1-Acetyl-3-ferrocenyl-5-(2-nitrophenyl)-2-pyrazoline

In the title compound, [Fe(C5H5)(C16H14N3O3)], the pyrazoline ring and the substituted cyclopentadienyl ring are nearly coplanar, with a dihedral angle of 8.17 (2)°, while the nitro-substituted benzene ring is twisted out of the pyrazoline ring plane by 70.76 (1)°. The molecules in the crystal structure are held together by three intermolecular C—H⋯O hydrogen bonds. There is also an intramolecular C—H⋯N hydrogen bond. The H atoms of the methyl group are disordered equally over two positions.

Among them ferrocenyl compounds display interesting antibacterial (Fouda et al., 2007), antitumor (Jaouen et al., 2004), antimalarial andantifungal (Biot et al., 2004) activities. Therefore, incorporation of a ferrocene fragment into a heterocyclic ring may enhance their biological activities or generate new medicinal properties (Fang et al., 2003). As a part of an ongoing investigation of the chemistry of ferrocenyl pyrazolines, the title compound was synthesized and its crystal structure was determined.
The molecular structure of the title compound is shown in Fig. 1. The puckering parameters (Cremer & Pople, 1975) are q 2 =0.037 (3)Å and φ=43.3 (8)° for the pyrazoline ring, q 2 =0.008 (3)Å and φ=156.3 (2)° for the substituted cyclopentadienyl (Cp) ring and q 2 =0.004 (3)Å and φ=69.6 (5)° for the unsubstituted Cp ring. The dihedral angle of 8.17 (2) The Fe-Cg s and Fe-Cg as distances are 1.6398 (14) and 1.6544 (14) Å, respectively, and the Cg s -Fe-Cg as angle is 177.78 (7)°, where Cg s and Cg as are the centroids of the substituted and unsubstituted Cp rings. The small dihedral angle of 3.68 (2)° between the unsubstituted and substituted Cp rings indicates that the two Cp rings are parallel to each other (Shi et al., 2006a). The C12-Cg s -Cg as -C20 torsion angle of 3.71 (2)° indicates that the two Cp rings of the ferrocenyl group is nearly in an eclipsed conformation, as was previously observed in a ferrocene-containing compound (Zora et al., 2008).
The pyrazoline ring and the nitro substituted phenyl group make a dihedral angle of 70.76 (1)°. The dihedral angle between the nitro plane and pheny ring is 18.30 (5)°. The dihedral angles between the phenyl ring and the substituted and unsubstituted Cp planes are 76.16 (1) and 76.12 (1)°, respectively. The molecules in crystal are held together by three intermolecular C-H···O hydrogen bonds (Table 2; Fig. 2). There is one intramolecular C-H···N hydrogen bond.
supplementary materials sup-2 Experimental A mixture of 1-ferrocenyl-3-(2-nitrophenyl)-2-propenone (0.09 g, 0.24 mmol), 80% hydrazine hydrate (0.264 g, 5.28 mmol) and glacial acetic acid (10 ml) was refluxed under nitrogen atmosphere for 5 h. TLC indicated the formation of the reaction product. It was poured into ice-water to give dark orange solid. The participate was separated by filtration and washed with water. The solid product was dried at room temperature. Single crystals of the title compound suitable for X-ray measurements were obtained by recrystallization from methanol at room temperature (yield 50.5%; m.p. 425-426 K). IR

Refinement
H atoms were positioned geometrically and refined as riding atoms, with C-H = 0.93 (aromatic), 0.98 (CH) and 0.97 Å (CH 2 ) and with U iso (H) = 1.2U eq (C). H atoms of the methyl group (C11) show rotational disorder from a difference Fourier map. These H atoms were refined as riding atoms, with C-H = 0.96 Å and U iso (H) = 1.5U eq (C). Fig. 1. The molecular structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level.