1-Ferrocenylmethyl-1H-imidazole

In the title compound, [Fe(C5H5)(C9H9N2)], the distances of the Fe atom from the centroids of the unsubstituted and the substituted cyclopentadienyl (cp) rings are 1.639 (1) and 1.647 (1) Å, respectively. The ferrocenyl unit deviates from an eclipsed geometry with tilted cp rings; the interplanar angle between the cp and imidazole rings is 114.11 (4)°.

In the title compound, [Fe(C 5 H 5 )(C 9 H 9 N 2 )], the distances of the Fe atom from the centroids of the unsubstituted and the substituted cyclopentadienyl (cp) rings are 1.639 (1) and 1.647 (1) Å , respectively. The ferrocenyl unit deviates from an eclipsed geometry with tilted cp rings; the interplanar angle between the cp and imidazole rings is 114.11 (4) .

Experimental
Crystal data [Fe(C 5

Comment
The synthesis of arylimidazole compounds is of importance because of their significance in pharmaceutical (Ohmori et al. 1996), biological (Cozzi et al. 1993) and the synthesis of fine chemicals (Lee & Nolan, 2000;Herrmann & Köcher, 1997).
Ferrocenyl compounds with an N-heterocycle group such as ferrocenylmethyl benzimidazole have been studied and found to exhibit anticancer activity (Snegur et al. 2004). The ferrocenylimidazolium salts have also found uses in catalysis as precursors for the synthesis of N-heterocyclic carbenes (César et al., 2004;Broggini & Togni, 2002).
In the title compound (I, Fig. 1), the distance of the Fe atom from the centroids of the substituted (C1-C5) and the unsubstituted (C6-C10) cyclopentadienyl rings are 1.639 (1) and 1.647 (1) Å respectively, indicating a slight shotening of the substituted cp-Fe bond length due to the substitution of the imidazole unit. The plane of the imidazole ring in (I) is tilted at an angle of 114.11 (4)° away from the plane of the C1-C5 cp ring. The strain on the substituted ring results in a corresponding tilt of 3.87 (2)° between the planes of the two cp rings. The cp rings also deviate significantly from an eclipsed conformation with torsion angles ranging from 19.98 (2)-24.90 (2)°. This could be due to the fact that the C1-C5 cp ring twists in order to accommodate the bulky imidazole unit, hence putting it out of coplanarity with the unsubstituted C10-C14 cp ring.

Experimental
A mixture of equimolar amounts of ferrocenylmethanol (501 mg, 2.34 mmol) and N,N'-carbonyldiimidazole (379 mg, 2.34 mmol) in anhydrous dichloromethane was heated under reflux for 1 h. The resulting mass was cooled and then diethyl ether (50 cm 3 ) was added and the resultant solution was allowed to stir for 3 minutes before being transferred to a separating funnel. The reaction mixture was then flushed with phosphoric acid (2 x 50 cm 3 ). The aqueous phase fractions were then combined and the pH of the solution was adjusted to 5 using dilute sodium hydroxide. The aqueous solution was then extracted using dichloromethane (3 x 50 cm 3 ). The dichloromethane extracts were combined, dried over anhydrous sodium sulfate, filtered and the solvent was removed in vacuo. The resulting product was subjected to column chromatography on a column of silica gel. Diethyl either was used to elute unreacted starting material and a mixture of ethyl acetate and methanol provided the title compound 1-(Ferrocenymethyl)-1H-imidazole. Yield: (398 mg, 64%); Yellow crystals mp 66-67 °C; IR ν max (KBr cm -1 )3095, 1644,1511,1463,1439,1391,1336,1322,1279,1238,1221,1104,1079,1040,1027,1002,916,811,744,752,697,662,503 All H atoms attached to C atoms were fixed geometrically and treated as riding with C-H = 0.95 Å and U iso (H) = 1.2U eq (C). Fig. 1. Molecular structure of the title complex with the atom labelling scheme. Ellipsoids are drawn at the 50% probability level.