Cytosinium–hydrogen maleate–cytosine (1/1/1)

Nourredine Benali-Cherif; Wahiba Falek; Amani Direm

doi:10.1107/S1600536809046571

. 2009 Nov 11;65(Pt 12):o3058–o3059. doi: 10.1107/S1600536809046571

Cytosinium–hydrogen maleate–cytosine (1/1/1)

Nourredine Benali-Cherif ^a,^*, Wahiba Falek ^b, Amani Direm ^a

PMCID: PMC2972138 PMID: 21578789

Abstract

The title organic salt, C₄H₆N₃O⁺·C₄H₃O₄ ⁻·C₄H₅N₃O, was synthesized from cytosine base and maleic acid. An intramolecular O—H⋯O hydrogen bond occurs in the hydrogen maleate anion. The crystal packing is stabilized by intermolecular N—H⋯O, N—H⋯N and C—H⋯O hydrogen bonds, giving rise to a nearly planar two-dimensional network parallel to (101).

Related literature

For background to cytosine, see: Devlin (1986 ▶); Johnson & Coghill (1925 ▶); Mahan et al. (2004 ▶). For the structure of cytosine, see: Barker & Marsh (1964 ▶) and for that of cytosine monohydrate, see: Jeffrey & Kinoshita (1963 ▶); Swamy et al. (2001 ▶). For the stuctures of inorganic cytosinium salts, see: Mandel (1977 ▶); Cherouana et al. (2003 ▶); Jaskólski (1989 ▶); Bagieu-Beucher (1990 ▶) and for those of cytosinium salts of organic acids, see: Gdaniec et al. (1989 ▶); Smith et al. (2005 ▶); Balasubramanian et al. (1996 ▶). For the hydrogen maleate anion, see: Madsen & Larsen (1998 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). graphic file with name e-65-o3058-scheme1.jpg

Experimental

Crystal data

C₄H₆N₃O⁺·C₄H₃O₄ ⁻·C₄H₅N₃O
M _r = 338.29
Monoclinic,
a = 27.3226 (5) Å
b = 7.3618 (2) Å
c = 14.6742 (4) Å
β = 93.905 (1)°
V = 2944.77 (13) Å³
Z = 8
Mo Kα radiation
μ = 0.13 mm⁻¹
T = 298 K
0.3 × 0.15 × 0.1 mm

Data collection

Nonius KappaCCD diffractometer
Absorption correction: none
3490 measured reflections
3485 independent reflections
2603 reflections with I > 2σ(I)
R _int = 0.043

Refinement

R[F ² > 2σ(F ²)] = 0.048
wR(F ²) = 0.136
S = 1.07
3485 reflections
202 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.36 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Data collection: KappaCCD Server Software (Nonius, 1998 ▶); cell refinement: DENZO and SCALEPACK (Otwinowski & Minor, 1997 ▶); data reduction: DENZO and SCALEPACK; program(s) used to solve structure: SIR2004 (Burla et al., 2005 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and PLATON (Spek, 2009 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809046571/dn2509sup1.cif

e-65-o3058-sup1.cif^{(17.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809046571/dn2509Isup2.hkl

e-65-o3058-Isup2.hkl^{(167.5KB, 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
N1A—H1A⋯O4	0.86	1.89	2.7426 (19)	174
N1B—H1B⋯O2ⁱ	0.86	1.91	2.7701 (19)	174
N8A—H8A1⋯O7B	0.86	2.00	2.8582 (19)	178
N8A—H8A2⋯O7A ⁱⁱ	0.86	2.04	2.8329 (19)	153
N3B—H3B⋯N3A	0.86	1.98	2.8370 (19)	176
N8B—H8B1⋯O7A	0.86	1.99	2.8458 (19)	173
N8B—H8B2⋯O7B ⁱⁱⁱ	0.86	2.06	2.8491 (18)	153
O3—H3⋯O1	1.17 (2)	1.25 (2)	2.4167 (16)	173 (2)
C6B—H6B⋯O1ⁱ	0.93	2.50	3.186 (2)	131
C5B—H5B⋯O2^iv	0.93	2.42	3.330 (2)	165
C5A—H5A⋯O4ⁱⁱ	0.93	2.37	3.296 (2)	175

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

Acknowledgments

We wish to thank Dr M. Giorgi, Faculté des Sciences et Techniques de Saint Jérome, Marseille, France, for providing diffraction facilities and le Centre Universitaire de Khenchela for financial support.

supplementary crystallographic information

Comment

The pyrimidine base, Cytosine, leads to the nucleoside cytidine and its corresponding nucleotide: cytidine 5'-monophosphate. It may be found in very small quantities as a post-modified form, 5-methylcytosine, in certain nucleic acids (Devlin, 1986) such as in tuberculinic acid (Johnson & Coghill, 1925). More recently, 5-fluoro-cytosine (5-FC) has been used as a prodrug in suicide gene therapy of cancer with the crystal structure of bacterial cytosine deaminase (bCD) (Mahan et al., 2004).

The crystal structures of cytosine (Barker & Marsh, 1964) and cytosine monohydrate (Jeffrey & Kinoshita, 1963) were determined many years ago. (Swamy et al., 2001)]. Many inorganic cytosinium salts have been previously synthesized: chloride (Mandel, 1977), nitrate (Cherouana et al., 2003) and dihydrogenphosphate (Jaskólski, 1989; Bagieu-Beucher, 1990). Cytosinium salts of organic acids are also common, the structures of a number of these including trichloroacetate (Gdaniec et al., 1989), Cytosinium 3,5-dinitrosalicylate (Smith, et al., 2005) and hydrogen maleate (Balasubramanian et al., 1996) have been recently reported.

We report here the molecular structure of a novel compound (I) formed from the reaction of cytosine with maleic acid, namely cytosine cytosinium hydrogen maleate. It was prepared in order to extend our study on D—H···A hydrogen bonding in organic systems.

The asymmetric unit in (I) contains a hydrogen maleate anion, a cytosinium cation and a cytosine molecule which are held together by N—H···O and N—H···N hydrogen bonds (Fig. 1; Table 1). As observed in other hydrogen maleate anion, the H atom is roughly in between O1 and O3 (Madsen & Larsen, 1998).

In the crystal packing (Fig.2), cytosine bases and cytosinium cations are linked by N8A–H1N···O7A and N8B–H3N···O7B hydrogen-bonds forming a C(6)R²₂(8) graph-set motif and yielding infinite chains running parallel to the b axis. These chains are connected through N–H···O and C–H···O hydrogen bonds involving the O2 and O4 atoms of the maleate thus generating R²₃(10) and R²₂(7) graph-set motifs (Bernstein et al., 1995) and giving rise to a planar two-dimensionnal network parallel to the (1 0 1) plane (Table 1, Fig. 2).

Experimental

The title compound was prepared by the reaction between cytosine and maleic acid. A colorless prismatic single-cristals were grown after few days of evaporation at room temperature.