Triethyl­ammonium 2,4-dinitro­phenyl­barbiturate

Doraisamyraja Kalaivani; Rangasamy Malarvizhi

doi:10.1107/S1600536809036976

. 2009 Sep 26;65(Pt 10):o2548. doi: 10.1107/S1600536809036976

Triethylammonium 2,4-dinitrophenylbarbiturate

Doraisamyraja Kalaivani ^a,^*, Rangasamy Malarvizhi ^a

PMCID: PMC2970263 PMID: 21577990

Abstract

In the title molecular salt [systematic name: triethylammonium 5-(2,4-dinitrophenyl)-2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-olate], C₆H₁₆N⁺·C₁₀H₅N₄O₇ ⁻, the cation and anion are linked by an N—H⋯O hydrogen bond. In the crystal, inversion-related barbiturate rings are centrosymmetrically connected through pairs of N—H⋯O hydrogen bonds, forming R ₂ ²(8)R ₂ ²(8) ring motifs.

Related literature

For further information on the anticonvulsant properties of the title compound and general background, see: Kalaivani et al. (2008 ▶). For a related structure, see: Craven (1964 ▶). For data on hydrogen-bond motifs in organic crystals, see: Allen et al. (1998 ▶). graphic file with name e-65-o2548-scheme1.jpg

Experimental

Crystal data

C₆H₁₆N⁺·C₁₀H₅N₄O₇ ⁻
M _r = 395.38
Monoclinic,
a = 29.7900 (8) Å
b = 10.4533 (3) Å
c = 11.9606 (3) Å
β = 97.903 (1)°
V = 3689.20 (17) Å³
Z = 8
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 293 K
0.30 × 0.20 × 0.20 mm

Data collection

Bruker Kappa APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 1999 ▶) T _min = 0.942, T _max = 0.971
32882 measured reflections
3217 independent reflections
2493 reflections with I > 2σ(I)
R _int = 0.036

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.109
S = 1.04
3217 reflections
268 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.46 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT-Plus (Bruker, 2004 ▶); data reduction: SAINT-Plus and XPREP (Bruker, 2004 ▶); program(s) used to solve structure: SIR92 (Altornare et al., 1993 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809036976/hb5061sup1.cif

e-65-o2548-sup1.cif^{(21KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809036976/hb5061Isup2.hkl

e-65-o2548-Isup2.hkl^{(154.7KB, 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—H1⋯O1ⁱ	0.84 (2)	2.02 (2)	2.861 (2)	177 (2)
N2—H2⋯O3ⁱⁱ	0.82 (2)	2.10 (2)	2.918 (2)	172 (2)
N5—H5⋯O2	0.85 (2)	1.88 (2)	2.730 (2)	172 (2)

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

Acknowledgments

The authors are thankful to SAIF, IIT Madras, for the crystal data.

supplementary crystallographic information

Comment

We have recently prepared the title compound, (I), which has anticonvulsant activity (Kalaivani et al., 2008). We now report its crystal structure.

ORTEP view of the title compound is shown in Fig. 1. The presence of the leaving group (chlorine atom) para with respect to the nitrogroup of the starting molecule (1 – chloro – 2,4 – dinitrobenzene) facilitates the formation of the title compound in the presence of barbituric acid and triethylamine. Absence of chlorine atom, as indicated by the qualitative test on the synthesized barbirutrate has been supported by the crystallographic data. The title molecule is coloured red and it has been attributed to the delocalization of negative charge (Kalaivani et al., 2008) which has also been substantiated by the bond angles and bond lengths of single-crystal X-ray data of 2,4-dinitrophenyl and barbiturate rings. The bond angles and bond lengths of barbiturate residue of the title molecule are compatible with that of barbiturate ion (Craven, 1964), evidencing the delocalization of negative charge in the barbiturate ring.

Presence of double bond (delocalized) between C3 and C5 atoms fixes the configuration of the molecule as depicted in Fig. 1. The N5—H5···O2 hydrogen bond between the asymmetric units is the main driving force for the orientation of the triethylammonium cation (Fig. 2). Two inversion related barbiturate anions interact through a pair of N—H···O=C hydrogen bonds involving N1—H1 atoms and the carbonyl oxygen atom (O1) forming a R₂²(8) ring motif. The same ring motif is also due to a pair of N—H···O hydrogen bonds involving N2—H2 atoms and the carbonyl oxygen atom (O3). This motif is one of the 24 most frequently observed bimolecular cyclic hydrogen-bonded motifs in organic crystal structures (Allen et al., 1998). The hydrogen bonds observed in the title molecule are mainly responsible for its stability. The high solubility of the title drug molecule in water (4 g cc^-1 at 298 K) is due to the positively charged triethylammonium cation and negatively charged 2,4-dinitrophenylbarbiturate anion of the asymmetric unit.

Experimental

The title compound was prepared as described previously (Kalaivani et al., 2008) and recrystallized from absolute ethanol to yield maroon blocks of (I).