to those of atoms C6-C10, respectively. Fig. 1. Molecular structure of (I) (Brandenburg, 1999). Thermal ellipsoids are shown at the 50% probability level. All hydrogen atoms were omitted for clarity.