2-Ferrocenyl-N-(2-ferrocenylbenzo­yl)-N-(4-methyl-2-pyrid­yl)benzamide

John F Gallagher; Steven Alley; Alan J Lough

doi:10.1107/S1600536809006278

. 2009 Feb 28;65(Pt 3):m332–m333. doi: 10.1107/S1600536809006278

2-Ferrocenyl-N-(2-ferrocenylbenzoyl)-N-(4-methyl-2-pyridyl)benzamide

John F Gallagher ^a,^*, Steven Alley ^a, Alan J Lough ^b,^‡

PMCID: PMC2968647 PMID: 21582102

Abstract

The title compound, [Fe₂(C₅H₅)₂(C₃₀H₂₂N₂O₂)], a 2:1 product of the reaction of 2-ferrocenylbenzoic acid and 2-amino-4-methylpyridine, forms a twisted molecular structure in the solid state due to steric effects from the two benzene rings ortho-substituted with ferrocenyl and carbonyl-derived groups. A short intramolecular C—H⋯π interaction is observed involving a substituted η⁵-C₅H₄ ring and an ortho H atom of the benzene ring on the opposite side of the molecule. In the crystal structure, there are no classical hydrogen bonds: interactions comprise a short C₆—H⋯π(C₆) interaction involving substituted benzene rings and two C—H⋯O=C interactions per molecule.

Related literature

For background information, see: Gallagher et al. (2008 ▶, 2009a ▶,b ▶). For the parent compound, 2-(dibenzoylamino)pyridine, see: Weng et al. (2006 ▶). For a related ferrocene derivative, see: Moriuchi & Hirao (2007 ▶). For related structures, see: Akinboye et al. (2009a ▶,b ▶). For a description of the Cambridge Structural Database, see: Allen (2002 ▶).

Experimental

Crystal data

[Fe₂(C₅H₅)₂(C₃₀H₂₂N₂O₂)]
M _r = 684.38
Triclinic,
a = 12.0861 (7) Å
b = 12.4935 (8) Å
c = 12.5028 (8) Å
α = 65.159 (3)°
β = 62.696 (3)°
γ = 81.580 (3)°
V = 1519.83 (16) Å³
Z = 2
Mo Kα radiation
μ = 1.00 mm⁻¹
T = 150 K
0.22 × 0.22 × 0.14 mm

Data collection

Nonius KappaCCD diffractometer
Absorption correction: multi-scan (SORTAV; Blessing, 1995 ▶) T _min = 0.811, T _max = 0.873
10819 measured reflections
6865 independent reflections
3530 reflections with I > 2σ(I)
R _int = 0.107

Refinement

R[F ² > 2σ(F ²)] = 0.060
wR(F ²) = 0.154
S = 0.95
6865 reflections
417 parameters
H-atom parameters constrained
Δρ_max = 0.77 e Å⁻³
Δρ_min = −0.87 e Å⁻³

Data collection: KappaCCD Server Software (Nonius, 1997 ▶); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997 ▶); data reduction: DENZO-SMN; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶) and SORTX (McArdle, 1995 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXL97 and PREP8 (Ferguson, 1998 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809006278/bg2237sup1.cif

e-65-0m332-sup1.cif^{(47.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809006278/bg2237Isup2.hkl

e-65-0m332-Isup2.hkl^{(336KB, hkl)}

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

Enhanced figure: interactive version of Fig. 2

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C9—H9B⋯O1ⁱ	0.98	2.36	3.188 (6)	142
C13B—H13B⋯O2ⁱⁱ	0.95	2.58	3.510 (6)	167
C33B—H33B⋯Cg1	0.95	2.58	3.387 (5)	144
C35A—H35A⋯Cg2ⁱⁱⁱ	0.95	2.61	3.489 (6)	154

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) . Cg1 and Cg2 are the centroids of the C11A–C15A, C31B–C36B rings, respectively.

Acknowledgments

JFG thanks Dublin City University and PRTLI-3 (NICB) for grants in aid of chemical research.

supplementary crystallographic information

Comment

In the condensation reactions of benzoyl chlorides and amino derivatives containing an ortho-aromatic ring N atom (such as ortho-aminopyridine), two products can be isolated as either the 1:1 or 2:1 benzoyl:pyridine components and with yields and ratios depending on the reaction conditions. We have reported on the structure of the 1:1 derivative namely 2,3-difluoro-N-(2-pyridyl)benzamide (Gallagher et al., 2008) and two examples of a 2:1 relative namely the mono-fluoro derivatives, 2-Fluoro-N-(2-fluorobenzoyl)-N-(2-pyridyl)benzamide and 3-Fluoro-N-(3-fluorobenzoyl)-N-(2-pyridyl)benzamide (Gallagher et al., 2009a,b). Herein, we report an organometallic analogue of these systems where a sterically bulky ferrocenyl group has replaced the fluoro and a different pyridine ring system is used in the molecular scaffold, namely the electroactive molecular system 2-Ferrocenyl-N-(2-ferrocenylbenzoyl)-N-(4-methyl-2-pyridyl)benzamide (I).

The parent compound 2-(Dibenzoylamino)pyridine has been reported previously (Weng et al., 2006). A review of the literature suggests that structures of this type are rare despite the large number of substituted benzamides reported in the literature. Recently, the crystal structures of two compounds N-(3-Br-1,4-dioxo-1,4-dihydro-2-naphthyl)-2-Cl—N-(2-chlorobenzoyl)benzamide & N-(3-Br-1,4-dioxo-1,4-dihydro-2-naphthyl)-4-F—N-(4-fluorobenzoyl)benzamide have been reported (Akinboye et al., 2009a,b), but these differ substantially from (I) in the quinone scaffold or more specifically in the chloro-1,4-naphthoquinone skeleton. The molecular structure of a related compound which has been examined for protonation-controlled regulation of electronic communication, namely, N-Ferrocenecarbonyl-N-(2-pyridyl)ferrocenecarboxamide (Moriuchi & Hirao, 2007) is of interest for comparisons with (I) and also the parent compound (Weng et al., 2006).

(I) crystallizes in the triclinic system in space group P1 (No. 2) and forms an interesting twisted molecular structure in the solid state due to the steric demands of two ortho-substituted benzene rings (Figs. 1–2).

A short intramolecular hydrogen bond is present in (I) involving a substituted η⁵-(C₅H₄) ring and an ortho-H atom of the benzene ring on the opposite side of the molecule. The geometric data are H33B···Cg1 of 2.58 Å, C33B—H33B···Cg1 144° and C33B···Cg1 3.387 (5) Å (Cg1 is the centroid of the C11A-C15A ring). This is quite short and comparable to intramolecular _arC—H···η⁵-(C₅) ring interactions present in ferrocene-derived crystal structures deposited on the CSD (Allen, 2002). However, in the vast majority of crystal structures analysed (for such intramolecular interactions) the C—H is only 4/5 bonds from the C₅ ring and oriented on steric grounds to overlap with the cp ring whether this is energetically favourable or not. The intramolecular interaction in (I) is such that the C—H and substituted cyclopentadienyl ring can be considered to be 8 bonds from each other. However, given the steric demands within (I) a similar situation exists whereby the C—H is oriented towards the ring on steric grounds.

The crystal structure also contains three intermolecular interactions comprising a short C—H···π-(C₆) interaction {C₆ is the C31B-C36B ring system, with centroid Cg2} and two C—H···O=C weak interactions per molecule. The former is centrosymmetric and has the effect of (I) joining to form a dimer: the other interactions are less significant in terms of crystal structure packing.

Experimental

Compound (I) was synthesized via standard condensation procedures and similar to the related syntheses reported (Gallagher et al., 2009a,b). Separation of the 1:1 and 2:1 derivatives was undertaken by using flash chromatography using CHCl₃:ethyl acetate. Typical organic workup and washing gave the product (I) in modest yield of 30–40% as a 2:1 component of the mixture. Crystals suitable for X-ray diffraction were grown from CHCl₃ as colourless blocks over a period of 1–2 weeks. The compounds gave clean ¹H and ¹³C NMR spectra in CDCl₃ and infrared spectra (in CHCl₃ solution, and as KBr disks).