Methyl 2-(4-ferrocenylbenzamido)thiophene-3-carboxylate and ethyl 2-(4-ferrocenylbenzamido)-1,3-thiazole-4-acetate, a unique ferrocene derivative containing a thiazole moiety

Abstract

The conformations and hydrogen bonding in the thiophene and thiazole title compounds, [Fe(C5H5)(C20H14NO3S)], (I), and [Fe(C5H5)(C19H17N2O3S)], (II), are discussed. The sequence (C5H4)-(C6H4)-(CONH)-(C4H2S)-(CO2Me) of rings and moieties in (I) is close to being planar; all consecutive interplanar angles are less than 10 degrees . An intramolecular N-H...O=C(ester) hydrogen bond [graph set S6, N...O = 2.768 (2) A and N-H...O = 134 (2) degrees ] effects the molecular planarity, and aggregation occurs via hydrogen-bonded chains formed from intermolecular C(ar)-H...O=C(ester/amide) interactions along [010], with C...O distances ranging from 3.401 (3) to 3.577 (2) A. The thiazole system in (II) crystallizes with two molecules in the asymmetric unit; these differ in the conformation along their long molecular axes; for example, the interplanar angle between the phenylene (C6H4) and thiazole (C3NS) rings is 8.1 (2) degrees in one molecule and 27.66 (14) degrees in the other. Intermolecular N-H...O=C(ester) hydrogen bonds [N...O = 2.972 (4) and 2.971 (3) A], each augmented by a C(phenylene)-H...O=C(ester) interaction [3.184 (5) and 3.395 (4) A], form motifs with graph set R2(1)(7) and generate chains along [100]. The amide C=O groups do not participate in hydrogen bonding. Compound (II) is the first reported ferrocenyl-containing thiazole structure.