Methyl 2-[(ferrocenylcarbonyl)amino]- thiophene-3-carboxylate

# 2005 International Union of Crystallography Printed in Great Britain ± all rights reserved The title compound, [Fe(C5H5)(C12H10NO3S)], was synthesized from ferrocenecarboxylic acid and methyl 2-aminothiophene-3-carboxylate in modest yield. The substituted ring system is essentially planar through the amidothienylcarboxylate moiety, -(C5H4)CONH(C4H2S)CO2Me, with the amido unit at an angle of 3.60 (7) to the ®ve-atom thienyl group, which is oriented at an angle of 3.17 (7) to the ester moiety. The primary hydrogen bond is an intramolecular NÐ H O Ccarboxylate interaction [N O 2.727 (2) AÊ ], and the main intermolecular hydrogen bond involves a thienyl carboxylate and the carboxylate of a symmetry-related molecule [C O 3.443 (3) AÊ ].


Comment
Ferrocenyl derivatives have been the subject of much attention in coordination chemistry, given the important roles which they can play, encompassing both structural and electronic capabilities. The integration of ferrocene into new hybrid compounds has greatly expanded the potential and capabilities of new materials with a range of potential applications. Here, we report the synthesis and structure of the title ferrocenoylaminothienyl carboxylate derivative, (I).
Two views of (I) are depicted, with the atom-numbering scheme, in Figs. 1 and 2. Bond lengths and angles are unexceptional and in accord with anticipated values (Allen, 2002).
The primary hydrogen-bonding mode in (I) is an intramolecular hydrogen bond involving the amido NÐH with the carboxylate O C group, forming a ring with graph set S(6) (Bernstein et al., 1995) and directly in¯uencing the coplanarity of the atoms involved. Molecules of (I) assemble along the b axis through a CÐHÁ Á ÁO C interaction involving thienyl atom C5 and carboxylate atom O2, as indicated by C5Ð H5Á Á Á(O2 C2)# in Fig. 2 Allen, 2002) reveals a total of four derivatives (with coordinates). A related search for structures incorporating the ferrocenyl (as C 5 FeC 5 ) and thiophene groups (as C 4 S) yields 29 systems (the second scheme shows the structural fragments searched for in the Cambridge Structural Database) . In comparison, a search with ferrocene and pyridyl (as C 5 N) gives 317 structures, indicating the paucity of data for Sheteroaromatic donors as ligands in ferrocene chemistry when compared with typical heteroaromatic systems containing N donors such as pyridine (Allen, 2002).

Experimental
Methyl 2-N-(ferrocenoylamido)-thienyl-3-carboxylate, (I), was synthesized in low yield from the starting materials ferrocene carboxylic acid and methyl 2-aminothienyl-3-carboxylate using standard procedures. Full synthetic details, together with electrochemical studies, will be published in a full paper to follow this structure report.  A view of the primary interactions in the crystal structure of (I). Atoms labelled with the suf®xes #, * and & are at the symmetry positions (x, 1 + y, z), (x, y À 1, z) and (1 À x, 1 À y, 1 À z), respectively.

Figure 3
A stereoview of the hydrogen-bonded dimer generated by the CÐHÁ Á ÁS contact.
The H atom bound to N re®ned to an NÐH distance of 0.80 (2) A Ê . All H atoms bound to C atoms were treated as riding, with methyl CÐH = 0.98 A Ê and aromatic CÐH = 0.95 A Ê , and with U iso (H) = 1.5U eq (C) for methyl H atoms and 1.2U eq (C) for the remainder.