1-(6-Ferrocenylhexyl)-1H-imidazole

The title compound, [Fe(C5H5)(C14H19N2)], is characterized by a ferrocenyl group separated from an imidazole functionality by a straight-chain hexyl unit. The two cyclopentadienyl rings of the ferrocenyl group show a marginal inward tilt of 2.17 (2)°. The imidazole unit, which is essentially planar (with a maximum deviation of 0.007 A for one of the N atoms) and tilted away from the ferrocenyl group [dihedral angle between the substituted ferrocenyl ring and the imidazole = 122.6 (1)°], is involved in intermolecular C—H⋯N interactions.

The title compound, [Fe(C 5 H 5 )(C 14 H 19 N 2 )], is characterized by a ferrocenyl group separated from an imidazole functionality by a straight-chain hexyl unit. The two cyclopentadienyl rings of the ferrocenyl group show a marginal inward tilt of 2.17 (2) . The imidazole unit, which is essentially planar (with a maximum deviation of 0.007 A for one of the N atoms) and tilted away from the ferrocenyl group [dihedral angle between the substituted ferrocenyl ring and the imidazole = 122.6 (1) ], is involved in intermolecular C-HÁ Á ÁN interactions.
The bond length between C19-N2 is 1.312 (4) Å which is a clear indication of a localized carbon-carbon double bond while those of C18-N2 = 1.379 (4) Å, C17-C18 = 1.361 (5) Å and C17-N1 = 1.365 (4) Å are longer and indicate delocalization of π electrons. This implies that aromaticity of the imidazole ring is also reduced. The torsion angles within the atoms of the ferrocenyl rings indicate that the rings are fairly planar. The two ferrocenyl rings also show a marginal tilt towards each other with an angle of 2.17°. The average bond distance of substituted ferrocenyl ring carbon atoms and the metal centre (Fe1) is found to be 2.039 (3) Å while that of the unsubstituted ferrocenyl ring is obtained as 2.027 (3) Å. A value of 114.0 (3)°i s observed for the N1-C16-C15 angle. The dihedral angle between the substituted ferrocenyl ring and the imidazole is found to be 122.6 (1)°. These observations confirm that the molecule is kinked and this, in turn, affects the molecular packing of the molecules which are held together by weak C-H···N interactions with a contact distance of about 2.583 Å.

Experimental
Imidazole(148 mg, 2.17 mmol) was added to acetone (2.0 cm 3 ) and the solution was stirred. Potassium hydroxide powder (128 mg, 2.27 mmol) was then introducedand allowed to dissolve, forming a homogenous solution. The solution was stirred for about 30 minutes and then 6-bromohexylferrocene (834 mg, 2.39 mmol) in acetone (1.0 cm 3 ) was introduced to the solution dropwise and allowed to stir for about 1 hour at room temperature. The solution was then filtered and concentrated.

Special details
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.