N,N-Dibenzoyl­ferrocenecarboxamide

Mario Cetina; Veronika Kovač; Vladimir Rapić

doi:10.1107/S1600536811013754

. 2011 Apr 16;67(Pt 5):m610. doi: 10.1107/S1600536811013754

N,N-Dibenzoylferrocenecarboxamide

Mario Cetina ^a,^*, Veronika Kovač ^b,^*, Vladimir Rapić ^b

PMCID: PMC3089337 PMID: 21754327

Abstract

In the title compound, [Fe(C₅H₅)(C₂₀H₁₄NO₃)], the cyclopentadienyl rings deviate by 9.3 (2)° from an eclipsed conformation, defined by C—Cg ₁—Cg ₂—C pseudo-torsion angles ranging from 8.8 (1) to 9.85 (1)°. The coordination at the N atom is slightly pyramidal, as indicated by the angular sum around it of 352.6°. The amide group is inclined at 17.86 (9) and 27.27 (11)° with respect to the aromatic rings. In the crystal, molecules are linked by one C—H⋯O hydrogen bond and one C—H⋯π interaction into a two-dimensional framework parallel to the b axis.

Related literature

For background to ferrocene amides, see: Kohmoto et al. (2008 ▶); Masu et al. (2005 ▶, 2006 ▶); Moriuchi et al. (1995 ▶, 2000 ▶); Moriuchi & Hirao (2007 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For a description of the Cambridge Structural Database, see: Allen (2002 ▶).

Experimental

Crystal data

[Fe(C₅H₅)(C₂₀H₁₄NO₃)]
M _r = 437.26
Monoclinic,
a = 10.8699 (4) Å
b = 11.3387 (4) Å
c = 19.6264 (7) Å
β = 122.133 (2)°
V = 2048.42 (13) Å³
Z = 4
Mo Kα radiation
μ = 0.76 mm⁻¹
T = 295 K
0.56 × 0.53 × 0.43 mm

Data collection

Oxford Diffraction KM-4/Xcalibur diffractometer with a Sapphire3 detector
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2009 ▶) T _min = 0.910, T _max = 1.000
14704 measured reflections
5867 independent reflections
3472 reflections with I > 2σ(I)
R _int = 0.024

Refinement

R[F ² > 2σ(F ²)] = 0.032
wR(F ²) = 0.068
S = 0.93
5867 reflections
271 parameters
H-atom parameters constrained
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.24 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2009 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: WinGX (Farrugia, 1999 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811013754/im2277sup1.cif

e-67-0m610-sup1.cif^{(32.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811013754/im2277Isup2.hkl

e-67-0m610-Isup2.hkl^{(281.4KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

Cg2 is the centroid of the C6–C10 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C4—H4⋯O1ⁱ	0.93	2.56	3.241 (2)	131
C15—H15⋯Cg2ⁱⁱ	0.93	2.97	3.528 (2)	120

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

This research was supported by the Ministry of Science, Education and Sports of the Republic of Croatia (grant Nos. 058–1191344-3122 and 119–1193079-3069).

supplementary crystallographic information

Comment

Recently, aromatic foldamers with iminodicarbonyl linkers have been synthesized to investigate their structures in comparison with that of biopolymers, mostly proteins (Masu et al. 2005, 2006; Kohmoto et al. 2008). Also, considerable interest has been devoted to the synthesis of various imide based ferrocene derivatives in which the redox properties of transition metals permits their potential utilization as electrical materials and catalysts, e.g. ferrocenophanes (Moriuchi et al., 1995, 2000) or imide-bridged diferrocene for protonation-controlled regulation of electronic communication (Moriuchi & Hirao, 2007). Considering these previous studies we decided to prepare some new ferrocene containing imides notably due to investigation of their structure. During the synthesis of model substances as a part of our current research on ferrocene foldamers with iminodicarbonyl linkers we have isolated the title compound 1 and its structure is described in this paper.

A survay of Cambridge Structural Database (Allen, 2002) revealed that 1 (Fig. 1) is the first structure with a N–(C=O)₃ fragment linked to the ferrocenyl moiety. N1 is pyramidal and is displaced by 0.228 (1)Å out of the plane defined by atoms C11/C12/C19. Because of pyramidality, the angular sum around N1 is 352.6°. A somehow close C14–H14···N1 interaction of 2.55 Å seems to be indicative for a intramolecular hydrogen bond forming a five-membered ring that could be described by graph set descriptors as S(5) (Bernstein et al., 1995). On the other hand, the C14–H14···N1 angle is very small (101°) and there is no difference in chemical shifts for protons at C14 and C18 in the ¹H NMR spectrum (7.91 p.p.m., doublet, for 4 protons of the C14, C18, C21, C25), therefore indicating the absence of an intramolecular hydrogen bond at least in solution.

The C11=O1 carbonyl group and C1–C5 ring form an extended π-conjugated system, and therefore C1–C11 bond is shortened. The coplanar arrangement of a carbonyl group attached to the cyclopetadienyl (Cp) ring should allow maximum interaction of two π-systems. The C11=O1 bond is twisted out of the plane of the C1–C5 ring for 18.81 (11)°. The Cp rings deviate 9.3 (2)° from an eclipsed conformation. The value of the C–Cg₁–Cg₂–C pseudo-torsion angles, defined by joining two eclipsing Cp carbon atoms through the ring centroids range from 8.8 (1) to 9.8 (1)°. The Cp rings are almost parallel, with a dihedral angle between the mean planes of the rings of 1.84 (11)°. The amide groups do not lie in the plane of the attached aromatic rings. Thus, the plane of the C13/C12/O2/N1 atoms is inclined to the C13–C18 phenyl ring for 17.86 (9)°, and the plane of the C19/C20/O3/N1 atoms is inclined to the C20–C25 phenyl ring for even 27.27 (11)°. Two phenyl rings are perpendicular with respect to the C1–C5 ring. The corresponding dihedral angles are 85.36 (9) and 88.17 (10)° for C13–C18 and C20–C25 rings, respectively.

Molecules of 1 are self-assembled by C4–H4···O1 hydrogen bonds (Fig. 2; Table 1) into C(6) (Bernstein et al., 1995) spirals parallel to the b axis. Hydrogen-bonded chains are further weakly linked by one C–H···π interaction, C15–H15···Cg2, also parallel to the b axis forming a two-dimensional framework.

Experimental

To a suspension of hexane-washed sodium hydride (60% NaH in mineral oil, 78 mg; 2.027 mmol) in dry tetrahydrofuran (5 ml), a solution of ferrocene amide (188 mg; 0.821 mmol) in dry tetrahydrofuran (5 ml) was dropped and the mixture was heated at reflux for 2 h. After cooling benzoyl chloride (0.13 ml; 1.126 mmol) was added and the reaction mixture was stirred at room temperature overnight. After removing the solvent the remaining residue was dissolved in dichloromethane, washed with water and brine, dried over anhydrous sodium sulfate and evaporated. TLC purification gave 111 mg (41%) orange crystals of N-benzoylferrocenecarboxamide 2 and 76 mg (21%) red crystals of the title compound 1. A single-crystal of 1 was grown by slow evaporation from a saturated dichloromethane solution.