A new polymorph of 1-ferrocenyl-3-(3-nitro-anilino)propan-1-one

Abstract

Recrystallization of the title compound, [Fe(C 5H 5)(C 14H 13N 2O 3)], from a mixture of n-hexane and dichloro-methane gave the new polymorph, denoted (I), which crystallizes in the same space group (P1̄) as the previously reported structure, denoted (II). The Fe-C distances in (I) range from 2.015 (3) to 2.048 (2) Å and the average value of the C-C bond lengths in the two cyclo-penta-dienyl (Cp) rings is 1.403 (13) Å. As indicated by the smallest C-Cg1-Cg2-C torsion angle of 1.4° (Cg1 and Cg2 are the centroids of the two Cp rings), the orientation of the Cp rings in (I) is more eclipsed than in the case of (II), for which the value was 15.3°. Despite the pronounced conformational similarity between (I) and (II), the formation of self-complementary N-H⋯O hydrogen-bonded dimers represents the only structural motif common to the two polymorphs. In the extended structure, mol-ecules of (I) utilize C-H⋯O hydrogen bonds and, unlike (II), an extensive set of inter-molecular C-H⋯π inter-actions. Fingerprint plots based on Hirshfeld surfaces are used to compare the packing of the two polymorphs. © 2012 International Union of Crystallography.