1,4-Diazo­niabicyclo­[2.2.2]octane bis­(2-chloro­benzoate)

Signe Skovsgaard; Andrew D Bond

doi:10.1107/S1600536808020096

. 2008 Jul 5;64(Pt 8):o1416. doi: 10.1107/S1600536808020096

1,4-Diazoniabicyclo[2.2.2]octane bis(2-chlorobenzoate)

Signe Skovsgaard ^a, Andrew D Bond ^a,^*

PMCID: PMC2962050 PMID: 21203135

Abstract

The title compound, C₆H₁₄N₂ ²⁺·2C₇H₄ClO₂ ⁻, contains trimeric units linked by N—H⋯O hydrogen bonds. The carboxylate groups of the 2-chlorobenzoate anions form dihedral angles of 66.1 (1) and 76.1 (1)° with the respective chlorobenzene rings to which they are bound. The hydrogen-bonded trimers are arranged in layers in the (200) planes and the chlorobenzoate anions form edge-to-face interactions between layers, with dihedral angles of 61.9 (1) and 49.8 (1)° and centroid–centroid distances of 4.85 (1) and 4.65 (1) Å, respectively, for two crystallographically distinct interactions.

Related literature

For other co-crystals of 1,4-diazoniabicyclo[2.2.2]octane and carboxylic acids, see: Meehan et al. (1997 ▶); Burchell et al. (2000 ▶); Burchell, Glidewell et al. (2001 ▶); Burchell, Ferguson et al. (2001 ▶). For the crystal structure of 2-chlorobenzoic acid, see: Ferguson & Sim (1961 ▶).

Experimental

Crystal data

C₆H₁₄N₂ ²⁺·2C₇H₄ClO₂ ⁻
M _r = 425.30
Orthorhombic,
a = 19.7694 (12) Å
b = 11.3986 (6) Å
c = 8.9751 (5) Å
V = 2022.5 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.35 mm⁻¹
T = 298 (2) K
0.30 × 0.20 × 0.10 mm

Data collection

Bruker–Nonius X8 APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2003 ▶) T _min = 0.844, T _max = 0.966
21779 measured reflections
3538 independent reflections
3251 reflections with I > 2σ(I)
R _int = 0.023

Refinement

R[F ² > 2σ(F ²)] = 0.033
wR(F ²) = 0.090
S = 1.06
3538 reflections
253 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.19 e Å⁻³
Absolute structure: Flack (1983 ▶), 1629 Friedel pairs
Flack parameter: −0.02 (5)

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT (Bruker, 2003 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808020096/bx2155sup1.cif

e-64-o1416-sup1.cif^{(21KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808020096/bx2155Isup2.hkl

e-64-o1416-Isup2.hkl^{(173.5KB, hkl)}

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
N1—H1A⋯O1	0.91	1.65	2.556 (2)	170
N2—H2A⋯O3	0.91	1.69	2.587 (2)	169

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Acknowledgments

We are grateful to the Danish Natural Science Research Council and the Carlsberg Foundation for provision of the X-ray equipment.

supplementary crystallographic information

Comment

The title compound, (C₆H₁₄N₂)(C₇H₄ClO₂)₂, was obtained by co-crystallization of diazabicylo[2.2.2]octane and 2-chlorobenzoic acid in methanol solution. The crystal structure of 2-chlorobenzoic acid (Ferguson & Sim, 1961) contains dimers formed by hydrogen bonds between the carboxyl groups. The purpose of the co-crystallization was to insert DABCO into the hydrogen-bonded dimer, to examine the influence on the intermolecular interactions between the 2-chlorobenzoic acid molecules.

The co-crystal contains the anticipated trimeric hydrogen-bond motif, with the trimers lying in layers parallel to the bc planes (Figs. 2 & 3). The Cl-substituents of the chlorobenzoate anions point into the centres of the layers, and the interlayer interactions comprise edge-to-face interactions involving H4A and H5A and their counterparts H11A and H12A, with dihedral angles 61.9 (1) and 49.8 (1)° and centroid-centroid distances 4.85 (1) and 4.65 (1) Å, for the two interactions respectively. The interactions are significantly different from the interlayer interactions in 2-chlorobenzoic acid itself, where adjacent rings form a dihedral angle of 49.3 (1)°, but the Cl-substituent points towards the adjacent ring centroid.

Experimental

Separate saturated solutions of 2-chlorobenzoic acid (0.391 g, 0.0025 mmol) and diazabicyclo[2.2.2]octane (0.135 g, 0.0012 mmol) in warm methanol were combined and refluxed with stirring for 1 h. The solution was cooled slowly, giving colourless crystals of the title compound after ca 1 h.