Ferrocene-1-carbaldehyde 4-ethylthiosemicarbazone

The asymmetric unit of title compound, [Fe(C5H5)(C9H12N3S)], contains two crystallographically independent molecules, A and B. The two cyclopentadienyl (Cp) rings are parallel to each other in both molecules, forming dihedral angles of 2.3 (3) and 1.0 (3)°, respectively, and adopt an eclipsed conformation. The mean plane of the semicarbazone group is twisted slightly away from the attached Cp ring in both molecules, the dihedral angles between the mean plane and the Cp ring being 15.3 (2) and 10.8 (2)°. The ethyl group in molecule A is coplanar with the mean plane of the semicarbazone group [C—N—C—C torsion angle = −175.2 (4)°], whereas it is nearly perpendicular in molecule B [C—N—C—C torsion angle = 84.8 (6)°]. In the crystal structure, intermolecular N—H⋯S hydrogen bonds link the molecules into dimers. These dimers are further linked into chains via intermolecular C—H⋯S hydrogen bonds. The crystal studied was a non-merohedral twin with a refined ratio of the twin components of 0.265 (2):0.735 (2).

The asymmetric unit of title compound, [Fe(C 5 H 5 )-(C 9 H 12 N 3 S)], contains two crystallographically independent molecules, A and B. The two cyclopentadienyl (Cp) rings are parallel to each other in both molecules, forming dihedral angles of 2.3 (3) and 1.0 (3) , respectively, and adopt an eclipsed conformation. The mean plane of the semicarbazone group is twisted slightly away from the attached Cp ring in both molecules, the dihedral angles between the mean plane and the Cp ring being 15.3 (2) and 10.8 (2) . The ethyl group in molecule A is coplanar with the mean plane of the semicarbazone group [C-N-C-C torsion angle = À175.2 (4) ], whereas it is nearly perpendicular in molecule B [C-N-C-C torsion angle = 84.8 (6) ]. In the crystal structure, intermolecular N-HÁ Á ÁS hydrogen bonds link the molecules into dimers. These dimers are further linked into chains via intermolecular C-HÁ Á ÁS hydrogen bonds. The crystal studied was a non-merohedral twin with a refined ratio of the twin components of 0.265 (2):0.735 (2).

Related literature
For related structures, see: Vikneswaran et al. (2009Vikneswaran et al. ( , 2010. For the preparation of the title compound, see: Casas et al. (2004). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986).

Experimental
Formylferrocene 4-ethylthiosemicarbazone was prepared as described by Casas et al. (2004). The single crystals were grown from a CH 2 Cl 2 /n-CH 6 H 14 (1:1 v/v) solution at room temperature in the dark.

Refinement
N bound H-atoms were located from difference Fourier map and refined freely. The rest of H-atoms were placed in calculated positions, with C-H = 0.93-0.98 Å and refined using a riding model, with U iso (H) = 1.2 or 1.5U eq (C). Rotating-group model were applied for methyl group. The highest residual density peak is located 0.88 Å from atom Fe1B and the deepest hole is located 1.32 Å from atom C12B. The crystal studied is a non-merohedral twin with the refined ratio of twin components of 0.265 (2):0.735 (2).

Special details
Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 Rfactors(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.