1-{2-[4-(4-Nitro­phen­yl)piperazin-1-yl]eth­yl}-4-aza-1-azoniabicyclo­[2.2.2]octane iodide

Anssi Peuronen; Manu Lahtinen

doi:10.1107/S1600536812024531

. 2012 Jun 2;68(Pt 7):o1986. doi: 10.1107/S1600536812024531

1-{2-[4-(4-Nitrophenyl)piperazin-1-yl]ethyl}-4-aza-1-azoniabicyclo[2.2.2]octane iodide

Anssi Peuronen ^a, Manu Lahtinen ^a,^*

PMCID: PMC3393262 PMID: 22807819

Abstract

The title compound, C₁₈H₂₈N₅O₂ ⁺·I⁻, was observed as a main product in an intended 1:1 reaction between 4-iodonitrobenzene and 1,4-diazabicyclo[2.2.2]octane (DABCO). In the reaction, DABCO undergoes a ring opening to yield a quaternary salt of DABCO and 1-ethyl-4-(4-nitrophenyl)piperazine with an iodide anion. The crystal structure determination was carried out as no crystal structure had been previously reported in the investigations describing the corresponding reaction with 4-chloronitrobenze. Indeed, the crystal structure of the title compound confirms the molecular composition proposed earlier for the analogous chloride salt. The cation conformation is similar to the previously reported dinitro analogue 1-{2-[4-(2,4-dinitrophenyl)piperazin-1-yl]ethyl}-4-aza-1-azoniabicyclo[2.2.2]octane chloride [Clegg et al. (2004 ▶). Acta Cryst. E60, o291–o293]. The crystal packing is dominated by cation⋯I⁻ interactions in addition to weak intermolecular C—H⋯O₂N and C—H⋯N interactions between the cations.

Related literature

For a possible route of synthesis for the chloride salt of the title compound, see: Ross & Finkelstein (1963 ▶). For a related structure, see: Clegg et al. (2004 ▶). For the synthesis of the intended 1:1 product of DABCO and 4-iodonitrobenzene, see Ibata et al. (1987 ▶).

Experimental

Crystal data

C₁₈H₂₈N₅O₂ ⁺·I⁻
M _r = 473.35
Monoclinic,
a = 9.758 (1) Å
b = 10.702 (1) Å
c = 20.187 (2) Å
β = 110.124 (3)°
V = 1979.4 (3) Å³
Z = 4
Mo Kα radiation
μ = 1.64 mm⁻¹
T = 123 K
0.40 × 0.24 × 0.16 mm

Data collection

Bruker–Nonius KappaCCD diffractometer with an APEXII detector
Absorption correction: multi-scan (SADABS; Sheldrick, 2008b ▶) T _min = 0.617, T _max = 0.746
12011 measured reflections
3855 independent reflections
3473 reflections with I > 2σ(I)
R _int = 0.032

Refinement

R[F ² > 2σ(F ²)] = 0.029
wR(F ²) = 0.060
S = 1.10
3855 reflections
235 parameters
H-atom parameters constrained
Δρ_max = 0.48 e Å⁻³
Δρ_min = −0.44 e Å⁻³

Data collection: COLLECT (Bruker, 2008 ▶); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997 ▶); data reduction: DENZO-SMN; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008a ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008a ▶); molecular graphics: Mercury (Macrae et al. 2008 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812024531/nr2029sup1.cif

e-68-o1986-sup1.cif^{(29.3KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812024531/nr2029Isup2.hkl

e-68-o1986-Isup2.hkl^{(185.2KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812024531/nr2029Isup3.cml

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C2—H2B⋯O1ⁱ	0.99	2.52	3.051 (3)	113
C5—H5A⋯O2ⁱⁱ	0.99	2.47	3.414 (3)	160
C6—H6B⋯O1ⁱⁱ	0.99	2.59	3.141 (3)	116
C14—H14⋯I1ⁱ	0.95	3.02	3.914 (3)	158
C17—H17⋯O2ⁱⁱⁱ	0.95	2.48	3.412 (3)	168
C18—H18⋯N1^iv	0.95	2.45	3.384 (3)	166

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

Acknowledgments

The authors would like to thank the Inorganic Materials Chemistry Graduate Program for financial support.

supplementary crystallographic information

Comment

The reaction between DABCO and 4-chloronitrobenzene has first been reported by Ross & Finkelstein (1963). The product obtained was identified as the chloride salt analogue of the title compound, 1-(4-nitrophenyl)-4-aza-1-azoniabicyclo[2.2.2]octane chloride, instead of the expected 1:1 product. We were interested in the synthesis of the elusive 1:1 product for its potential applications in supramolecular chemistry based on halogen bonding interactions. We tried to use 4-iodonitrobenzene in order to obtain the 1:1 product. Regardless of the milder conditions (THF at reflux for 48 h) and a different halobenzene, the corresponding reaction proceeds according to the aforementioned route yielding an analogous iodide salt, 1-(4-nitrophenyl)-4-aza-1-azoniabicyclo[2.2.2]octane iodide, to the compound described above. Nonetheless, despite the failure in the intended synthesis, the crystal structure of the title compound provides a crystallographic evidence for the previously described reaction between DABCO and a 4-halonitrobenzene. Furthermore, our investigation suggests that changing the halogen atom in the 4-halonitrobenzene from chloride to iodine has evidently no effect in the outcome of the reaction (except that of different anion). A possible route for the anticipated 1:1 product is described by Ibata et al. (1987).

The cation of the title salt lies in a conformation similar to the previously reported dinitrobenzene analogue (Clegg et al., 2004). The labeling scheme is shown in Fig. 1. The intermolecular interactions in the crystal structure comprise mostly of weak C—H···O₂N interactions between DABCO –CH₂ groups and the –NO₂ groups [C···O distances range from 3.051 (3) to 3.414 (3)]. These short intermolecular contacts are most likely due to the attractive interactions between highly electronegative O atoms in the nitro groups and electropositive H atoms near the quaternary ammonium center. These are accompanied by presumably weaker aryl –CH···O₂N [d(C17···O2) = 3.412 (3)], aryl –CH···I^- [d(C14···I1) = 3.914 (3)] and aryl –CH···N (DABCO) [d(C18···N1) = 3.412 (3)] interactions (Fig. 2). The ordering of the ion pairs are shown in Fig. 3.

Experimental

The title compound was obtained as a major product in a reaction between DABCO (2.0 mmol) and 4-iodonitrobenzene (2.0 mmol) carried out in THF (48 h at reflux). After the removal of solvent the yellow oily residue was precipitated with dichloromethane, filtered and recrystallized from water/acetone mixture to yield a batch of yellow crystals of the title compound.